RISK OF COVID-19 MOVEMENT AND EXPOSURE ON PASSENGER RAILCARS: ASSESSMENT OF AEROSOL TRANSPORT AND RAILCAR VENTILATION SYSTEMS

We conducted a series of static and dynamic experiments in a fleet of passenger railcars and locomotives for a large-scale, mass-transit company to measure the: (1) aerosol concentrations corresponding to respirable-sized/viral aerosols; (2) aerosol removal rates; and (3) air changes per hour (ACH) provided by the existing air handling systems. We evaluated the ventilation and air filtration (HVAC) systems effectiveness in a range of representative conditions to assess exposure risk. The risk of exposure to SARS-CoV-2 was assessed: (1) under standard conditions; (2) using minimum reported efficiency value (MERV) filters with increased filtration ratings; and (3) in the presence of a high-efficiency particulate-absorbing (HEPA)-scavenging system. The engineering controls evaluated included: (1) recirculated to fresh air ventilation ratio; (2) MERV filters filtration efficiency; and (3) use of an air purifier. Aerosols were generated in the 0.3–5.0 µm size range using a Collison Nebulizer. Real-time aerosol concentrations were measured at multiple locations using photodetector particle counters. The ACHs and removal rates were calculated using log-linear regression. An analysis of variance was used to compare the particle concentrations under the different experimental conditions while a multiple linear regression was used to identify which engineering control(s) impacted the particle concentrations. The risk of exposure was estimated using an approach developed by Miller et al. The recirculated to fresh air ratio had a minimal effect on particle air concentrations and on particle removal rates. The higher efficiency MERV13 filters significantly reduced particle concentrations (p<0.05) and significantly increased particle removal rates (p<0.01) compared to MERV8 filters. Compared to standard conditions, MERV13 filters reduced the exposure risk by 42%. Use of a HEPA-scavenger with a MERV13 filter causes a further reduction in risk (by 50%). The risk of exposure in the engine locomotives was much lower than in the passenger railcars due to much higher ACH values. These results show that a simple upgrade in the efficiency of the HVAC filters results in reductions of particle concentration and risk of exposure in public-transit vehicles. Widespread upgrading of HVAC filter efficiency in public-transit vehicles could reduce community-spread infectious respiratory diseases, protect transit workers, and slow disease spread

Mentholation affects the cigarette microbiota by selecting for bacteria resistant to harsh environmental conditions and selecting against potential bacterial pathogens

There is a paucity of data regarding the microbial constituents of tobacco products and their impacts on public health. Moreover, there has been no comparative characterization performed on the bacterial microbiota associated with the addition of menthol, an additive that has been used by tobacco manufacturers for nearly a century. To address this knowledge gap, we conducted bacterial community profiling on tobacco from user- and custom-mentholated/non-mentholated cigarette pairs, as well as a commercially-mentholated product. Total genomic DNA was extracted using a multi-step enzymatic and mechanical lysis protocol followed by PCR amplification of the V3-V4 hypervariable regions of the 16S rRNA gene from five cigarette products (18 cigarettes per product for a total of 90 samples): Camel Crush, user-mentholated Camel Crush, Camel Kings, custom-mentholated Camel Kings, and Newport Menthols. Sequencing was performed on the Illumina MiSeq platform and sequences were processed using the Quantitative Insights Into Microbial Ecology (QIIME) software package. In all products, Pseudomonas was the most abundant genera and included Pseudomonas oryzihabitans and Pseudomonas putida, regardless of mentholation status. However, further comparative analysis of the five products revealed significant differences in the bacterial compositions across products. Bacterial community richness was higher among non-mentholated products compared to those that were mentholated, particularly those that were custom-mentholated. In addition, mentholation appeared to be correlated with a reduction in potential human bacterial pathogens and an increase in bacterial species resistant to harsh environmental conditions. Taken together, these data provide preliminary evidence that the mentholation of commercially available cigarettes can impact the bacterial community of these products.https://doi.org/10.1186/s40168-017-0235-

Occupational exposure monitoring data collection, storage, and use among state-based and private workers' compensation insurers

<p>Despite substantial financial and personnel resources being devoted to occupational exposure monitoring (OEM) by employers, workers' compensation insurers, and other organizations, the United States (U.S.) lacks comprehensive occupational exposure databases to use for research and surveillance activities. OEM data are necessary for determining the levels of workers' exposures; compliance with regulations; developing control measures; establishing worker exposure profiles; and improving preventive and responsive exposure surveillance and policy efforts. Workers' compensation insurers as a group may have particular potential for understanding exposures in various industries, especially among small employers. This is the first study to determine how selected state-based and private workers' compensation insurers collect, store, and use OEM data related specifically to air and noise sampling.</p> <p> Of 50 insurers contacted to participate in this study, 28 completed an online survey. All of the responding private and the majority of state-based insurers offered industrial hygiene (IH) services to policyholders and employed 1 to 3 certified industrial hygienists on average. Many, but not all, insurers used standardized forms for data collection, but the data were not commonly stored in centralized databases. Data were most often used to provide recommendations for improvement to policyholders. Although not representative of all insurers, the survey was completed by insurers that cover a substantial number of employers and workers. The 20 participating state-based insurers on average provided 48% of the workers' compensation insurance benefits in their respective states or provinces. These results provide insight into potential next steps for improving the access to and usability of existing data as well as ways researchers can help organizations improve data collection strategies. This effort represents an opportunity for collaboration among insurers, researchers, and others that can help insurers and employers while advancing the exposure assessment field in the U.S.</p

Little cigars and cigarillos harbor diverse bacterial communities that differ between the tobacco and the wrapper.

Despite their potential importance with regard to infectious and chronic diseases among tobacco users, microbial constituents of tobacco products lack characterization. Specifically, to our knowledge, there are no data describing the bacterial diversity of little cigars or cigarillos. To address this knowledge gap, we tested four brands of little cigars and cigarillos. Tobacco and wrapper subsamples (n = 132) were separately subjected to DNA extraction, followed by PCR amplification of the V3V4 hypervariable region of the 16S rRNA gene, and sequencing using Illumina HiSeq. Sequences were analyzed using QIIME and Phyloseq implemented in R. We identified 2,681 operational taxonomic units across all products. Significant differences in alpha and beta diversity were observed between Swisher Sweets and Cheyenne products. Alpha and beta diversity was also significantly different between tobacco and wrapper subsamples within the same product. Beta diversity analyses of only tobacco samples identified no significant differences in the bacterial microbiota of different lots of the same products; however, the microbiota in the wrapper differed significantly across lots for all brands. Overall, Firmicutes were found to dominate in the wrapper, whereas Proteobacteria were most abundant in the tobacco. At the genus level, Bacillus and Lactobacillus dominated in the wrappers, and Staphylococcus and Pseudomonas dominated in the tobacco. Our findings suggest that the bacterial microbiota of little cigars and cigarillos is diverse and differs significantly between the tobacco and the wrapper, and across brands. Future work is necessary to evaluate the potential public health implications of these findings

IPv6 Security

IPv4 network addresses are running out and the deployment of IPv6 networking in many places is now well underway. Following the work of the HEPiX IPv6 Working Group, a growing number of sites in the Worldwide Large Hadron Collider Computing Grid (WLCG) are deploying dual-stack IPv6/IPv4 services. The aim of this is to support the use of IPv6-only clients, i.e. worker nodes, virtual machines or containers. The IPv6 networking protocols while they do contain features aimed at improving security also bring new challenges for operational IT security. The lack of maturity of IPv6 implementations together with the increased complexity of some of the protocol standards raise many new issues for operational security teams. The HEPiX IPv6 Working Group is producing guidance on best practices in this area. This paper considers some of the security concerns for WLCG in an IPv6 world and presents the HEPiX IPv6 working group guidance for the system administrators who manage IT services on the WLCG distributed infrastructure, for their related site security and networking teams and for developers and software engineers working on WLCG applications

Deployment of IPv6-only CPU resources at WLCG sites

The fraction of Internet traffic carried over IPv6 continues to grow rapidly. IPv6 support from network hardware vendors and carriers is pervasive and becoming mature. A network infrastructure upgrade often offers sites an excellent window of opportunity to configure and enable IPv6. There is a significant overhead when setting up and maintaining dual-stack machines, so where possible sites would like to upgrade their services directly to IPv6 only. In doing so, they are also expediting the transition process towards its desired completion. While the LHC experiments accept there is a need to move to IPv6, it is currently not directly affecting their work. Sites are unwilling to upgrade if they will be unable to run LHC experiment workflows. This has resulted in a very slow uptake of IPv6 from WLCG sites. For several years the HEPiX IPv6 Working Group has been testing a range of WLCG services to ensure they are IPv6 compliant. Several sites are now running many of their services as dual-stack. The working group, driven by the requirements of the LHC VOs to be able to use IPv6-only opportunistic resources, continues to encourage wider deployment of dual-stack services to make the use of such IPv6-only clients viable. This paper presents the working group’s plan and progress so far to allow sites to deploy IPv6-only CPU resources. This includes making experiment central services dual-stack as well as a number of storage services. The monitoring, accounting and information services that are used by jobs also need to be upgraded. Finally the VO testing that has taken place on hosts connected via IPv6-only is reported

IPv6-only networking on WLCG

The use of IPv6 on the general Internet continues to grow. The transition of the Worldwide Large Hadron Collider Computing Grid (WLCG) central and storage services to dual-stack IPv6/IPv4 is progressing well, thus enabling the use of IPv6-only CPU resources as agreed by the WLCG Management Board and presented by us at earlier CHEP conferences. During the last year, the HEPiX IPv6 Working Group has continued to chase and support the transition to dual-stack services. We present the status of the transition and some tests that have been made of IPv6-only CPU showing the successful use of IPv6 protocols in accessing WLCG services. The dual-stack deployment does however result in a networking environment which is more complex than when using just IPv6. The group is investigating the removal of the IPv4 protocol in places. We present the areas where this could be useful together with our future plans

IPv6 in production: its deployment and usage in WLCG

The fraction of general internet traffic carried over IPv6 continues to grow rapidly. The transition of WLCG central and storage services to dual-stack IPv4/IPv6 is progressing well, thus enabling the use of IPv6-only CPU resources as agreed by the WLCG Management Board and presented by us at CHEP2016. By April 2018, all WLCG Tier-1 data centres should have provided access to their services over IPv6. The LHC experiments have requested all WLCG Tier-2 centres to provide dual-stack access to their storage by the end of LHC Run 2. This paper reviews the status of IPv6 deployment in WLCG