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During June 2017–November 2019, a total 36 patients with carbapenem-resistant Pseudomonas aeruginosa harboring Verona-integron–encoded metallo-β-lactamase were identified in a city in western Texas, USA. A faucet contaminated with the organism, identified through environmental sampling, in a specialty care room was the likely source for infection in a subset of patients.

Over the last 20 years there have been 32 reports of carbapenem-resistant organisms in the hospital water environment, with half of these occurring since 2010. The majority of these reports have described associated clinical outbreaks in the intensive care setting, affecting the critically ill and the immunocompromised. Drains, sinks, and faucets were most frequently colonized, and Pseudomonas aeruginosa the predominant organism. Imipenemase (IMP), Klebsiella pneumoniae carbapenemase (KPC), and Verona integron-encoded metallo-β-lactamase (VIM) were the most common carbapenemases found. Molecular typing was performed in almost all studies, with pulse field gel electrophoresis being most commonly used. Seventy-two percent of studies reported controlling outbreaks, of which just more than one-third eliminated the organism from the water environment. A combination of interventions seems to be most successful, including reinforcement of general infection control measures, alongside chemical disinfection. The most appropriate disinfection method remains unclear, however, and it is likely that replacement of colonized water reservoirs may be required for long-term clearance.

In a national online survey, 1,020 participants reported their perceptions of water use for household activities. When asked for the most effective strategy they could implement to conserve water in their lives, or what other Americans could do, most participants mentioned curtailment (e.g., taking shorter showers, turning off the water while brushing teeth) rather than efficiency improvements (e.g., replacing toilets, retrofitting washers). This contrasts with expert recommendations. Additionally, some participants are more likely to list curtailment actions for themselves, but list efficiency actions for other Americans. For a sample of 17 activities, participants underestimated water use by a factor of 2 on average, with large underestimates for high water-use activities. An additional ranking task showed poor discrimination of low vs. high embodied water content in food products. High numeracy scores, older age, and male sex were associated with more accurate perceptions of water use. Overall, perception of water use is more accurate than the perception of energy consumption and savings previously reported. Well-designed efforts to improve public understanding of household water use could pay large dividends for behavioral adaptation to temporary or long-term decreases in availability of fresh water.

Effect of the preload of the bolt and elastic deformation of the spigot on the dynamic behavior of the bolted flange is usually neglected in the traditional models. Furthermore, there are limited studies on the vibration characteristics of the rolling bearing and bolted rotor system with spigot. In this paper, an analytical model of the bolted flange with spigot is proposed. The spigot is simulated by a rotational spring and the dynamic behaviors at the spigot interface are simulated by the Jenkins element. Moreover, the preload and deformation of the bolt are considered. The results under axial load and harmonic load of the proposed model show good agreement with the results of the three-dimensional (3D) finite element (FE) simulation. To improve the calculation efficiency of calculating the dynamic behavior at the interface, a Gaussian process (GP) model is constructed to predict the tensile load under various displacements and preloads. Then, a nonlinear vibration analysis of a rolling bearing-bolted rotor system with a spigot is conducted. Detailed parametric analyses under small and large unbalance loads, including interference fit, preload of the bolt and number of the bolt, are conducted to investigate the vibration characteristics of the rotor system. Results show that the bolted joint with spigot mainly produces stiffness loss and damping at the interface. Under large unbalance load, the dynamic characteristics are affected significantly. Moreover, the first two critical speeds can be increased by increasing the interference fit, preload of the bolt and number of the bolt.

The spigot is a common connecting method for composite containers with thin walls. The fixture is closer to the thin-walled cylindrical shell with one end clamped and one end supported (C-SS) than the boundary conditions of typical pressure vessels, which are supported (SS-SS) or clamped (C-C) at both ends. Under the boundary condition, there are very few calculations and experimental research. A buckling model of the thin-walled composite vessel was built, and the critical load was determined using the energy technique and the classical thin-walled theory. Using nonlinear numerical analysis and FEM, the buckling mode was simulated. Numerical examples were used to examine the impacts of the spigot’s length, boundary conditions, layup thickness, and sequencing on the critical load. The findings indicate that a shorter spigot, a thicker layup, and a small-angle layer closer to the center all increase the critical load. The boundary conditions of SS-SS, C-S, and C-C experienced increasing critical loads in that order; the latter was around 1.5~2 times more than the former. Ultimately, external pressure tests were used to evaluate the buckling critical loads of two distinct laminated thin-walled composite vessels, confirming the correctness of both the FEM results and the theoretical model. The variance for the former was 15%, while the latter was 8%. The findings can serve as guidelines for designing interference and winding pre-stress spigots and the structural stability study of thin-walled composite vessels.

Concern about lead in drinking water has heightened since the Flint water crisis. Moreover, recent medical evidence increasingly shows damage to children’s health at levels of lead exposure once considered low. In order to better protect children from these hazards, the American Academy of Pediatrics (AAP) recommends that drinking water in public schools does not exceed 1 μg/L lead. Meeting this goal with current plumbing and fixtures will be challenging, because current “lead-free” standards did not anticipate targets this low. Three styles of recently manufactured “lead-free” faucets were tested and average lead leaching ranged from 1.5 μg/L to 3.0 μg/L after 19 d. Given that the NSF/ANSI 61 test water is less aggressive than some potable waters, even newly manufactured “lead-free” faucets may not meet the standards recommended by AAP.

Bridge-like lipid-transport proteins (BLTPs) are an evolutionarily conserved family of proteins that localize to membrane-contact sites and are thought to mediate the bulk transfer of lipids from a donor membrane, typically the endoplasmic reticulum, to an acceptor membrane, such as that of the cell or an organelle 1 . Although BLTPs are fundamentally important for a wide array of cellular functions, their architecture, composition and lipid-transfer mechanisms remain poorly characterized. Here we present the subunit composition and the cryogenic electron microscopy structure of the native LPD-3 BLTP complex isolated from transgenic Caenorhabditis elegans . LPD-3 folds into an elongated, rod-shaped tunnel of which the interior is filled with ordered lipid molecules that are coordinated by a track of ionizable residues that line one side of the tunnel. LPD-3 forms a complex with two previously uncharacterized proteins, one of which we have named Spigot and the other of which remains unnamed. Spigot interacts with the N-terminal end of LPD-3 where lipids are expected to enter the tunnel, and experiments in multiple model systems indicate that Spigot has a conserved role in BLTP function. Our LPD-3 complex structural data reveal protein–lipid interactions that suggest a model for how the native LPD-3 complex mediates bulk lipid transport and provides a foundation for mechanistic studies of BLTPs. The LPD-3 complex structure reveals protein–lipid interactions that suggest a model for how the native LPD-3 complex mediates bulk lipid transport and provides a foundation for mechanistic studies of bridge-like lipid-transport proteins.

Bolted spigot joints are widely used connection types in rotating machines, such as the rotor system of aero-engines and combustion gas turbines. Due to the nonlinearity of stiffness and damping caused by the bolted joint and mating interface friction, the dynamic performance of such a connection is too complicated to model. Therefore, the modelling and analysis of bolted spigot joints considering mating interface friction have become of interest in relevant investigations at present, which are of significance for predictions focusing on vibration performance. In this paper, the stick–slip behaviour and hysteresis characteristics of bolted spigot joints caused by mating interface friction are clarified by performing a study with a finite contact element model. Then, a new Iwan-based numerical model of bolted joints is proposed and an effective discretized parameter identification method is developed using the force–displacement results corresponding to the loading process obtained from finite element (FE) simulation results. A comparison study of the established numerical model and the FE simulation results demonstrates the potential of this numerical model to capture the static hysteresis behaviour and vibration performance. Then, the influences of the preload and loading amplitude of bolted joints on the static hysteresis behaviour and vibration performance of the system are examined using the numerical model. Finally, utilizing the results of bolted joint vibration response experiments performed with the established vibration test platform, the results of the numerical simulation are verified. The present study provides a theoretical basis for the design of the joint structure and assembly technology, which further enhances its prediction accuracy of dynamic performance.

Microbial drinking water quality can be altered in large buildings, especially after stagnation. In this study, bacterial profiles were generated according to the stagnation time and the volume of water collected at the tap. Successive volumes of cold and hot water were sampled after controlled stagnation periods. Bacterial profiles revealed an important decline (> 2 log) in culturable cells in the first 500 mL sampled from the hot and cold water systems, with a steep decline in the first 15 mL. The strong exponential correlation (R2 ≥ 0.97) between the culturable cell counts in water and the pipe surface-to-volume ratio suggests the biofilm as the main contributor to the rapid increase in suspended culturable cells measured after a short stagnation of one-hour. Results evidence the contribution of the high surface-to-volume ratio at the point of use and the impact of short stagnation times on the increased bacterial load observed. Simple faucets with minimal internal surface area should be preferred to minimize surface area. Sampling protocol, including sampling volume and prior stagnation, was also shown to impact the resulting culturable cell concentration by more than 1000-fold. Sampling a smaller volume on first draw after stagnation will help maximize recovery of bacteria.