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Cu is an antimicrobial that is commonly applied to premise (i.e., building) plumbing systems for Legionella control, but the precise mechanisms of inactivation are not well defined. Here, we applied a suite of viability assays and mass spectrometry-based proteomics to assess the mechanistic effects of Cu on L. pneumophila. Although a five- to six-log reduction in culturability was observed with 5 mg/L Cu2+ exposure, cell membrane integrity only indicated a <50% reduction. Whole-cell proteomic analysis revealed that AhpD, a protein related to oxidative stress, was elevated in Cu-exposed Legionella relative to culturable cells. Other proteins related to cell membrane synthesis and motility were also higher for the Cu-exposed cells relative to controls without Cu. While the proteins related to primary metabolism decreased for the Cu-exposed cells, no significant differences in the abundance of proteins related to virulence or infectivity were found, which was consistent with the ability of VBNC cells to cause infections. Whereas the cell-membrane integrity assay provided an upper-bound measurement of viability, an amoebae co-culture assay provided a lower-bound limit. The findings have important implications for assessing Legionella risk following its exposure to copper in engineered water systems.
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Background: The commensal skin bacterium Cutibacterium acnes plays a role in the pathogenesis of acne vulgaris and also causes opportunistic infections of implanted medical devices due to its ability to form biofilms on biomaterial surfaces. Poly-ß-(1â6)-N-acetyl-D-glucosamine (PNAG) is an extracellular polysaccharide that mediates biofilm formation and biocide resistance in a wide range of bacterial pathogens. The objective of this study was to determine whether C. acnes produces PNAG, and whether PNAG contributes to C. acnes biofilm formation and biocide resistance in vitro. Methods: PNAG was detected on the surface of C. acnes cells by fluorescence confocal microscopy using the antigen-specific human IgG1 monoclonal antibody F598. PNAG was detected in C. acnes biofilms by measuring the ability of the PNAG-specific glycosidase dispersin B to inhibit biofilm formation and sensitize biofilms to biocide killing. Results: Monoclonal antibody F598 bound to the surface of C. acnes cells. Dispersin B inhibited attachment of C. acnes cells to polystyrene rods, inhibited biofilm formation by C. acnes in glass and polypropylene tubes, and sensitized C. acnes biofilms to killing by benzoyl peroxide and tetracycline. Conclusion: C. acnes produces PNAG, and PNAG contributes to C. acnes biofilm formation and biocide resistance in vitro. PNAG may play a role in C. acnes skin colonization, biocide resistance, and virulence in vivo.
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How likely are engineering PhD graduates to get a tenure-track faculty position in the United States? To answer this question, we analyzed aggregated yearly data on PhD graduates and tenure-track/tenured faculty members across all engineering disciplines from 2006 to 2021, obtained from the American Society of Engineering Education. The average likelihood for securing a tenure-track faculty position for engineering overall during this 16-year period was 12.4% (range = 10.9-18.5%), implying that roughly 1 in 8 PhD graduates attain such positions. After a significant decline from 18.5 to 10.9% between 2006 and 2014 (R2 = 0.62; P < 0.05), a trend consistent with a period of rising competition, the outlook has since stabilized between 11.3 and 12% (R2 = 0.04; P > 0.05). Given that most engineering PhD graduates will never secure a tenure-track faculty position, emphasizing alternative career tracks during doctoral training could align expectations better with reality.
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OBJECTIVES: In the US, violations of drinking water regulations are highest in lower-income rural areas overall, and particularly in Central Appalachia. However, data on drinking water use, quality, and associated health outcomes in rural Appalachia are limited. We sought to assess public and private drinking water sources and associated risk factors for waterborne pathogen exposures for individuals living in rural regions of Appalachian Virginia. METHODS: We administered surveys and collected tap water, bottled water, and saliva samples in lower-income households in two adjacent rural counties in southwest Virginia (bordering Kentucky and Tennessee). Water samples were tested for pH, temperature, conductivity, total coliforms, E. coli, free chlorine, nitrate, fluoride, heavy metals, and specific pathogen targets. Saliva samples were analyzed for antibody responses to potentially waterborne infections. We also shared water analysis results with households. RESULTS: We enrolled 33 households (83 individuals), 82% (n = 27) with utility-supplied water and 18% with private wells (n = 3) or springs (n = 3). 58% (n = 19) reported household incomes of <$20,000/year. Total coliforms were detected in water samples from 33% (n = 11) of homes, E. coli in 12%, all with wells or springs (n = 4), and Aeromonas, Campylobacter, and Enterobacter in 9%, all spring water (n = 3). Diarrhea was reported for 10% of individuals (n = 8), but was not associated with E. coli detection. 34% (n = 15) of saliva samples had detectable antibody responses for Cryptosporidium spp., C. jejuni, and Hepatitis E. After controlling for covariates and clustering, individuals in households with septic systems and straight pipes had significantly higher likelihoods of antibody detection (risk ratios = 3.28, 95%CI = 1.01-10.65). CONCLUSIONS: To our knowledge, this is the first study to collect and analyze drinking water samples, saliva samples, and reported health outcome data from low-income households in Central Appalachia. Our findings indicate that utility-supplied water in this region was generally safe, and individuals in low-income households without utility-supplied water or sewerage have higher exposures to waterborne pathogens.
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Agua Potable , Humanos , Agua Potable/microbiología , Virginia/epidemiología , Masculino , Adulto , Femenino , Persona de Mediana Edad , Saliva/microbiología , Microbiología del Agua , Calidad del Agua , Abastecimiento de Agua , Adulto Joven , Adolescente , Población Rural/estadística & datos numéricos , Anciano , Región de los Apalaches/epidemiología , Niño , PobrezaRESUMEN
Gaps in the United States Environmental Protection Agency (US EPA) Lead and Copper Rule (LCR) leave some consumers and their pets vulnerable to high cuprosolvency in drinking water. This study seeks to help proactive utilities who wish to mitigate cuprosolvency problems through the addition of orthophosphate corrosion inhibitors. The minimum doses of orthophosphate necessary to achieve acceptable cuprosolvency in relatively new copper pipe were estimated as a function of alkalinity via linear regressions for the 90th, 95th, and 100th percentile copper tube segments (R2 > 0.98, n = 4). Orthophosphate was very effective at reducing cuprosolvency in the short term but, in some cases, resulted in higher long-term copper concentrations than the corresponding condition without orthophosphate. Alternatives to predicting "long-term" results for copper tubes using simpler bench tests starting with fresh Cu(OH)2 solids showed promise but would require further vetting to overcome limitations such as maintaining water chemistry and orthophosphate residuals and to ensure comparability to results using copper tube.
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Agua Potable , Contaminantes Químicos del Agua , Estados Unidos , Cobre/análisis , Fosfatos , Abastecimiento de Agua , CorrosiónRESUMEN
PURPOSE: Cannabis utilization has increased over time for recreational and medical purposes due to its legalization or decriminalization. The effects of cannabis use on opioid utilization are not well understood. The primary objective was to evaluate the total opioid utilization, measured in morphine milligram equivalents (MME), in hospitalized trauma patients that tested positive for tetrahydrocannabinol (THC) on a urine drug screen (UDS). METHODS: This was a retrospective, cohort study in a level 1 trauma center between 10/17/17 and 12/31/19. Adult trauma patients (aged 15 years and older) who had a UDS completed within 48 h of hospital arrival were eligible for inclusion. Patients were excluded for a hospitalization >14 days, death within 24 h, severe alcohol withdrawal, prescribed cannabinoids, high daily opioid use prior-to-arrival, or transitioned to hospice or palliative care. Group assignments were determined based on the presence or absence of THC on the UDS. RESULTS: The analysis included 750 patients with 160 (21 %) THC positive patients. The population were primarily male (64.6 %), median age of 56 years [IQR 35-72], with blunt (93 %) injuries from motor vehicle crash or falls (79 %). The THC group was more likely to have other substances present, including amphetamines, benzodiazepines, opiates, and cocaine. The THC group had a higher median injury severity score (10 [IQR 5-17] vs. 9 [5-14], p = 0.0056), and maximum abbreviated injury score (3 [IQR 2-3] vs. 2 [IQR 2-3], p = 0.0009). The THC group had a total higher median opioid utilization during the hospitalization (155 [IQR 68-367] vs. 62 [IQR 13-175] MME; p < 0.0001), which included higher opioid use in the emergency department, floor, and intensive care unit. There were no significant differences in secondary outcomes except the THC group was more likely to receive an opioid prescription at discharge and more likely to require mechanical ventilation. Based on multivariable regression analyses, other variables were associated with increased opioid utilization. CONCLUSION: Pre-existing THC exposure may be associated with an increased hospital opioid utilization in a trauma population. However, other variables may also play a role in opioid utilization.
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Alcoholismo , Cannabis , Endrín/análogos & derivados , Síndrome de Abstinencia a Sustancias , Adulto , Humanos , Masculino , Persona de Mediana Edad , Anciano , Estudios Retrospectivos , Analgésicos Opioides/uso terapéutico , Estudios de Cohortes , Síndrome de Abstinencia a Sustancias/tratamiento farmacológico , HospitalesRESUMEN
A 64-year-old man had progressive unsteadiness over several years, with tingling in his feet. He was a longstanding bodybuilding enthusiast. Clinical assessment and neurophysiology confirmed a cerebellar ataxia and axonal peripheral neuropathy. His serum mercury concentration was significantly raised. We diagnosed chronic mercury toxicity secondary to excessive tuna consumption. We advised him to stop eating tuna and prescribed dimercaptosuccinic acid, after which his serum mercury concentrations subsequently fell. This case report highlights the importance of considering dietary and nutritional causes of neurological disease. We also discuss the mechanisms, diagnosis and treatment of mercury toxicity.
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Intoxicación por Mercurio , Humanos , Masculino , Persona de Mediana Edad , Intoxicación por Mercurio/diagnóstico , Intoxicación por Mercurio/complicaciones , Mercurio/sangre , Mercurio/toxicidad , Levantamiento de PesoRESUMEN
In-building disinfectants are commonly applied to control the growth of pathogens in plumbing, particularly in facilities such as hospitals that house vulnerable populations. However, their application has not been well optimized, especially with respect to interactive effects with pipe materials and potential unintended effects, such as enrichment of antibiotic resistance genes (ARGs) across the microbial community. Here, we used triplicate convectively mixed pipe reactors consisting of three pipe materials (PVC, copper, and iron) for replicated simulation of the distal reaches of premise plumbing and evaluated the effects of incrementally increased doses of chlorine, chloramine, chlorine dioxide, and copper-silver disinfectants. We used shotgun metagenomic sequencing to characterize the resulting succession of the corresponding microbiomes over the course of 37 weeks. We found that both disinfectants and pipe material affected ARG and microbial community taxonomic composition both independently and interactively. Water quality and total bacterial numbers were not found to be predictive of pathogenic species markers. One result of particular concern was the tendency of disinfectants, especially monochloramine, to enrich ARGs. Metagenome assembly indicated that many ARGs were enriched specifically among the pathogenic species. Functional gene analysis was indicative of a response of the microbes to oxidative stress, which is known to co/cross-select for antibiotic resistance. These findings emphasize the need for a holistic evaluation of pathogen control strategies for plumbing.
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Desinfectantes , Agua Potable , Ingeniería Sanitaria , Desinfectantes/farmacología , Abastecimiento de Agua , Antibacterianos/farmacología , Cobre , Proliferación CelularRESUMEN
A framework is needed to account for interactive effects of plumbing materials and disinfectants on opportunistic pathogens (OPs) in building water systems. Here we evaluated free chlorine, monochloramine, chlorine dioxide, and copper-silver ionization (CSI) for controlling Pseudomonas aeruginosa and Acinetobacter baumannii as two representative OPs that colonize hot water plumbing, in tests using polyvinylchloride (PVC), copper-PVC, and iron-PVC convectively-mixed pipe reactors (CMPRs). Pipe materials vulnerable to corrosion (i.e., iron and copper) altered the pH, dissolved oxygen, and disinfectant levels in a manner that influenced growth trends of the two OPs and total bacteria. P. aeruginosa grew well in PVC CMPRs, poorly in iron-PVC CMPRs, and was best controlled by CSI disinfection, whereas A. baumannii showed the opposite trend for pipe material and was better controlled by chlorine and chlorine dioxide. Various scenarios were identified in which pipe material and disinfectant can interact to either hinder or accelerate growth of OPs, illustrating the difficulties of controlling OPs in portions of plumbing systems experiencing warm, stagnant water.
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OBJECTIVES: Reports of unsafe school drinking water in the United States highlight the importance of ensuring school water is safe for consumption. Our objectives were to describe (1) results from our recent school drinking water sampling of 5 common contaminants, (2) school-level factors associated with exceedances of various water quality standards, and (3) recommendations. METHODS: We collected and analyzed drinking water samples from at least 3 sources in 83 schools from a representative sample of California public schools from 2017 through 2022. We used multivariate logistic regression to examine school-level factors associated with lead in drinking water exceedances at the American Academy of Pediatrics (AAP) recommendation level (1 part per billion [ppb]) and state action-level exceedances of other contaminants (lead, copper, arsenic, nitrate, and hexavalent chromium). RESULTS: No schools had state action-level violations for arsenic or nitrate; however, 4% had ≥1 tap that exceeded either the proposed 10 ppb action level for hexavalent chromium or the 1300 ppb action level for copper. Of first-draw lead samples, 4% of schools had ≥1 tap that exceeded the California action level of 15 ppb, 18% exceeded the US Food and Drug Administration (FDA) bottled water standard of 5 ppb, and 75% exceeded the AAP 1 ppb recommendation. After turning on the tap and flushing water for 45 seconds, 2%, 10%, and 33% of schools exceeded the same standards, respectively. We found no significant differences in demographic characteristics between schools with and without FDA or AAP exceedances. CONCLUSIONS: Enforcing stricter lead action levels (<5 ppb) will markedly increase remediation costs. Continued sampling, testing, and remediation efforts are necessary to ensure drinking water meets safety standards in US schools.
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Plomo , Centers for Disease Control and Prevention, U.S. , Estados Unidos , Plomo/sangre , HumanosRESUMEN
Hot water building plumbing systems are vulnerable to the proliferation of opportunistic pathogens (OPs), including Legionella pneumophila and Mycobacterium avium. Implementation of copper as a disinfectant could help reduce OPs, but a mechanistic understanding of the effects on the microbial community under real-world plumbing conditions is lacking. Here, we carried out a controlled pilot-scale study of hot water systems and applied shotgun metagenomic sequencing to examine the effects of copper dose (0-2 mg/L), orthophosphate corrosion control agent, and water heater anode materials (aluminum vs magnesium vs powered anode) on the bulk water and biofilm microbiome composition. Metagenomic analysis revealed that, even though a copper dose of 1.2 mg/L was required to reduce Legionella and Mycobacterium numbers, lower doses (e.g., ≤0.6 mg/L) measurably impacted the broader microbial community, indicating that the OP strains colonizing these systems were highly copper tolerant. Orthophosphate addition reduced bioavailability of copper, both to OPs and to the broader microbiome. Functional gene analysis indicated that both membrane damage and interruption of nucleic acid replication are likely at play in copper inactivation mechanisms. This study identifies key factors (e.g., orthophosphate, copper resistance, and anode materials) that can confound the efficacy of copper for controlling OPs in hot water plumbing.
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Microbiota , Agua , Cobre , Metagenómica , Ingeniería Sanitaria , Electrodos , FosfatosRESUMEN
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments, such as freshwater, must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify the basic principles governing contractile vacuole function, we investigate here the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineages: the discoban Naegleria gruberi and the amoebozoan slime mold Dictyostelium discoideum. Using quantitative cell biology, we find that although these species respond differently to osmotic challenges, they both use vacuolar-type proton pumps for filling contractile vacuoles and actin for osmoregulation, but not to power water expulsion. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum. These analyses show that cytoplasmic pressure is sufficient to drive contractile vacuole emptying for a wide range of cellular pressures and vacuolar geometries. Because vacuolar-type proton-pump-dependent contractile vacuole filling and pressure-dependent emptying have now been validated in three eukaryotic lineages that diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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Dictyostelium , Citosol/metabolismo , Concentración Osmolar , Equilibrio Hidroelectrolítico , Vacuolas/metabolismo , Eucariontes , Agua/metabolismoRESUMEN
Copper (Cu) is sometimes applied as an antimicrobial for controlling Legionella in hot water plumbing systems, but its efficacy is inconsistent. Here we examined the effects of Cu (0 - 2 mg/L), orthophosphate corrosion inhibitor (0 or 3 mg/L as phosphate), and water heater anodes (aluminum, magnesium, and powered anodes) on both bulk water and biofilm-associated L. pneumophila in pilot-scale water heater systems. Soluble, but not total, Cu was a good predictor of antimicrobial capacity of Cu. Even after months of exposure to very high Cu levels (>1.2 mg/L) and low pH (<7), which increases solubility and enhances bioavailability of Cu, culturable L. pneumophila was only reduced by â¼1-log. Cu antimicrobial capacity was shown to be limited by various factors, including binding of Cu ions by aluminum hydroxide precipitates released from corrosion of aluminum anodes, higher pH due to magnesium anode corrosion, and high Cu tolerance of the outbreak-associated L. pneumophila strain that was inoculated into the systems. L. pneumophila numbers were also higher in several instances when Cu was dosed together with orthophosphate (e.g., with an Al anode), revealing at least one scenario where high levels of total Cu appeared to stimulate Legionella. The controlled, pilot-scale nature of this study provides new understanding of the limitations of Cu as an antimicrobial in real-world plumbing systems.
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Antiinfecciosos , Legionella pneumophila , Legionella , Cobre , Abastecimiento de Agua , Aluminio , Magnesio , Agua , Electrodos , Microbiología del AguaRESUMEN
Background: Exposure to waterborne lead during the Flint Water Crisis during April 2014-October 2015 is believed to have caused increased special education enrollment in Flint children. Method: This retrospective population-based cohort study utilized de-identified data for children under six years of age who had their blood lead tested during 2011 to 2019, and special education outcomes data for children enrolled in public schools for corresponding academic years (2011-12 to 2019-20) in Flint, Detroit (control city) and the State of Michigan. Trends in the following crisis-related covariates were also evaluated: waterborne contaminants, poverty, nutrition, city governance, school district policies, negative community expectations, media coverage and social media interactions. Results: Between 2011 and 2019, including the 2014-15 crisis period, the incidence of elevated blood lead in Flint children (≥ 5µg/dL) was always at least 47% lower than in the control city of Detroit (p < .0001) and was also never significantly higher than that for all children tested in Michigan (p = 0.33). Nonetheless, special education enrollment in Flint spiked relative to Detroit and Michigan (p < .0001). There is actually an inverse relationship between childhood blood lead and special education enrollment in Flint. Conclusion: This study failed to confirm any positive association between actual childhood blood lead levels and special education enrollment in Flint. Negative psychological effects associated with media predictions of brain damage could have created a self-fulfilling prophecy via a nocebo effect. The findings demonstrate a need for improved media coverage of complex events like the Flint Water Crisis.
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There is increased concern about perverse incentives, quantitative performance metrics, and hyper-competition for funding and faculty positions in US academia. Recipients of the prestigious National Science Foundation Graduate Research Fellowships (n = 244) from Civil and Environmental Engineering (45.5%) and Computer Science and Engineering (54.5%) were anonymously surveyed to create a baseline snapshot of their perceptions, behaviors and experiences. NSF Fellows ranked scientific advancement as the top metric for evaluating academics followed by publishing in high-impact journals, social impact of research, and publication/citation counts. The self-reported rate of academic cheating was 16.7% and of research misconduct was 3.7%. Thirty-one percent of fellows reported direct knowledge of graduate peers cheating, and 11.9% had knowledge of research misconduct by colleagues. Only 30.7% said they would report suspected misconduct. A majority of fellows (55.3%) felt that mandatory ethics trainings left them unprepared for dealing with ethical issues. Fellows stated academic freedom, flexible schedules and opportunity to mentor students were the most positive aspects of academia, whereas pressures for funding, publication, and tenure were cited as the most negative aspects. These data may be useful in considering how to better prepare STEM graduate trainees for academic careers.
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Mala Conducta Científica , Humanos , Motivación , Docentes , Ocupaciones , EstudiantesRESUMEN
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments like freshwater must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify basic principles governing contractile vacuole function, we here investigate the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineagesâ"the discoban Naegleria gruberi , and the amoebozoan slime mold Dictyostelium discoideum . Using quantitative cell biology we find that, although these species respond differently to osmotic challenges, they both use actin for osmoregulation, as well as vacuolar-type proton pumps for filling contractile vacuoles. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum . Because these three lineages diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
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BACKGROUND: Clinical practice characteristics and patient-reported outcomes for Ayurveda have not been adequately studied. METHODS: From January 2 thru February 28, 2022, all clients first seen during the 9-year period ending December 31, 2021, were solicited to respond to a web-based 34-item questionnaire containing 5 items targeting their general experience, 7 focusing on specific results, and 22 examining the implementation and impact of common Ayurvedic recommendations. These data were combined with practice data to develop linear regression models for the main outcome variables to assess improvement and the drivers of change. RESULTS: 170 responses were received from 252 eligible clients: an overall response rate of 67%. Test-retest data for 57 respondents gave a reliability coefficient of 0.83 [0.69-0.91]. The outcomes of consultation were independent of the mode of interaction (in-person vs. telehealth) and whether pulse diagnosis information was available. 85% were at least Satisfied with their overall consultation experience. The mean difference in health from before consultation to the survey was 1.2 [1.0-1.4] on a 7-point scale. 61% reported Much to Exceptional benefit. On average, 63% rated themselves as at least Somewhat Better in terms of physical well-being, emotional well-being, sleep, digestion, bowel function, fitness and energy. These findings were buttressed by clinically significant changes on 4 clinical assessment questionnaires among 60 clients. Engaging in follow-up and adopting recommendations were associated with better outcomes. CONCLUSIONS: Consultation with a practitioner of Ayurveda may provide substantial probability of durable holistic health benefit and improvement in chronic conditions with minimal risk of harm.
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Ejercicio Físico , Medición de Resultados Informados por el Paciente , Humanos , Reproducibilidad de los ResultadosRESUMEN
After a utility switched its source water from ground to surface water in 2017, first draw water lead levels spiked due to increased lead solder corrosion that could not be explained by existing knowledge. When lead release was not adequately reduced with a 90:10 orthophosphate/polyphosphate corrosion inhibitor blend or even high levels of 100% orthophosphate, an in-depth investigation of possible causes revealed a strong correlation between 90th percentile lead and seasonal fluctuations in surface water nitrate levels. Complementary bench-scale studies that tested new copper coupons with lead solder and harvested pipes from a worst case home verified a strong relationship between nitrate and elevated lead. Lead release in the presence of nitrate became increasingly erratic with time, resulting in the spalling of large lead solder particulates up to 7 mm in length into the water. Lead levels were occasionally >1000 ppb in homes and >100000 ppb in the bench experiments with harvested pipe. Orthophosphate was unable to sufficiently reduce lead levels below the action level during periods with high nitrate levels in the bench studies. Water utilities and regulators should proactively consider possible unintended consequences of higher nitrate levels on lead release when changing source waters or during seasonal runoff events.