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1.
J Physiol ; 602(10): 2169-2177, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38680058

RESUMEN

Type 1 diabetes mellitus (T1DM) refers to a metabolic condition where a lack of insulin impairs the usual homeostatic mechanisms to control blood glucose levels. Historically, participation in competitive sport has posed a challenge for those with T1DM, where the dynamic changes in blood glucose during exercise can result in dangerously high (hyperglycaemia) or low blood glucoses (hypoglycaemia) levels. Over the last decade, research and technological development has enhanced the methods of monitoring and managing blood glucose levels, thus reducing the chances of experiencing hyper- or hypoglycaemia during exercise. The introduction of continuous glucose monitoring (CGM) systems means that glucose can be monitored conveniently, without the need for frequent fingerpick glucose checks. CGM devices include a fine sensor inserted under the skin, measuring levels of glucose in the interstitial fluid. Readings can be synchronized to a reader or mobile phone app as often as every 1-5 min. Use of CGM devices is associated with lower HbA1c and a reduction in hypoglycaemic events, promoting overall health and athletic performance. However, there are limitations to CGM, which must be considered when being used by an athlete with T1DM. These limitations can be addressed by individualized education plans, using protective equipment to prevent sensor dislodgement, as well as further research aiming to: (i) account for disparities between CGM and true blood glucose levels during vigorous exercise; (ii) investigate the effects of temperature and altitude on CGM accuracy, and (iii) explore of the sociological impact of CGM use amongst sportspeople without diabetes on those with T1DM.


Asunto(s)
Atletas , Automonitorización de la Glucosa Sanguínea , Glucemia , Diabetes Mellitus Tipo 1 , Humanos , Diabetes Mellitus Tipo 1/sangre , Automonitorización de la Glucosa Sanguínea/instrumentación , Automonitorización de la Glucosa Sanguínea/métodos , Glucemia/análisis , Glucemia/metabolismo , Monitoreo Continuo de Glucosa
2.
Toxics ; 11(12)2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38133388

RESUMEN

Biofilms that colonize on the surface of microplastics (MPs) in freshwaters may pose a potential health risk. This study examined factors that influence MP-associated biofilm growth, including polymer type, degree of weathering, and source water quality. Weathered MPs produced in-lab were employed in biofilm trials conducted on site using a passive flow-through system with raw water at drinking water treatment facility intakes. Adenosine triphosphate (ATP) was used to quantify biofilm abundance; biofilm composition was assessed via metagenomic sequencing. Biofilm growth was observed on all polymer types examined and most prevalent on polyvinyl chloride (PVC), where ATP levels were 6 to 12 times higher when compared to other polymers. Pathogen-containing species including Salmonella enterica and Escherichia coli were present on all polymers with relative abundance up to 13.7%. S. enterica was selectively enriched on weathered MPs in specific water matrices. These findings support the need to research the potential accumulation of pathogenic organisms on microplastic surfaces.

3.
Polymers (Basel) ; 15(18)2023 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-37765530

RESUMEN

Microplastics and per- and polyfluoroalkyl substances (PFAS) both represent persistent groups of environmental contaminants that have been associated with human health risks. Microcystin toxins are produced and stored in the cells of cyanobacteria and may be released into sources of drinking water. Recent concerns have emerged regarding the ability of microplastics to adsorb a range of organic contaminants, including PFAS and microcystins. This study examined the adsorption of two long-chain and two short-chain PFAS, as well as two common microcystins, by both virgin and weathered microplastics in freshwater. Natural weathering of microplastic surfaces may decrease adsorption by introducing hydrophilic oxygen-containing functional groups. Up to 50% adsorption of perfluorooctanesulfonic acid (PFOS) was observed for virgin PVC compared to 38% for weathered PVC. In contrast, adsorption capacities for microcystins by virgin LDPE were approximately 5.0 µg/g whereas no adsorption was observed following weathering. These results suggest that adsorption is driven by specific polymer types and dominated by hydrophobic interactions. This is the first known study to quantify PFAS and microcystins adsorption when considering environmentally relevant concentrations as well as weathered microplastics.

4.
Sci Total Environ ; 884: 163722, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37116810

RESUMEN

To assess chloramine decay, this study compared the use of pipe loops, which incorporate continuously flowing water, to static pipe section reactors (PSRs). Unlined cast iron (UCI) and cement-lined ductile iron (CLDI) were harvested from distribution systems. These were directly compared to virgin polyvinyl chloride (PVC) pipe at low (0.03 m/s) and high (0.09 m/s) water velocities as well as hydraulic residence times (HRT) of 6 and 24 h. Pipe material was observed to exert the greatest impact on chloramine decay, followed by flow velocity. First-order decay coefficients obtained using pipe loops were statistically similar to those for PSR trials when considering UCI and CLDI pipe, irrespective of pipe velocity or water age. Overall results suggest that the use of PSRs may serve as a viable and cost-effective alternative to pipe loops for assessing the impact of operational variables on disinfectant decay.


Asunto(s)
Agua Potable , Abastecimiento de Agua , Cloraminas , Cloro , Hierro
5.
Pilot Feasibility Stud ; 9(1): 60, 2023 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-37072802

RESUMEN

BACKGROUND: Type 2 diabetes mellitus (T2DM) and its associated complications puts considerable strain on healthcare systems. With the global incidence of T2DM increasing, effective disease management is essential. Physical activity (PA) is a key component of T2DM management; however, rates of PA engagement are low in this population. Developing effective and sustainable interventions that encourage PA is a high priority. Electrically assisted bicycles are becoming increasingly popular and may increase PA in healthy adults. This study aimed to provide evidence of the feasibility of conducting a randomized controlled trial to evaluate the efficacy of an e-cycling intervention to increase PA and improve health in individuals with T2DM. METHODS: A parallel-group two-arm randomized, waitlist-controlled pilot study was conducted. Individuals were randomized to either an e-bike intervention or standard care. The intervention incorporated two one-to-one e-bike skills training and behavioural counselling sessions delivered by a community-based cycling charity, followed by a 12-week e-bike loan with two further sessions with the instructors. Feasibility was assessed via measures related to recruitment, retention and intervention implementation. Post-intervention interviews with instructors and participants explored the acceptability of the study procedures and intervention. Clinical, physiological and behavioural outcomes were collected at baseline and post-intervention to evaluate the intervention's potential. RESULTS: Forty participants (Mage = 57) were randomized, of which 34 were recruited from primary care practices. Thirty-five participants were retained in the trial. The intervention was conducted with high fidelity (> 80% content delivered). E-bike training provided participants with the skills, knowledge and confidence needed to e-bike independently. Instructors reported being more confident delivering the skills training than behavioural counselling, despite acknowledging its importance. The study procedures were found to be acceptable to participants. Between-group differences in change during the intervention were indicative of the interventions potential for improving glucose control, health-related quality of life and cardiorespiratory fitness. Increases in overall device measured moderate-to-vigorous PA behaviour following the intervention were found, and there was evidence that this population self-selected to e-cycle at a moderate intensity. CONCLUSIONS: The study's recruitment, retention, acceptability and potential efficacy support the development of a definitive trial subject to identified refinements. TRIAL REGISTRATION: ISRCTN, ISRCTN67421464 . Registered 17/12/2018.

6.
Polymers (Basel) ; 15(6)2023 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-36987112

RESUMEN

The occurrence of microplastics in drinking water has drawn increasing attention due to their ubiquity and unresolved implications regarding human health. Despite achieving high reduction efficiencies (70 to >90%) at conventional drinking water treatment plants (DWTPs), microplastics remain. Since human consumption represents a small portion of typical household water use, point-of-use (POU) water treatment devices may provide the additional removal of microplastics (MPs) prior to consumption. The primary objective of this study was to evaluate the performance of commonly used pour-through POU devices, including those that utilize combinations of granular activated carbon (GAC), ion exchange (IX), and microfiltration (MF), with respect to MP removal. Treated drinking water was spiked with polyethylene terephthalate (PET) and polyvinyl chloride (PVC) fragments, along with nylon fibers representing a range of particle sizes (30-1000 µm) at concentrations of 36-64 particles/L. Samples were collected from each POU device following 25, 50, 75, 100 and 125% increases in the manufacturer's rated treatment capacity, and subsequently analyzed via microscopy to determine their removal efficiency. Two POU devices that incorporate MF technologies exhibited 78-86% and 94-100% removal values for PVC and PET fragments, respectively, whereas one device that only incorporates GAC and IX resulted in a greater number of particles in its effluent when compared to the influent. When comparing the two devices that incorporate membranes, the device with the smaller nominal pore size (0.2 µm vs. ≥1 µm) exhibited the best performance. These findings suggest that POU devices that incorporate physical treatment barriers, including membrane filtration, may be optimal for MP removal (if desired) from drinking water.

7.
BMC Pediatr ; 23(1): 131, 2023 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-36949473

RESUMEN

BACKGROUND: Many children and adolescents with Type 1 Diabetes Mellitus (T1DM) don't meet the recommended levels of physical activity. Healthcare professionals (HCPs) have a key role in supporting and encouraging children and adolescents with T1DM to be physically active. This study aims to understand the perspectives of HCPs in relation to supporting physical activity and implementing guidelines relating to physical activity. METHODS: An online mixed methods survey was circulated to HCPs in pediatric diabetes units in England and Wales. Participants were asked about how they support physical activity in their clinic and their perceptions of barriers/enablers of providing physical activity support to children and adolescents with T1DM. Quantitative data were analysed descriptively. An deductive thematic approach was applied to the free text responses using the Capability Opportunity Motivation model of Behaviour (COM-B) as a framework. RESULTS: Responses were received from 114 individuals at 77 different pediatric diabetes units (45% of pediatric diabetes units in England and Wales). HCPs surveyed felt that the promotion of physical activity is important (90%) and advised patients to increase levels of physical activity (88%). 19% of the respondents felt they did not have sufficient knowledge to provide support. HCPs reported limited knowledge and confidence, time and resources as barriers to providing support. They also felt the current guidance was too complicated with few practical solutions. CONCLUSION: Pediatric HCPs need training and support to be able to encourage and support children and adolescents with T1D to be a physical activity. In addition, resources that provide simple and practical advice to manage glucose around exercise are needed.


Asunto(s)
Diabetes Mellitus Tipo 1 , Humanos , Niño , Adolescente , Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 1/complicaciones , Ejercicio Físico , Inglaterra , Gales , Personal de Salud/educación , Investigación Cualitativa
8.
Chemosphere ; 308(Pt 3): 136449, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36115477

RESUMEN

Microscopy is often the first step in microplastic analysis and is generally followed by spectroscopy to confirm material type. The value of microscopy lies in its ability to provide count, size, color, and morphological information to inform toxicity and source apportionment. To assess the accuracy and precision of microscopy, we conducted a method evaluation study. Twenty-two laboratories from six countries were provided three blind spiked clean water samples and asked to follow a standard operating procedure. The samples contained a known number of microplastics with different morphologies (fiber, fragment, sphere), colors (clear, white, green, blue, red, and orange), polymer types (PE, PS, PVC, and PET), and sizes (ranging from roughly 3-2000 µm), and natural materials (natural hair, fibers, and shells; 100-7000 µm) that could be mistaken for microplastics (i.e., false positives). Particle recovery was poor for the smallest size fraction (3-20 µm). Average recovery (±StDev) for all reported particles >50 µm was 94.5 ± 56.3%. After quality checks, recovery for >50 µm spiked particles was 51.3 ± 21.7%. Recovery varied based on morphology and color, with poorest recovery for fibers and the largest deviations for clear and white particles. Experience mattered; less experienced laboratories tended to report higher concentration and had a higher variance among replicates. Participants identified opportunity for increased accuracy and precision through training, improved color and morphology keys, and method alterations relevant to size fractionation. The resulting data informs future work, constraining and highlighting the value of microscopy for microplastics.


Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Humanos , Microscopía , Plásticos/análisis , Polímeros , Cloruro de Polivinilo/análisis , Agua/análisis , Contaminantes Químicos del Agua/análisis
9.
Environ Sci Technol ; 56(20): 14627-14639, 2022 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-36173153

RESUMEN

Increases in the global use of plastics have caused concerns regarding potential adverse effects on human health. Plastic products contain hundreds of potentially toxic chemical additives, yet the exact chemicals which drive toxicity currently remain unknown. In this study, we employed nontargeted analysis and in vitro bioassays to identify the toxicity drivers in plastics. A total of 56 chemical additives were tentatively identified in five commonly used plastic polymer pellets (i.e., PP, LDPE, HDPE, PET, and PVC) by employing suspect screening and nontargeted analysis. Phthalates and organophosphates were found to be dominant in PVC pellets. Triphenyl phosphate and 2-ethylhexyl diphenyl phosphate accounted for a high amount (53.6%) of the inhibition effect of PVC pellet extract on human carboxylesterase 1 (hCES1) activity. Inspired by the high abundances of chemical additives in PVC pellets, six different end-user PVC-based products including three widely used PVC water pipes were further examined. Among them, extracts of PVC pipe exerted the strongest PPARγ activity and cell viability suppression. Organotins were identified as the primary drivers to these in vitro toxicities induced by the PVC pipe extracts. This study clearly delineates specific chemical additives responsible for hCES1 inhibition, PPARγ activity, and cell viability suppression associated with plastic.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Hidrolasas de Éster Carboxílico , Humanos , Organofosfatos/toxicidad , PPAR gamma , Fosfatos , Plásticos/toxicidad , Polietileno , Cloruro de Polivinilo/toxicidad , Contaminantes Químicos del Agua/análisis
10.
Chemosphere ; 307(Pt 1): 135585, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35817185

RESUMEN

Concern exists regarding potential health impacts associated with contaminants of emerging concern (CECs) that adsorb to microplastics (MPs). Previous studies have examined MPs as potential contaminant vectors in marine environments as opposed to freshwaters that represent drinking water sources. This study examined adsorption of two polycyclic aromatic hydrocarbons (PAHs), phenanthrene and fluoranthene, by virgin and weathered polyethylene (PE) in both artificial and natural freshwater matrices. Adsorption kinetics and isotherms conducted in artificial freshwater (AFW) consistently showed higher adsorption onto smaller (200 µm) PE when compared to 1090 µm PE. Adsorption mechanisms were primarily associated with hydrophobic interactions and monolayer chemisorption. As well, environmental factors including dissolved organic matter (DOC), pH, and polymer weathering also impacted adsorption. This work provides new insights regarding the adsorption of organic pollutants to better understand the risk of MPs in drinking water sources.


Asunto(s)
Agua Potable , Contaminantes Ambientales , Fenantrenos , Hidrocarburos Policíclicos Aromáticos , Contaminantes Químicos del Agua , Adsorción , Contaminantes Ambientales/química , Fluorenos , Agua Dulce , Microplásticos , Fenantrenos/análisis , Plásticos/química , Hidrocarburos Policíclicos Aromáticos/análisis , Polietileno/química , Contaminantes Químicos del Agua/análisis
11.
Eur Urol Focus ; 8(1): 89-97, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-35101453

RESUMEN

Patients with nocturia are commonly referred to urology clinics, including many for whom a nonurological medical condition is responsible for their symptoms. The PLanning Appropriate Nocturia Evaluation and Treatment (PLANET) study was established to develop practical approaches to equip healthcare practitioners to deal with the diverse causes of nocturia, based on systematic reviews and expert consensus. Initial assessment and therapy need to consider the possibility of one or more medical conditions falling into the "SCREeN" areas of Sleep medicine (insomnia, periodic limb movements of sleep, parasomnias, and obstructive sleep apnoea), Cardiovascular (hypertension and congestive heart failure), Renal (chronic kidney disease), Endocrine (diabetes mellitus, thyroid disease, pregnancy/menopause, and diabetes insipidus), and Neurology. Medical and medication causes of xerostomia should also be considered. Some key indicators for these conditions can be identified in urology clinics, working in partnership with the primary care provider. Therapy of the medical condition in some circumstances lessens the severity of nocturia. However, in many cases there is a conflict between the two, in which case the medical condition generally takes priority on safety grounds. It is important to provide patients with a realistic expectation of therapy and awareness of limitations of current therapeutic options for nocturia. PATIENT SUMMARY: Nocturia is the symptom of waking at night to pass urine. Commonly, this problem is referred to urology clinics. However, in some cases, the patient does not have a urological condition but actually a condition from a different speciality of medicine. This article describes how best the urologist and the primary care doctor can work together to assess the situation and make sensible and safe treatment suggestions. Unfortunately, there is sometimes no safe or effective treatment choice for nocturia, and treatment needs to focus instead on supportive management of symptoms.


Asunto(s)
Hipertensión , Nocturia , Urología , Femenino , Humanos , Hipertensión/complicaciones , Nocturia/tratamiento farmacológico , Nocturia/terapia , Planetas , Resultado del Tratamiento
12.
Eur Urol Focus ; 8(1): 52-59, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34996740

RESUMEN

CONTEXT: Salt and water homeostasis is regulated hormonally, so polyuria can result from endocrine disease directly or via secondary effects. These mechanisms are not consistently considered in primary care management of nocturia. OBJECTIVE: To conduct a systematic review (SR) of nocturia in endocrine disease and reach expert consensus for primary care management. EVIDENCE ACQUISITION: Four databases were searched from January 2000 to April 2020. A total of 4382 titles and abstracts were screened, 36 studies underwent full-text screening, and 14 studies were included in the analysis. Expert and public consensus was achieved using the nominal group technique (NGT). EVIDENCE SYNTHESIS: Twelve studies focused on mechanisms of nocturia, while two evaluated treatment options; none of the studies took place in a primary care setting. NGT consensus identified key clinical evaluation themes, including the presence of thirst, a medical background of diabetes mellitus or insipidus, thyroid disease, oestrogen status, medications (fluid loss or xerostomia), and general examination including body mass index. Proposed investigations include a bladder diary, renal and thyroid function, calcium, and glycated haemoglobin. Morning urine osmolarity should be examined in the context of polyuria of >2.5 l/24 h persisting despite fluid advice, with urine concentration >600 mOsm/l after fluid restriction excluding diabetes insipidus. Treatment should involve education, including adjustment of lifestyle and medication where possible. Any underlying endocrine disorder should be managed according to local guidance. Referral to endocrinology is needed if there is hyperthyroidism, hyperparathyroidism, or morning urine osmolarity <600 mOsm/l after overnight fluid avoidance. CONCLUSIONS: Endocrine disease can result in nocturia via varied salt and water regulation pathways. The aim of management is to identify and treat causative factors, but secondary effects can restrict improvements in nocturia. PATIENT SUMMARY: People with altered hormone function can suffer from severe sleep disturbance because of a need to pass urine caused by problems in controlling water and salt levels. An expert panel recommended the best ways to assess and treat these problems on the basis of the rather small amount of up-to-date published research available.


Asunto(s)
Enfermedades del Sistema Endocrino , Nocturia , Consenso , Enfermedades del Sistema Endocrino/complicaciones , Humanos , Nocturia/diagnóstico , Poliuria/etiología , Atención Primaria de Salud , Agua
13.
Diabet Med ; 39(1): e14730, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34676911

RESUMEN

AIMS: Type 1 diabetes is characterised by the destruction of pancreatic ß-cells. Significant levels of ß-cells remain at diagnosis. Preserving these cells improves glucose control and protects from long-term complications. We undertook a systematic review and meta-analyses of all randomised controlled trials (RCTs) of interventions to preserve ß-cell function in people newly diagnosed with type 1 diabetes. This paper reports the results of interventions for improving glucose control to assess whether they preserve ß-cell function. METHODS: Searches for RCTs in MEDLINE, Embase, Cochrane CENTRAL, ClinicalTrials.gov and WHO International Clinical Trials Registry. Eligible studies included newly diagnosed patients with type 1 diabetes, any intervention to improve glucose control and at least 1 month of follow-up. Data were extracted using a pre-defined data-extraction sheet with 10% of extractions checked by a second reviewer. RESULTS: Twenty-eight studies with 1662 participants were grouped by intervention into six subgroups (alternative insulins, subcutaneous and intravenous insulin delivery, intensive therapy, glucose sensing, adjuncts). Only three studies demonstrated an improvement in glucose control as well as ß-cell function. These interventions included intensive insulin therapy and use of an alternative insulin. CONCLUSIONS: This is the largest comprehensive review of RCTs in this area. It demonstrates a lack of robust evidence that interventions to improve glucose control preserve ß-cell function in new onset type 1 diabetes, although analysis was hampered by low-quality evidence and inconsistent reporting of studies. Development of guidelines to support the design of trials in this field is a priority.


Asunto(s)
Glucemia/metabolismo , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Control Glucémico/normas , Células Secretoras de Insulina/metabolismo , Insulina/administración & dosificación , Diabetes Mellitus Tipo 1/sangre , Ayuno , Humanos , Hipoglucemiantes/administración & dosificación , Células Secretoras de Insulina/efectos de los fármacos
14.
Chemosphere ; 286(Pt 3): 131881, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34403902

RESUMEN

To date, no standardized methods have been proposed for conducting microplastic analyses in treated drinking waters, resulting in challenges associated with direct comparisons among studies. This study compares known methods for collecting and extracting microplastics from drinking waters: an in-laboratory (in-lab) filtration method and an in-line filtration method (i.e., water filtered on-site without an intermediate storage and/or transportation step). In-lab methods have been the predominant method for sample collection in drinking water matrices, and in-line methods are emerging due to the potential to sample large volumes of water on site and minimize contamination from airborne particles, but the two methods have yet to be directly compared using real samples. In response, this study evaluates both methods in terms of recovering spiked reference microplastics, collecting microplastics from tap water samples using the same water volume, and quantifying the removal of microplastics through a full-scale ultrafiltration system. In-line filtration was shown to have higher recoveries for all the reference microplastics examined (+37 % for PVC fragments, +23 % for PET fragments, +22 % for nylon fibers and +7 % for PET fibers) and a greater potential to reduce microplastic contamination. It also resulted in lower standard deviations for total microplastic counts in the tap water and UF influent and effluent samples. The filtration capacity of the proposed in-line filtration method could exceed 350 L of treated water, but this is highly dependent on the water quality. This study therefore supports the use of in-line filtration methods towards the standardization of microplastic collection procedures in drinking water.


Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Microplásticos , Plásticos , Contaminantes Químicos del Agua/análisis
15.
Chemosphere ; 288(Pt 2): 132587, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34662634

RESUMEN

This study examines the removal of microplastics and other anthropogenic particles (>10 µm) from surface water by a full-scale conventional drinking water treatment plant. The treatment process is composed of coagulation with aluminum hydroxide, flocculation, anthracite-sand filtration, and chlorination. Samples were also collected from pilot-scale biological filters consisting of anthracite-sand or granular activated carbon (GAC) media operated with or without pre-ozonation and at a range of different empty-bed contact times (EBCTs). Particles in 10 L water samples collected in duplicate using a fully enclosed sampling apparatus were separated using sieves with 500 µm, 300 µm, 125 µm, and 45 µm openings followed by filtration through 10 µm polycarbonate filters. Particles were counted using stereomicroscopy and characterized using µ-Raman spectroscopy. Full-scale conventional treatment removed 52 % of anthropogenic particles when comparing raw (42 ± 18 particles/L) and finished water (20 ± 8 particles/L). Coagulation, flocculation, and sedimentation accounted for the highest removal (70 %) of any individual unit process. Overall removal was reduced to 52 %, the difference being attributed to airborne particle deposition that occurred while water was detained in a clearwell (exposed to atmosphere via ventilation) that was used to achieve the required contact time for disinfection. The majority of the particles (>80 %) were identified as fibers 10-45 µm; microplastics were predominantly composed of polyester while the non-plastic anthropogenic particles were primarily cellulose. None of the pilot filter configurations examined resulted in significantly fewer microplastics when compared to full-scale conventional filtration. This study illustrates that the removal efficiency of conventional treatment may be limited when considering microfibers <45 µm in size.


Asunto(s)
Agua Potable , Purificación del Agua , Filtración , Microplásticos , Plásticos
16.
Water Res ; 205: 117636, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34555739

RESUMEN

Many water providers monitor adenosine triphosphate (ATP) as an indicator of biological acclimation of their biofilters; however, strong correlations between ATP concentration and filter performance (e.g., organic matter or disinfection by-product precursor removal) are not typically observed. As an alternative, this study evaluated the use of enzyme activity for monitoring biological processes within filters. Recent studies have proposed that enzyme activity may be used as an indicator of biofilter function as it provides a means to quantify biodegradation which may allow for a more accurate measure of degradation potential and to gain a better understanding of biofilter performance. Sampling was completed from full- and pilot-scale biofilters to assess impacts associated with pre-treatments, varying sources waters, as well as pre-treatment and operating conditions. Enzyme activity (carboxylic esterase, phosphatase, ß-glucosidase, α-glucosidase, ß-xylosidase, chitinase, and cellulase) and ATP were measured from the top 5 cm of biofilter media representative of typical full-scale sampling; water quality parameters included dissolved organic carbon (DOC) and disinfection by-products (DBPs): trihalomethane (THM) formation potential (FP), and haloacetic acid FP (HAA FP). Results confirmed that ATP was not a reliable monitoring tool for DOC and DBP FP reduction in biofilters. A strong relationship was observed between esterase activity and DOC reduction; chitinase activity significantly correlated to THM FP reduction for filters treating three different source waters and HAA FP reduction achieved by filters treating the same source water with a range of pre-treatment and backwash conditions. This study showed that enzyme activity may be appropriate for monitoring biological processes within drinking water filters and may act as a surrogate for the removal of organic compounds.


Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Purificación del Agua , Desinfección , Agua Potable/análisis , Filtración , Trihalometanos , Contaminantes Químicos del Agua/análisis
17.
J Endocr Soc ; 5(10): bvab127, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34377883

RESUMEN

CONTEXT: High-residual C-peptide in longer-duration type 1 diabetes (T1D) is associated with fewer hypoglycemic events and reduced glycemic variability. Little is known about the impact of C-peptide close to diagnosis. OBJECTIVE: Using continuous glucose monitoring (CGM) data from a study of newly diagnosed adults with T1D, we aimed to explore if variation in C-peptide close to diagnosis influenced glycemic variability and risk of hypoglycemia. METHODS: We studied newly diagnosed adults with T1D who wore a Dexcom G4 CGM for 7 days as part of the Exercise in Type 1 Diabetes (EXTOD) study. We examined the relationship between peak stimulated C-peptide and glycemic metrics of variability and hypoglycemia for 36 CGM traces from 23 participants. RESULTS: For every 100 pmol/L-increase in peak C-peptide, the percentage of time spent in the range 3.9 to 10 mmol/L increased by 2.4% (95% CI, 0.5-4.3), P = .01) with a reduction in time spent at level 1 hyperglycemia (> 10 mmol/L) and level 2 hyperglycemia (> 13.9 mmol/L) by 2.6% (95% CI, -4.9 to -0.4, P = .02) and 1.3% (95% CI, -2.7 to -0.006, P = .04), respectively. Glucose levels were on average lower by 0.19 mmol/L (95% CI, -0.4 to 0.02, P = .06) and SD reduced by 0.14 (95% CI, -0.3 to -0.02, P = .02). Hypoglycemia was not common in this group and no association was observed between time spent in hypoglycemia (P = .97) or hypoglycemic risk (P = .72). There was no association between peak C-peptide and insulin dose-adjusted glycated hemoglobin A1c (P = .45). CONCLUSION: C-peptide is associated with time spent in the normal glucose range and with less hyperglycemia, but not risk of hypoglycemia in newly diagnosed people with T1D.

18.
Appl Spectrosc ; 74(9): 1099-1125, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32643389

RESUMEN

Plastic pollution is a defining environmental contaminant and is considered to be one of the greatest environmental threats of the Anthropocene, with its presence documented across aquatic and terrestrial ecosystems. The majority of this plastic debris falls into the micro (1 µm-5 mm) or nano (1-1000 nm) size range and comes from primary and secondary sources. Its small size makes it cumbersome to isolate and analyze reproducibly, and its ubiquitous distribution creates numerous challenges when controlling for background contamination across matrices (e.g., sediment, tissue, water, air). Although research on microplastics represents a relatively nascent subfield, burgeoning interest in questions surrounding the fate and effects of these debris items creates a pressing need for harmonized sampling protocols and quality control approaches. For results across laboratories to be reproducible and comparable, it is imperative that guidelines based on vetted protocols be readily available to research groups, many of which are either new to plastics research or, as with any new subfield, have arrived at current approaches through a process of trial-and-error rather than in consultation with the greater scientific community. The goals of this manuscript are to (i) outline the steps necessary to conduct general as well as matrix-specific quality assurance and quality control based on sample type and associated constraints, (ii) briefly review current findings across matrices, and (iii) provide guidance for the design of sampling regimes. Specific attention is paid to the source of microplastic pollution as well as the pathway by which contamination occurs, with details provided regarding each step in the process from generating appropriate questions to sampling design and collection.


Asunto(s)
Monitoreo del Ambiente/métodos , Contaminantes Ambientales , Microplásticos , Control de Calidad , Manejo de Especímenes/métodos , Contaminantes Ambientales/análisis , Contaminantes Ambientales/aislamiento & purificación , Guías como Asunto , Microplásticos/análisis , Microplásticos/aislamiento & purificación
19.
Water Res ; 183: 116069, 2020 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-32668352

RESUMEN

"Effective Enzyme Activity", or simply "Effective Activity", is proposed as a biofiltration monitoring tool which combines enzyme activity with empty bed contact time (EBCT) to quantify biodegradation potential. The primary objective of this study was to evaluate the applicability of the Effective Activity concept for predicting water quality in biofiltration systems. This pilot-scale study evaluated eight different biofilter configurations in order to quantify impacts associated with filter media (anthracite/sand or granular activated carbon), pre-treatment (settled water with or without ozonation) and operating conditions (15- and 30-min EBCT, and backwash with or without chlorine). Microbial characterization included biomass concentration, as measured by adenosine triphosphate (ATP), in addition to esterase and phosphatase activity. Water quality parameters included dissolved organic carbon (DOC), trihalomethane (THM) formation potential (FP), haloacetic acid (HAA) FP, haloacetonitrile (HAN) FP, iodinated DBP FP (THMs and HAAs) and inorganic nutrients (phosphorus and nitrogen). Results confirmed the benefits to treated water quality associated with the application of an ozone residual of 0.5 mg/L, utilization of GAC filter media, eliminating chlorinated backwash, and extending EBCT. This study demonstrated a good relationship between effective esterase activity and reductions in DOC and THM FP, including those systems which incorporate pre-ozonation. As such, this study showed that Effective Activity may be appropriate for relating biomass characterization to treated water quality and highlights the importance of quantifying biomass activity in addition to quantity.


Asunto(s)
Ozono , Contaminantes Químicos del Agua/análisis , Purificación del Agua , Desinfección , Filtración , Trihalometanos
20.
Water Res ; 174: 115641, 2020 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-32120068

RESUMEN

Previous studies have reported that biofilm extracted from full-scale biofilters can serve as nitrogenous disinfection by-product (N-DBP) precursors. Detached biofilm materials could escape during filter ripening and form N-DBP upon chloramination. This study examined the potential breakthrough of biofilm and N-DBP precursors during filter ripening at two water treatment plants (WTPs). The presence of biofilm material in aqueous samples was estimated by total adenosine triphosphate (tATP) levels; N-DBP formation potential (FP) tests were conducted under uniform formation conditions to quantify N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) precursors. While tATP peaks in filter effluent were observed post backwash at both WTPs, temporary increases of effluent NDMA FP were only observed during filter ripening where particle-associated NDMA precursors served as the dominant contributor. Overall, biofilters examined in this study demonstrated a consistent removal of NDMA FP regardless of the filter ripening process.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Dimetilnitrosamina , Desinfección , Nitrógeno
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