736 research outputs found
Plasticizer degradation by marine bacterial isolates : a proteogenomic and metabolomic characterization
Many commercial plasticizers are toxic endocrine-disrupting chemicals that are added to plastics during manufacturing and may leach out once they reach the environment. Traditional phthalic acid ester plasticizers (PAEs), such as dibutyl phthalate (DBP) and bis(2-ethyl hexyl) phthalate (DEHP), are now increasingly being replaced with more environmentally friendly alternatives, such as acetyl tributyl citrate (ATBC). While the metabolic pathways for PAE degradation have been established in the terrestrial environment, to our knowledge, the mechanisms for ATBC biodegradation have not been identified previously and plasticizer degradation in the marine environment remains underexplored. From marine plastic debris, we enriched and isolated microbes able to grow using a range of plasticizers and, for the first time, identified the pathways used by two phylogenetically distinct bacteria to degrade three different plasticizers (i.e., DBP, DEHP, and ATBC) via a comprehensive proteogenomic and metabolomic approach. This integrated multi-OMIC study also revealed the different mechanisms used for ester side-chain removal from the different plasticizers (esterases and enzymes involved in the β-oxidation pathway) as well as the molecular response to deal with toxic intermediates, that is, phthalate, and the lower biodegrading potential detected for ATBC than for PAE plasticizers. This study highlights the metabolic potential that exists in the biofilms that colonize plastics-the Plastisphere-to effectively biodegrade plastic additives and flags the inherent importance of microbes in reducing plastic toxicity in the environment
Bone Microarchitecture and Strength Adaptation to Physical Activity: A Within-Subject Controlled, HRpQCT Study
Purpose
Physical activity benefits bone mass and cortical bone size. The current study assessed the impact of chronic (≥10 years) physical activity on trabecular microarchitectural properties and micro-finite element (μFE) analyses of estimated bone strength.
Methods
Female collegiate-level tennis players (n=15; age=20.3±0.9 yrs) were used as a within-subject controlled model of chronic unilateral upper-extremity physical activity. Racquet-to-nonracquet arm differences at the distal radius and radial diaphysis were assessed using high-resolution peripheral computed tomography (HRpQCT). The distal tibia and tibial diaphysis in both legs were also assessed, and cross-country runners (n=15; age=20.8±1.2 yrs) included as controls.
Results
The distal radius of the racquet arm had 11.8% (95% confidence interval [CI], 7.9 to 15.7%) greater trabecular bone volume/tissue volume, with trabeculae that were greater in number, thickness, connectivity, and proximity to each other than in the nonracquet arm (all p<0.01). Combined with enhanced cortical bone properties, the microarchitectural advantages at the distal radius contributed a 18.7% (95% CI, 13.0 to 24.4%) racquet-to-nonracquet arm difference in predicted load before failure. At the radial diaphysis, predicted load to failure was 9.6% (95% CI, 6.7 to 12.6%) greater in the racquet vs. nonracquet arm. There were fewer and smaller side-to-side differences at the distal tibia; however, the tibial diaphysis in the leg opposite the racquet arm was larger with a thicker cortex and had 4.4% (95% CI, 1.7 to 7.1%) greater strength than the contralateral leg.
Conclusion
Chronically elevated physical activity enhances trabecular microarchitecture and μFE estimated strength, furthering observations from short-term longitudinal studies. The data also demonstrate tennis players exhibit crossed symmetry wherein the leg opposite the racquet arm possesses enhanced tibial properties compared to in the contralateral leg
Clinical relevance and validity of tools to predict infant, childhood and adulthood obesity: a systematic review
To determine the global availability of a multicomponent tool predicting overweight/obesity in infancy, childhood, adolescence or adulthood; and to compare their predictive validity and clinical relevance.Design/SettingThe PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. The databases PubMed, EMBASE, CINAHL, Web of Science and PsycINFO were searched. Additional articles were identified via reference lists of included articles. Risk of bias was assessed using the Academy of Nutrition and Dietetics' Quality Criteria Checklist. The National Health and Medical Research Council's Levels of Evidence hierarchy was used to assess quality of evidence. Predictive performance was evaluated using the ABCD framework.Eligible studies: tool could be administered at any life stage; quantified the risk of overweight/obesity onset; used more than one predictor variable; and reported appropriate prediction statistical outcomes.Of the initial 4490 articles identified, twelve articles (describing twelve tools) were included. Most tools aimed to predict overweight and/or obesity within childhood (age 2-12 years). Predictive accuracy of tools was consistently adequate; however, the predictive validity of most tools was questioned secondary to poor methodology and statistical reporting. Globally, five tools were developed for dissemination into clinical practice, but no tools were tested within a clinical setting.To our knowledge, a clinically relevant and highly predictive overweight/obesity prediction tool is yet to be developed. Clinicians can, however, act now to identify the strongest predictors of future overweight/obesity. Further research is necessary to optimise the predictive strength and clinical applicability of such a tool
Microbial pioneers of plastic colonisation in coastal seawaters
Plastics, when entering the environment, are immediately colonised by microorganisms. This modifies their physico-chemical properties as well as their transport and fate in natural ecosystems, but whom pioneers this colonisation in marine ecosystems? Previous studies have focused on microbial communities that develop on plastics after relatively long incubation periods (i.e., days to months), but very little data is available regarding the earliest stages of colonisation on buoyant plastics in marine waters (i.e., minutes or hours). We conducted a preliminary study where the earliest hours of microbial colonisation on buoyant plastics in marine coastal waters were investigated by field incubations and amplicon sequencing of the prokaryotic and eukaryotic communities. Our results show that members of the Bacteroidetes group pioneer microbial attachment to plastics but, over time, their presence is masked by other groups - Gammaproteobacteria at first and later by Alphaproteobacteria. Interestingly, the eukaryotic community on plastics exposed to sunlight became dominated by phototrophic organisms from the phylum Ochrophyta, diatoms at the start and brown algae towards the end of the three-day incubations. This study defines the pioneering microbial community that colonises plastics immediately when entering coastal marine environments and that may set the seeding Plastisphere of plastics in the oceans. [Abstract copyright: Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.
Vitamin D status and its consequences for health in South Africa
In this review, reports were retrieved in which vitamin D status, as assessed by serum
25-hydroxyvitamin D [25(OH)D] levels, was measured in South African population groups with
varied skin colours and ethnicities. Healthy children and adults were generally vitamin D-sufficient
[25(OH)D level >50 nmol/L] but the majority of those aged above 65 years were deficient. A major
role for exposure to solar ultraviolet radiation (UVR) in determining 25(OH)D levels was apparent,
with the dietary contribution being minor. Limited data exist regarding the impact of recent
changes in lifestyles on vitamin D status, such as urbanisation. With regard to disease susceptibility,
11 of 22 relevant publications indicated association between low 25(OH)D levels and disease, with
deficiency most notably found in individuals with tuberculosis and HIV-1. Information on the
relationship between vitamin D receptor variants and ethnicity, disease or treatment response in the
South African population groups demonstrated complex interactions between genetics, epigenetics
and the environment. Whether vitamin D plays an important role in protection against the range
of diseases that currently constitute a large burden on the health services in South Africa requires
further investigation. Only then can accurate advice be given about personal sun exposure or dietary
vitamin D supplementation.Anna K. Coussens is supported by the Academy of Science of South Africa (Sydney Brenner
Fellowship), Medical Research Council of South Africa-SHIP-02-2013; Robert J. Wilkinson by the Wellcome Trust
Grants 084323 and 104893, Francis Crick Institute 10218, Medical Research Council of South Africa, National
Research Foundation of South Africa 96841 and US National Institutes of Health U19AI111276; Liza Bornman by
the Cancer Association of South Africa and the National Research Foundation of South Africa, Robyn M. Lucas by
an Australian National Health and Medical Research Council Senior Research Fellowship 1107343; and Caradee Y.
Wright by the Medical Research Council of South Africa and the National Research Foundation of South Africa.http://www.mdpi.com/journal/ijerpham2017Geography, Geoinformatics and Meteorolog
Nightingallery: theatrical framing and orchestration in participatory performance
The Nightingallery project encouraged participants to converse, sing, and perform with a musically responsive animatronic bird, playfully interacting with the character while members of the public could look on and observe. We used Nightingallery to frame an HCI investigation into how people would engage with one another when confronted with unfamiliar technologies in conspicuously public, social spaces. Structuring performances as improvisational street theatre, we styled our method of exhibiting the bird character. We cast ourselves in supporting roles as carnival barkers and minders of the bird, presenting him as if he were a fantastical creature in a fairground sideshow display, allowing him the agency to shape and maintain dialogues with participants, and positioning him as the focal character upon which the encounter was centred. We explored how the anthropomorphic nature of the bird itself, along with the cultural connotations associated with the carnival/sideshow tradition helped signpost and entice participants through the trajectory of their encounters with the exhibit. Situating ourselves as secondary characters within the narrative defining the performance/use context, our methods of mediation, observation, and evaluation were integrated into the performance frame. In this paper, we explore recent HCI theories in mixed reality performance to reflect upon how genre-based cultural connotations can be used to frame trajectories of experience, and how manipulation of roles and agency in participatory performance can facilitate HCI investigation of social encounters with playful technologies. © 2014 Springer-Verlag London
Microbial hitchhikers harbouring antimicrobial-resistance genes in the riverine plastisphere
Background: The widespread nature of plastic pollution has given rise to wide scientific and social concern regarding the capacity of these materials to serve as vectors for pathogenic bacteria and reservoirs for Antimicrobial Resistance Genes (ARG). In- and ex-situ incubations were used to characterise the riverine plastisphere taxonomically and functionally in order to determine whether antibiotics within the water influenced the ARG profiles in these microbiomes and how these compared to those on natural surfaces such as wood and their planktonic counterparts. Results: We show that plastics support a taxonomically distinct microbiome containing potential pathogens and ARGs. While the plastisphere was similar to those biofilms that grew on wood, they were distinct from the surrounding water microbiome. Hence, whilst potential opportunistic pathogens (i.e. Pseudomonas aeruginosa, Acinetobacter and Aeromonas) and ARG subtypes (i.e. those that confer resistance to macrolides/lincosamides, rifamycin, sulfonamides, disinfecting agents and glycopeptides) were predominant in all surface-related microbiomes, especially on weathered plastics, a completely different set of potential pathogens (i.e. Escherichia, Salmonella, Klebsiella and Streptococcus) and ARGs (i.e. aminoglycosides, tetracycline, aminocoumarin, fluoroquinolones, nitroimidazole, oxazolidinone and fosfomycin) dominated in the planktonic compartment. Our genome-centric analysis allowed the assembly of 215 Metagenome Assembled Genomes (MAGs), linking ARGs and other virulence-related genes to their host. Interestingly, a MAG belonging to Escherichia –that clearly predominated in water– harboured more ARGs and virulence factors than any other MAG, emphasising the potential virulent nature of these pathogenic-related groups. Finally, ex-situ incubations using environmentally-relevant concentrations of antibiotics increased the prevalence of their corresponding ARGs, but different riverine compartments –including plastispheres– were affected differently by each antibiotic. Conclusions: Our results provide insights into the capacity of the riverine plastisphere to harbour a distinct set of potentially pathogenic bacteria and function as a reservoir of ARGs. The environmental impact that plastics pose if they act as a reservoir for either pathogenic bacteria or ARGs is aggravated by the persistence of plastics in the environment due to their recalcitrance and buoyancy. Nevertheless, the high similarities with microbiomes growing on natural co-occurring materials and even more worrisome microbiome observed in the surrounding water highlights the urgent need to integrate the analysis of all environmental compartments when assessing risks and exposure to pathogens and ARGs in anthropogenically-impacted ecosystems. 1SQe33MjkWBo3cdx_C_SmDVideo Abstrac
1 Versus 2-cm Excision Margins for pT2-pT4 Primary Cutaneous Melanoma (MelMarT): A Feasibility Study
Abstract
Background
There is a lack of consensus regarding optimal surgical excision margins for primary cutaneous melanoma > 1 mm in Breslow thickness (BT). A narrower surgical margin is expected to be associated with lower morbidity, improved quality of life (QoL), and reduced cost. We report the results of a pilot international study (MelMarT) comparing a 1 versus 2-cm surgical margin for patients with primary melanoma > 1 mm in BT.
Methods
This phase III, multicentre trial [NCT02385214] administered by the Australia & New Zealand Medical Trials Group (ANZMTG 03.12) randomised patients with a primary cutaneous melanoma > 1 mm in BT to a 1 versus 2-cm wide excision margin to be performed with sentinel lymph node biopsy. Surgical closure technique was at the discretion of the treating surgeon. Patients’ QoL was measured (FACT-M questionnaire) at baseline, 3, 6, and 12 months after randomisation.
Results
Between January 2015 and June 2016, 400 patients were randomised from 17 centres in 5 countries. A total of 377 patients were available for analysis. Primary melanomas were located on the trunk (56.9%), extremities (35.6%), and head and neck (7.4%). More patients in the 2-cm margin group required reconstruction (34.9 vs. 13.6%; p < 0.0001). There was an increased wound necrosis rate in the 2-cm arm (0.5 vs. 3.6%; p = 0.036). After 12 months’ follow-up, no differences were noted in QoL between groups.
Discussion
This pilot study demonstrates the feasibility of a large international RCT to provide a definitive answer to the optimal excision margin for patients with intermediate- to high-risk primary cutaneous melanoma.
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