811 research outputs found

    Microplastic moves pollutants and additives to worms, reducing functions linked to health and biodiversity.

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    PublishedJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.Inadequate products, waste management, and policy are struggling to prevent plastic waste from infiltrating ecosystems [1, 2]. Disintegration into smaller pieces means that the abundance of micrometer-sized plastic (microplastic) in habitats has increased [3] and outnumbers larger debris [2, 4]. When ingested by animals, plastic provides a feasible pathway to transfer attached pollutants and additive chemicals into their tissues [5-15]. Despite positive correlations between concentrations of ingested plastic and pollutants in tissues of animals, few, if any, controlled experiments have examined whether ingested plastic transfers pollutants and additives to animals. We exposed lugworms (Arenicola marina) to sand with 5% microplastic that was presorbed with pollutants (nonylphenol and phenanthrene) and additive chemicals (Triclosan and PBDE-47). Microplastic transferred pollutants and additive chemicals into gut tissues of lugworms, causing some biological effects, although clean sand transferred larger concentrations of pollutants into their tissues. Uptake of nonylphenol from PVC or sand reduced the ability of coelomocytes to remove pathogenic bacteria by >60%. Uptake of Triclosan from PVC diminished the ability of worms to engineer sediments and caused mortality, each by >55%, while PVC alone made worms >30% more susceptible to oxidative stress. As global microplastic contamination accelerates, our findings indicate that large concentrations of microplastic and additives can harm ecophysiological functions performed by organisms.Work was funded by Leverhulme Trust (grant F/00/568/C) to R.C.T., T.S.G., and S.J.R. During preparation of manuscript, M.A.B. was supported as a Postdoctoral Fellow at NCEAS, a center funded by the NSF (grant number EF-0553768), UCSB, with support from Ocean Conservancy

    Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life

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    publisher: Elsevier articletitle: Relative importance of microplastics as a pathway for the transfer of hydrophobic organic chemicals to marine life journaltitle: Environmental Pollution articlelink: http://dx.doi.org/10.1016/j.envpol.2016.09.046 content_type: article copyright: © 2016 Published by Elsevier Ltd

    Spectral and chromatographic characterisation of the onoceroid, ambrane: A potential novel biological marker

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    publisher: Elsevier articletitle: Spectral and chromatographic characterisation of the onoceroid, ambrane: A potential novel biological marker journaltitle: Organic Geochemistry articlelink: http://dx.doi.org/10.1016/j.orggeochem.2016.10.007 content_type: article copyright: © 2016 Elsevier Ltd. All rights reserved

    Biosynthesis of ambrein in ambergris: evidence from isotopic data and identification of possible intermediates

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    Ambrein is found in ambergris, a coprolith occurring in the rectum of the sperm whale. In vitro, ambrein is produced by enzymatic cyclisation of squalene, via a monocyclic intermediate. However, little is known of the in vivo process. In order to find evidence for the reaction in vivo, a comparison was made of the δ13C relative isotopic ratios of ambrein in ambergris with those of co-occurring sterols. A statistically significant difference was noted. This suggests that ambrein originates via a different biosynthetic mechanism from that of the sterols. Examination of the minor constituents of a hydrogenolysed extract of ambergris revealed compounds with a bicyclic polypodane nucleus, rather than those with monocyclic structures. It is hypothesised that in vivo biosynthesis of ambrein proceeds, at least in some cases, via bacterial production of bicyclic polypodenols. The latter are known products of non-concerted squalene (or squalene oxide) cyclisations in other organisms

    The age of ambergris.

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    Ambergris, which is a coprolith originating from the sperm whale, has been found only rarely, but for centuries, as jetsam on beaches all over the world. There are no reliable data indicating how long such samples may have remained at sea, with unsubstantiated accounts suggesting maybe decades. Here, we obtained over forty jetsam samples, many collected on known dates, from mostly known beach locations across the globe. Such an inventory of verified jetsam ambergris is unprecedented. Each sample was characterised by analytical methods such as gas chromatography-mass spectrometry (GC-MS). We then determined the radiocarbon ages of some of the samples by well-described accelerator-MS techniques. Surprisingly, some samples of jetsam have remained in the environment for about a thousand years

    Non-destructive dose verification of two drugs within 3D printed polyprintlets

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    Three-dimensional printing (3DP) is a revolutionary technology in pharmaceuticals, enabling the personalisation of flexible-dose drug products and 3D printed polypills (polyprintlets). A major barrier to entry of this technology is the lack of non-destructive quality control methods capable of verifying the dosage of multiple drugs in polyprintlets at the point of dispensing. In the present study, 3D printed films and cylindrical polyprintlets were loaded with flexible, therapeutic dosages of two distinct drugs (amlodipine and lisinopril) across concentration ranges of 1–5% w/w and 2–10% w/w, respectively. The polyprintlets were non-destructively analysed for dose content using a portable near infrared (NIR) spectrometer and validated calibration models were developed using partial least squares (PLS) regression, which showed excellent linearity (R2 Pred = 0.997, 0.991), accuracy (RMSEP = 0.24%, 0.24%) and specificity (LV1 = 82.77%, 79.55%) for amlodipine and lisinopril, respectively. X-ray powder diffraction (XRPD) and thermogravimetric analysis (TGA) showed that sintering partially transformed the phase of both drugs from the crystalline to amorphous forms. For the first time, we report a non-destructive method for quality control of two separate active ingredients in a single 3D printed drug product using NIR spectroscopy, overcoming a major barrier to the integration of 3D printing into clinical practice

    Releasing fast and slow: Non-destructive prediction of density and drug release from SLS 3D printed tablets using NIR spectroscopy

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    Selective laser sintering (SLS) 3D printing is a revolutionary 3D printing technology that has been found capable of creating drug products with varied release profiles by changing the laser scanning speed. Here, SLS 3D printed formulations (printlets) loaded with a narrow therapeutic index drug (theophylline) were produced using SLS 3D printing at varying laser scanning speeds (100–180 mm/s). The use of reflectance Fourier Transform – Near Infrared (FT-NIR) spectroscopy was evaluated as a non-destructive approach to predicting 3D printed tablet density and drug release at 2 h and 4 h. The printed drug products formulated with a higher laser speed exhibited an accelerated drug release and reduced density compared with the slower laser scanning speeds. Univariate calibration models were developed based on a baseline shift in the spectra in the third overtone region upon changing physical properties. For density prediction, the developed univariate model had high linearity (R2 value = 0.9335) and accuracy (error 50) for all of the test printlets. Overall, this article demonstrates the feasibility of SLS 3D printing to produce drug products containing a narrow therapeutic index drug across a range of drug release profiles, as well as the potential for FT-NIR spectroscopy to predict the physical characteristics of SLS 3D printed drug products (drug release and density) as a non-destructive quality control method at the point-of-care

    Do topical repellents divert mosquitoes within a community? Health equity implications of topical repellents as a mosquito bite prevention tool.

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    OBJECTIVES: Repellents do not kill mosquitoes--they simply reduce human-vector contact. Thus it is possible that individuals who do not use repellents but dwell close to repellent users experience more bites than otherwise. The objective of this study was to measure if diversion occurs from households that use repellents to those that do not use repellents. METHODS: The study was performed in three Tanzanian villages using 15%-DEET and placebo lotions. All households were given LLINs. Three coverage scenarios were investigated: complete coverage (all households were given 15%-DEET), incomplete coverage (80% of households were given 15%-DEET and 20% placebo) and no coverage (all households were given placebo). A crossover study design was used and coverage scenarios were rotated weekly over a period of ten weeks. The placebo lotion was randomly allocated to households in the incomplete coverage scenario. The level of compliance was reported to be close to 100%. Mosquito densities were measured through aspiration of resting mosquitoes. Data were analysed using negative binomial regression models. FINDINGS: Repellent-users had consistently fewer mosquitoes in their dwellings. In villages where everybody had been given 15%-DEET, resting mosquito densities were fewer than half that of households in the no coverage scenario (Incidence Rate Ratio [IRR]=0.39 (95% confidence interval [CI]: 0.25-0.60); p<0.001). Placebo-users living in a village where 80% of the households used 15%-DEET were likely to have over four-times more mosquitoes (IRR=4.17; 95% CI: 3.08-5.65; p<0.001) resting in their dwellings in comparison to households in a village where nobody uses repellent. CONCLUSIONS: There is evidence that high coverage of repellent use could significantly reduce man-vector contact but with incomplete coverage evidence suggests that mosquitoes are diverted from households that use repellent to those that do not. Therefore, if repellents are to be considered for vector control, strategies to maximise coverage are required
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