277 research outputs found

    Environmental and economic evaluation of supply loops and their constraints

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Production, use, and fate of all plastics ever made

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 3 (2017): e1700782, doi:10.1126/sciadv.1700782.Plastics have outgrown most man-made materials and have long been under environmental scrutiny. However, robust global information, particularly about their end-of-life fate, is lacking. By identifying and synthesizing dispersed data on production, use, and end-of-life management of polymer resins, synthetic fibers, and additives, we present the first global analysis of all mass-produced plastics ever manufactured. We estimate that 8300 million metric tons (Mt) as of virgin plastics have been produced to date. As of 2015, approximately 6300 Mt of plastic waste had been generated, around 9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment. If current production and waste management trends continue, roughly 12,000 Mt of plastic waste will be in landfills or in the natural environment by 2050.R.G. was supported by the NSF Chemical, Bioengineering, Environmental and Transport Systems grant #1335478

    Life Cycle Aware Computing: Reusing Silicon Technology

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    Despite the high costs associated with processor manufacturing, the typical chip is used for only a fraction of its expected lifetime. Reusing processors would create a food chain of electronic devices that amortizes the energy required to build chips over several computing generations

    Korištenje Lewisovih stanica u istraživanju enzimske kinetike (S)-hidroksinitril liaze u dvofaznom sustavu

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    (S)-Hydroxynitrile lyase from Hevea brasiliensis (HbHnl) (EC 4.1.2.39) catalyzes the reversible synthesis of chiral cyanohydrins from aldehydes or ketones and HCN. The enzymatic formation of (S)-mandelonitrile (MN) from benzaldehyde (BA) and HCN was studied in two-phase systems of buffer and organic solvents (diisopropyl ether, methyl-t-butyl ether) using a Lewis cell to investigate the interaction between mass transfer and the biocatalytic reaction. The enzymatic reaction rate in the aqueous phase saturated with organic solvents is drastically reduced in comparison to pure buffer due to the increase of the Michaelis-Menten constants of the substrates. Mass transfer of the substrates from the organic to the aqueous phase and mass transfer of the product in the opposite direction could be described by the two-film theory. The formation of (S)-mandelonitrile in the Lewis cell follows an aqueous phase distributed reaction model, which means that the enzymatic reaction takes place in the bulk of the aqueous phase and in the thin film close to the interface and/or directly at the interface. Using the Hatta number it could be shown that the mass transfer of benzaldehyde from the organic to the aqueous phase is enhanced by the biocatalytic reaction of the (S)-hydroxynitrile lyase from Hevea brasiliensis.(S)-hidroksinitril liaza iz Hevea brasiliensis (HbHnl) (EC 4.1.2.39) katalizira reverzibilnu sintezu kiralnih cianohidrina iz aldehida ili ketona i HCN. Enzimska sinteza (S)-mandelonitrila (MN) iz benzaldehida (BA) i HCN ispitivana je u dvofaznim sustavima pufera i organskih otapala (diizopropileter, metil-t-butileter) koristeći Lewisovu stanicu kako bi se istražilo međudjelovanje prijenosa mase i biokatalitičke reakcije. Brzina enzimske reakcije u vodenoj fazi, zasićenoj organskim otapalima, drastično je smanjena u usporedbi s reakcijom u čistom puferu zbog povišenja Michaelis-Mentenove š konstante supstrata. Prijenos mase supstrata iz organske u vodenu fazu te prijenos mase produkta u suprotnom smjeru može se opisati teorijom dvostrukog filma. Stvaranje (S)-mandelonitrila u Lewisovoj stanici slijedi reakcijski model u vodenoj fazi, što znači da se enzimska reakcija provodi uglavnom u vodenoj fazi i u tankom filmu u blizini međufaze odnosno izravno na međufazi. Koristeći Hattin broj moglo se pokazati da je prijenos mase benzaldehida iz organske u vodenu fazu pojačan biokatalitičkom reakcijom (S)-hidroksinitril liaze iz Hevea brasiliensis

    Comparison of Three Extraction Methods for 17β-Estradiol in Sand, Bentonite, and Organic-Rich Silt Loam

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    Extraction is an important procedure for samples that contain soil because other compounds in soil may affect analysis of estrogens. This study was conducted to evaluate three different extraction methods for 17β-estradiol in soil. Sand, bentonite, and organicrich silt loam were spiked with 1 mg kg −1 of 17β-estradiol as a model compound of estrogens. 17β-estradiol and its metabolites, estrone and estriol, were extracted using (i) a modified Bligh and Dyer extraction, (ii) a pressurized fluid extraction, and (iii) a diethyl ether extraction, and measured by liquid chromatography tandem mass spectrometry. There were significant differences in the extraction efficiency for 17β-estradiol among the extraction methods and the soils: the efficiencies ranged from 10% to 97%. Overall, the diethyl ether extraction method had the largest efficiency of 17β-estradiol with 45% and 57% for bentonite and silt loam, respectively. Transformation of 17β-estradiol to estrone and estriol in the different extraction methods was less than 3.6% during the extraction procedures. This study underlined the importance of sample preparation for estrogen analysis in soil samples

    The role of an efficient characterization of plant extracts for breeding and the transition from wild collection to controlled cultivation

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    Die Inkulturnahme noch nicht fest etablierter Heil- und Gewürzpflanzen steht vor folgendem Dilemma: Einerseits ist eine steigende Nachfrage nach Ware aus kontrolliertem, dokumentiertem, überprüfbarem, heimischem Anbau zu verzeichnen und eine Erhöhung der Anbauflächen dieser Arten politisch gewünscht. Andererseits wird die Anbauware im Preis, je nach Versorgungslage, mit dem Preis der Ware aus Wildsammlungen verglichen. Bei vergleichbaren Qualitäten erhält dann in der Regel die preiswertere Wildsammelware den Vorzug im Einkauf. Dies führt dazu, dass eine kontinuierliche Versorgung der Verarbeitungsbetriebe mit Ware aus kontrolliertem Anbau immer wieder zusammenbricht, da die Anbauer sich nicht auf Preise und Abnahme verlassen können. Auswege aus diesem Dilemma bestehen darin, entweder mit dem Anbau zu warten, bis die Wildsammlungen versagen oder das anzubauende Material qualitativ deutlich von der Wildsammelware abzugrenzen. An den Beispielen Echte Arnika (Arnica montana L.) und Russischer Löwenzahn (Taraxacum kok-saghyz L.E.Rodin) wird gezeigt, dass - vom Wildmaterial ausgehend - in den ersten Selektionszyklen enorm große Zuchtfortschritte erzielt werden können; vorausgesetzt die Ziele sind klar definiert und es steht eine ausreichende Analytik-Kapazität zur Verfügung. Eine solche kann beispielweise mittels moderner Kernspinresonanzspektroskopie (NMR) mit entsprechender software-basierter Datenanalyse realisiert werden und wird im Folgenden, im oben genannten Kontext, diskutiert.The cultivation of not yet well-established medicinal and herbal plants faces the following dilemma: On the one hand there is an increasing demand for goods from controlled, documented, verifiable, domestic cultivation and an increase in the acreage of these species is politically desired. On the other hand, the cultivated product is compared in price, depending on the supply situation, with the price of the product from wild collections. Usually, this results in the use of the cheaper wild collected goods. As a result, the continuous supply of raw material from controlled cultivation to the processing plants collapses time and again as growers can not rely on prices and acceptance. The solution to this dilemma is either to wait with the cultivation until the wild collections fail or the quality of the material to be grown is clearly differentiated from the wild collection. Based on two examples, Arnica (Arnica montana L.) and Russian Dandelion (Taraxacum kok-saghyz L.E.Rodin), is demonstated that - starting from the wild material - high breeding progress can be achieved in the first selection cycles. A necessary precondition is, that the goals are clearly defined and that there is sufficient capacity available to analyze output traits and lead ingredients. Such can be realized for example by means of modern nuclear magnetic resonance (NMR) analysis techniques with appropriate software-based data analysis and will be discussed below

    Arznei- und Gewürzpflanzenanalytik im Hochdurchsatz – Technologie, Möglichkeiten und Anwendungen der numares NMR-Plattform

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    Um eine effiziente Analytik von Arznei- und Gewürzpflanzen zu gewährleisten und die hohe Variabilität an auftretenden Matrizes und Probentypen, ebenso wie die unterschiedlichsten analytischen Fragestellungen und Anforderungen bearbeiten zu können, ist eine Vielzahl komplementärer analytischer Methoden erforderlich.Die numares AG nutzt einen neuen, innovativen Ansatz, basierend auf der Kernspinresonanzspektroskopie (NMR), um Pflanzenzüchter und die verarbeitende Industrie bei der Analyse und Optimierung von Züchtungsprojekten, Prozessabläufen oder in der Qualitätskontrolle zu unterstützen. Nachfolgend werden anhand ausgewählter Beispiele die Technologie und deren Möglichkeiten und Anwendungsgebiete vorgestellt. Stichwörter: NMR, Hochdurchsatzanalytik, Elitenselektion, Metobolomic ProfilingMedicinal and Aromatic Plant Analysis in high-throughput – technology, possibilities and applications of the numares NMR-platformTo ensure an efficient analysis of medicinal and aromatic plants and to be able to handle the high variability occurring in matrices and sample types a variety of complementary analytical methods is required. The numares AG provides a new and innovative approach based on nuclear magnetic resonance (NMR) spectroscopy to assist plant breeders and industry in the analysis and optimization of breeding projects, process flows and in quality control. The technology, its potential and applications are presented below based on selected examples. Keywords: NMR, high-throughput screening, elite selection, metobolomic profilin
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