528 research outputs found
Lipolytic enzymes in the gastric fluids of Cancer pagurus are capable of hydrolyzing biodegradable plastic
The pollution of the environment by plastics is a perpetual problem that poses a great challenge to mankind. A promising strategy to counteract the increasing pollution is the innovation and development of biodegradable materials. However, biodegradable plastics reach into the marine environment in the same way as conventional plastics and can also be ingested by marine organisms. There is a wide variety of different polymers that are used in biodegradable materials, such as polylactic acid (PLA), polybutylene succinate (PBS) or polyhydroxyalkanoates (PHAs). Those compounds are known to be enzymatically degradable by several enzymes under certain conditions. Once ingested by marine organisms such as crustaceans, the highly active mixture of enzymes in their digestive tracts may break down compounds and facilitate degradation. In this study, the hydrolytic activity of gastric fluids from Cancer pagurus on different biodegradable and conventional plastics was evaluated with pH Stat titration. The enzymes capable of hydrolyzing biodegradable plastics were isolated from the gastric fluid and characterized using several analytical methods. Separated protein fractions with a high amount of lipolytic enzymes showed the highest potential on hydrolyzing biodegradable plastics
Integration of Skyline Queries into Spark SQL
Skyline queries are frequently used in data analytics and multi-criteria
decision support applications to filter relevant information from big amounts
of data. Apache Spark is a popular framework for processing big, distributed
data. The framework even provides a convenient SQL-like interface via the Spark
SQL module. However, skyline queries are not natively supported and require
tedious rewriting to fit the SQL standard or Spark's SQL-like language. The
goal of our work is to fill this gap. We thus provide a full-fledged
integration of the skyline operator into Spark SQL. This allows for a simple
and easy to use syntax to input skyline queries. Moreover, our empirical
results show that this integrated solution of skyline queries by far
outperforms a solution based on rewriting into standard SQL
Bioplastics in the Sea: Rapid In-Vitro Evaluation of Degradability and Persistence at Natural Temperatures
The progressive substitution of petroleum-based polymers, such as polyethylene, polyvinylchloride, or polyethylene terephtalate, by so-called bioplastics facilitated the development and production of many new materials. The continuously refined properties of bioplastic compounds and their blends enable various applications. With growing production and utilization of bioplastic products, these materials are increasingly discarded into the environment. Although many of these materials are labeled biodegradable, there is limited information about their degradability under environmental conditions. We tested the enzymatic degradability of five bioplastic compounds with the rapid pH-Stat titration assay at environmentally relevant seawater temperatures between 5 and 30°C and pH 8.2. These plastics, issued from the European Horizon 2020 Project ´Bioplastics Europe´, are based on polylactic acid (PLA), polybutylene succinate (PBS), and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV). Suspensions of microparticles (< 200 µm) were incubated with each of the three hydrolytic enzymes, protease, lipase, and esterase. A PLA-based compound blended with polybutylene adipate terephthalate (PBAT) showed the highest hydrolysis rate of 30 nmol·min-1 when incubated with lipase at 30°C. All other materials showed low hydrolysis rates of less than 10 nmol·min-1. Below 20°C, hydrolysis almost ceased. Plate clearing assays with the same enzymes at 37°C and pH 5 and pH 8, respectively, largely confirmed the results of the pH-Stat titration assays. Our findings indicate that there is a potential degradation of most of the materials with at least one of these hydrolytic enzymes. Nonetheless, the rate of enzymatic degradation under environmentally relevant conditions is low, which indicates only a marginal degradability of bioplastics in the marine environment
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Leightweight Urban Computation Interchange (LUCI) System
In this paper we introduce LUCI, a Leightweight Urban Calculation Interchange system, designed to bring the advantages of calculation and content co-ordination system to small planning and design groups by the means of an open source middle-ware.The middle-ware focuses on problems typical to urban planning and therefore features a geo-data repository as well as a job runtime administration, to coordinate simulation models and its multiple views.The described system architecture is accompanied by two exemplary use cases, that have been used to test and further develop our concepts and implementations
Web-based database for the management of tissue specimens in a transregional histological research facility
BACKGROUND: In the setting of a histological research core facility sample tracking and project specific archiving of tissue specimens and communication of related data is of central importance. DESCRIPTION: Over a 24-month period 10 laboratories from two transregional research centers submitted in excess of 3000 tissue samples for histological processing and evaluation to our core facility. A web based database was set up to overcome the logistical problem of managing samples with inconsistent, duplicate and missing labels and to allow for efficient sample tracking, archiving and communication with the collaborating research laboratories. The database allows the users to remotely generate unique sample identifiers and enter sample annotation prior to sample processing. Furthermore the database facilitates communication about experimental set-up results and media files such as histological images. CONCLUSION: Our newly constructed web based portal is an important tool for the management of research samples of our histological core facility and facilitates significantly interdisciplinary and transregional research. It is freely available for scientific use
Graphical smalltalk with my optimization system for urban planning tasks
Based on the description of a conceptual framework for the representation of planning problems on various scales, we introduce an evolutionary design optimization system. This system is exemplified by means of the generation of street networks with locally defined properties for centrality. We show three different scenarios for planning requirements and evaluate the resulting structures with respect to the requirements of our framework. Finally the potentials and challenges of the presented approach are discussed in detail
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