Numerical modeling of microplastic interaction with fine sediment under estuarine conditions

Microplastic (MP) pollution is an important challenge for human life which has consequently affected the natural system of other organisms. Mismanagement and also careless handling of plastics in daily life has led to an accelerating contamination of air, water and soil compartments with MP. Under estuarine conditions, interactions with suspended particulate matter (SPM) like fine sediment in the water column play an important role on the fate of MP. Further studies to better understand the corresponding transport and accumulation mechanisms are required. This paper aims at providing a new modeling approach improving the MP settling velocity formulation based on higher suspended fine sediment concentrations, as i.e. existent in estuarine turbidity zones (ETZ). The capability of the suggested approach is examined through the modeling of released MP transport in water and their interactions with fine sediment (cohesive sediment/fluid mud). The model results suggest higher concentrations of MP in ETZ, both in the water column as well as the bed sediment, which is also supported by measurements. The key process in the modeling approach is the integration of small MP particles into estuarine fine sediment aggregates. This is realized by means of a threshold sediment concentration, above which the effective MP settling velocity increasingly approaches that of the sediment aggregates. The model results are in good agreement with measured MP mass concentrations. Moreover, the model results also show that lighter small MP particles can easier escape the ETZ towards the open sea

Production and characterisation of environmentally relevant microplastic test materials derived from agricultural plastics

Soil environments across the globe, particularly in agricultural settings, have now been shown to be contaminated with microplastics. Agricultural plastics – such as mulching films – are used in close or direct contact with soils and there is growing evidence demonstrating that they represent a potential source of microplastics. There is a demand to undertake fate and effects studies to understand the behaviour and potential long-term ecological risks of this contamination. Yet, there is a lack of test materials available for this purpose. This study describes the manufacture and characterisation of five large (1–40 kg) batches of microplastic test materials derived from agricultural mulching films. Batches were produced from either polyethylene-based conventional mulching films or starch-polybutadiene adipate terephthalate blend mulching films that are certified biodegradable in soil. Challenges encountered and overcome during the micronisation process provide valuable insights into the future of microplastic test material generation from these material types. This includes difficulties in micronising virgin polyethylene film materials. All five batches were subjected to a thorough physical and chemical characterisation - both of the original virgin films and the subsequent microplastic particles generated - including a screening for the presence of chemical additives. This is a critical step to provide essential information for interpreting particle fate or effects in scientific testing. Trade-offs between obtaining preferred particle typologies and time and cost constraints are elucidated. Several recommendations emerging from the experiences gained in this study are put forward to advance the research field towards greater harmonisation and utilisation of environmentally relevant test materials

High-affinity RNA binding by a hyperthermophilic single-stranded DNA-binding protein

Single-stranded DNA-binding proteins (SSBs), including replication protein A (RPA) in eukaryotes, play a central role in DNA replication, recombination, and repair. SSBs utilise an oligonucleotide/oligosaccharide-binding (OB) fold domain to bind DNA, and typically oligomerise in solution to bring multiple OB fold domains together in the functional SSB. SSBs from hyperthermophilic crenarchaea, such as Sulfolobus solfataricus, have an unusual structure with a single OB fold coupled to a flexible C-terminal tail. The OB fold resembles those in RPA, whilst the tail is reminiscent of bacterial SSBs and mediates interaction with other proteins. One paradigm in the field is that SSBs bind specifically to ssDNA and much less strongly to RNA, ensuring that their functions are restricted to DNA metabolism. Here, we use a combination of biochemical and biophysical approaches to demonstrate that the binding properties of S. solfataricus SSB are essentially identical for ssDNA and ssRNA. These features may represent an adaptation to a hyperthermophilic lifestyle, where DNA and RNA damage is a more frequent event.Publisher PDFPeer reviewe

Context-Awareness in MobiLife

approaching Context-Awareness from the perspective of mobile applications and their enabling components. It envisions a highly distributed and loosely coupled solution in order to exchange context information on different semantic context levels between applications, enabling components and raw context sources. Semantic meaning of the context information exchanged is added via distributed ontology’s attached to it. The definition of the mechanism and interfaces is described by the MobiLife Context Management Framework. Actual context data used within MobiLife applications is provided and defined by a number of specific context providers. New context providers can be easily introduced based on the generic definition of them. The paper aims to provide the overview to the MobiLife context-awareness approach and describes its usage by the means of two MobiLife applications

Multimodal Adaptation And Enriched Interaction Of Multimedia Content For Mobile Users

This paper introduces an architecture, together with an implemented scenario, capable of dynamically adapt the way mobile users consume and interact with multimedia content. The architecture is based on a representative scenario identified by the European project SPICE, in which multimedia content is distributed to a user independently of his/her contextual situation. The implemented scenario includes the following scenes: content selection using a personal mobile phone, content distribution to the most suitable device according to the user's context, and presentation continuity when the user moves to another location. This paper reports on the defined architecture and the current status of its implementation. It shows the initial results in the form of screenshots

Managing Personal Communication Environments in Next Generation Service Platforms

The current access to mobile services a user has, is defined by the user's mobile terminal as the single entry point to an operators network. This comes along with a set of limitations. Although performance and multimedia capabilities of mobile devices are constantly increasing, user-service interaction is still limited due to physical constraints imposed by the form factor. Another drawback is the varying ability of devices to download and execute new services. At the same time it is not possible to synchronise, exchange or share the user's data and media content among different devices. In order to overcome these limitations this paper presents the concept of the Distributed Communication Sphere and the according architectural framework that allows its management. This framework defines functional components to enable multi-device delivery of communication and media service sessions, user input interpretation, terminal management and resource discovery. It also provides flexible service delivery through the dynamic desktop component and relies on intelligent service enablers of the underlying service platform architecture, such as context-awareness, service provisioning and personal profile enablers. The work has been performed as part of the EU IST-SPICE (027617) project targeting intelligent extensions for next generation service platforms