Tolerance of three European native species of crayfish to hypoxia.

Species that can act as indicators of ecosystem health offer a valuable tool in the management of natural resources. Crayfish have been suggested as bioindicators of water quality in Europe and at least one species (Austropotamobius pallipes) has been studied to determine its tolerance to pollution and its potential as a bioindicator. The genus Austropotamobius includes three crayfish species native to western Europe: A. pallipes, A. italicus and A. torrentium. It was hypothesised that because of their geographical and habitat distribution, the three Austropotamobius species might vary in their value as a bioindicator of water quality. Crayfish of species A. pallipes and A. italicus were subjected to three different treatments: hypoxia (treatment 3, approx 3 mg 1(-1) O-2), light hypoxia (treatment 2, approx 5.5 mg 1(-1) O-2) and normoxia (treatment 1, control, approx 8.5 mg 1(-1) O-2). A. torrentium crayfish were only subjected to treatment 1 (control) and 3. Variations in haemolymph sodium, calcium and chloride were used as a biomarker and concentrations were measured before and after treatment to evaluate hypoxia-induced stress. Significant differences in the concentrations of sodium between the control groups (treatment 1, normoxia) and the experimental groups (treatment 3, 3 mg 1(-1) O-2) were found in the species A. pallipes and A. torrentium. Groups of A. italicus did not show any significant difference between treatments in sodium concentrations but in chloride concentrations. Crayfish of all three species demonstrated a disruption in the ion exchange process in hypoxia, but all tolerated very low oxygen concentration for an extended period of time

A simplified analytical model of ultrafine particle concentration within an indoor environment

Exposure to indoor fine and ultrafine particulate matter (PM) has been recognised as a fundamental problem as most people spend over 85% of their time indoor. Experimental data derived from a field campaign conducted in a confined environment have been used to investigate the physical mechanisms governing indoor-outdoor PM exchanges in different operating conditions, e.g. natural ventilation and infiltration. An analytical model based on the mass balance of PM has been used to estimate indoor fine and ultrafine PM concentration. Indoor-outdoor concentration ratio, penetration factor and air exchange rate have been estimated and related to the differential pressure measured at the openings

Geometrical Properties of Two-Dimensional Interacting Self-Avoiding Walks at the Theta-Point

We perform a Monte Carlo simulation of two-dimensional N-step interacting self-avoiding walks at the theta point, with lengths up to N=3200. We compute the critical exponents, verifying the Coulomb-gas predictions, the theta-point temperature T_theta = 1.4986(11), and several invariant size ratios. Then, we focus on the geometrical features of the walks, computing the instantaneous shape ratios, the average asphericity, and the end-to-end distribution function. For the latter quantity, we verify in detail the theoretical predictions for its small- and large-distance behavior.Comment: 23 pages, 4 figure

Atmospheric pressure non-equilibriumplasma for the production of composite materials

In the evolving field of tissue engineering, continuous advances are required to improve scaffold design and fabrication to obtain biomimetic supports for cell adhesion, proliferation, penetration and differentiation. Both electrospun fibrous scaffolds and hydrogels are used in this field since they well reproduce the structure of the extracellular matrix (ECM) of many biological tissues. Limitations of these two types of materials can be overcome through their combination, by developing composite structures combining enhanced mechanical properties (provided by the fibrous components) and improved cell penetration (provided by the gel phase) in a superior ability to mimic natural ECM that is constituted by both a fibrous protein network and a hydrogel matrix. Here we develop new composite materials made of electrospun PLLA scaffolds and poly(amidoamine) hydrogels with different degrees of crosslinking. To promote compatibilization and good adhesion between the two materials, surface chemical reactions between hydrogels and PLLA mats are induced by inserting amino functional groups on electrospun PLLA mats by means of atmospheric pressure non-thermal plasma. Results will be presented concerning the exposure of PLLA substrates to the plasma region generated by a Dielectric Barrier Discharge at atmospheric pressure, driven by a HV Amplifier connected to a function generator operating with a microsecond rise time and operated in N2. Surface and solid-state thermo-mechanical characterizations of plasma treated substrates and of resulting composite materials at different crosslinking degrees are presented. Results of mechanical tests show a high adhesion between hydrogel and plasma treated PLLA electrospun mats, underlining the opportunity to use atmospheric non-thermal plasmas to fabricate a composite starting from two materials otherwise physically incompatible. Potential effects of nanofibrous-hydrogel were evaluated by investigating pluripotent stem cells response

Highly transparent poly(2-ethyl-2-oxazoline)-TiO2 nanocomposite coatings for the conservation of matte painted artworks

A nanocomposite coating based on TiO2 nanoparticles and poly(2-ethyl-2-oxazoline) is used as consolidant of matte painted surfaces (temperas, watercolors, modern paintings). The aim of this work is to provide advances in the conservation of these works of art, while preserving their optical appearance, in terms of colour and gloss. Fiber Optic Reflectance Spectroscopy (FORS) measurements of a painting-model (an acrylic black monochrome) treated with the nanocomposite coatings revealed that it is possible to match the optical appearance of the painted surface by tuning the amount of nanoparticles in the polymeric matrix. The requirement of retreatability of the material has been verified by removing the nanocomposite cast on the painted surface with aqueous solutions. FTIR and SEM/EDX measurements showed that almost no traces of the nanocomposite remained on the painted surface, allowing its use for the treatment of real paintings. Test were performed using a contemporary studio-model on canvas attributed to Agostino Bonalumi (1935–2013)

Enhanced Electrospinning of Active Organic Fibers by Plasma Treatment on Conjugated Polymer Solutions

Realizing active, light-emitting fibers made of conjugated polymers by the electrospinning method is generally challenging. Electrospinning of plasma-treated conjugated polymer solutions is here developed for the production of light-emitting microfibers and nanofibers. Active fibers from conjugated polymer solutions rapidly processed by a cold atmospheric argon plasma are electrospun in an effective way, and they show a smoother surface and bead-less morphology, as well as preserved optical properties in terms of absorption, emission, and photoluminescence quantum yield. In addition, the polarization of emitted light and more notably photon waveguiding along the length of individual fibers are remarkably enhanced by electrospinning plasma-treated solutions. These properties come from a synergetic combination of favorable intermolecular coupling in the solutions, increased order of macromolecules on the nanoscale, and resulting fiber morphology. Such findings make the coupling of the electrospinning method and cold atmospheric plasma processing on conjugated polymer solutions a highly promising and possibly general route to generate light-emitting and conductive micro- and nanostructures for organic photonics and electronics

The next Generation of Action Ecology: Novel Approaches towards Global Ecological Research

Advances in the acquisition and dissemination of knowledge over the last decade have dramatically reshaped the way that ecological research is conducted. The advent of large, technology-based resources such as iNaturalist, Genbank, or the Global Biodiversity Information Facility (GBIF) allow ecologists to work at spatio-temporal scales previously unimaginable. This has generated a new approach in ecological research: one that relies on large datasets and rapid synthesis for theory testing and development, and findings that provide specific recommendations to policymakers and managers. This new approach has been termed action ecology, and here we aim to expand on earlier definitions to delineate its characteristics so as to distinguish it from related subfields in applied ecology and ecological management. Our new, more nuanced definition describes action ecology as ecological research that is (1) explicitly motivated by the need for immediate insights into current, pressing problems, (2) collaborative and transdisciplinary, incorporating sociological in addition to ecological considerations throughout all steps of the research, (3) technology-mediated, innovative, and aggregative (i.e., reliant on ‘big data\u27), and (4) designed and disseminated with the intention to inform policy and management. We provide tangible examples of existing work in the domain of action ecology, and offer suggestions for its implementation and future growth, with explicit recommendations for individuals, research institutions, and ecological societies

Understanding Interorganizational Learning Based on Social Spaces and Learning Episodes

Different organizational settings have been gaining ground in the world economy, resulting in a proliferation of different forms of strategic alliances that translate into a growth in the number of organizations that have started to deal with interorganizational relationships with different actors. These circumstances reinforce Crossan, Lane, White and Djurfeldt (1995) and Crossan, Mauer and White (2011) in exploring what authors refer to as the fourth, interorganizational, level of learning. These authors, amongst others, suggest that the process of interorganizational learning (IOL) warrants investigation, as its scope of analysis needs widening and deepening. Therefore, this theoretical essay is an attempt to understand IOL as a dynamic process found in interorganizational cooperative relationships that can take place in different structured and unstructured social spaces and that can generate learning episodes. According to this view, IOL is understood as part of an organizational learning continuum and is analyzed within the framework of practical rationality in an approach that is less cognitive and more social-behavioral

A new strategy to prevent biofilm and clot formation in medical devices: the use of atmospheric non-thermal plasma assisted deposition of silver-based nanostructured coatings

In industrialized countries, health care associated infections, the fourth leading cause of dis- ease, are a major health issue. At least half of all cases of nosocomial infections are associ- ated with medical devices. Antibacterial coatings arise as an important approach to restrict the nosocomial infection rate without side effects and the development of antibiotic resis- tance. Beside nosocomial infections, clot formation affects cardiovascular medical devices and central venous catheters implants. In order to reduce and prevent such infection, we develop a plasma-assisted process for the deposition of nanostructured functional coatings on flat substrates and mini catheters. Silver nanoparticles (Ag NPs) are synthesized exploit- ing in-flight plasma-droplet reactions and are embedded in an organic coating deposited through hexamethyldisiloxane (HMDSO) plasma assisted polymerization. Coating stability upon liquid immersion and ethylene oxide (EtO) sterilization is assessed through chemical and morphological analysis carried out by means of Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In the perspective of future clinical appli- cation, an in vitro analysis of anti-biofilm effect has been done. Moreover, we employed a murine model of catheter-associated infection which further highlighted the performance of Ag nanostructured films in counteract biofilm formation. The anti-clot performances coupled by haemo- and cytocompatibility assays have also been performed

Pericellular activation of hepatocyte growth factor by the transmembrane serine proteases matriptase and hepsin, but not by the membrane-associated protease uPA

HGF (hepatocyte growth factor) is a pleiotropic cytokine homologous to the serine protease zymogen plasminogen that requires canonical proteolytic cleavage to gain functional activity. The activating proteases are key components of its regulation, but controversy surrounds their identity. Using quantitative analysis we found no evidence for activation by uPA (urokinase plasminogen activator), despite reports that this is a principal activator of pro-HGF. This was unaffected by a wide range of experimental conditions, including the use of various molecular forms of both HGF and uPA, and the presence of uPAR (uPA receptor) or heparin. In contrast the catalytic domains of the TTSPs (type-II transmembrane serine proteases) matriptase and hepsin were highly efficient activators (50% activation at 0.1 and 3.4 nM respectively), at least four orders of magnitude more efficient than uPA. PS-SCL (positional-scanning synthetic combinatorial peptide libraries) were used to identify consensus sequences for the TTSPs, which in the case of hepsin corresponded to the pro-HGF activation sequence, demonstrating a high specificity for this reaction. Both TTSPs were also found to be efficient activators at the cell surface. Activation of pro-HGF by PC3 prostate carcinoma cells was abolished by both protease inhibition and matriptase-targeting siRNA (small interfering RNA), and scattering of MDCK (Madin–Darby canine kidney) cells in the presence of pro-HGF was abolished by inhibition of matriptase. Hepsin-transfected HEK (human embryonic kidney)-293 cells also activated pro-HGF. These observations demonstrate that, in contrast with the uPA/uPAR system, the TTSPs matriptase and hepsin are direct pericellular activators of pro-HGF, and that together these proteins may form a pathway contributing to their involvement in pathological situations, including cancer