114 research outputs found

    Direct-Write Deposition of Thermogels

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    The use of biocompatible hydrogels has widely extended the potential of additive manufacturing (AM) in the biomedical field leading to the production of 3D tissue and organ analogs for in vitro and in vivo studies. In this work, the direct-write deposition of thermosensitive hydrogels is described as a facile route to obtain 3D cell-laden constructs with controlled 3D structure and stable behavior under physiological conditions

    A primer to traction force microscopy

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    Traction force microscopy (TFM) has emerged as a versatile technique for the measurement of single-cell-generated forces. TFM has gained wide use among mechanobiology laboratories, and several variants of the original methodology have been proposed. However, issues related to the experimental setup and, most importantly, data analysis of cell traction datasets may restrain the adoption of TFM by a wider community. In this review, we summarize the state of the art in TFM-related research, with a focus on the analytical methods underlying data analysis. We aim to provide the reader with a friendly compendium underlying the potential of TFM and emphasizing the methodological framework required for a thorough understanding of experimental data. We also compile a list of data analytics tools freely available to the scientific community for the furtherance of knowledge on this powerful technique

    Utilization of various lignocellulosic biomass for the production of nanocellulose: a comparative study

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    Nanocellulose was successfully extracted from five different lignocellulosic biomass sources viz. banana rachis, sisal, kapok, pineapple leaf and coir using a combination of chemical treatments such as alkaline treatment, bleaching and acid hydrolysis. The shape, size and surface properties of the nanocellulose generally depend on the source and hydrolysis conditions. A comparative study of the fundamental properties of raw material, bleached and nanocellulose was carried out by means of Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, birefringence, X-ray diffraction, inverse gas chromatography and thermogravimetric analysis. Through the characterization of the nanocellulose obtained from different sources, the isolated nanocellulose showed an average diameter in the range of 10–25 nm, high crystallinity, high thermal stability and a great potential to be used with acid coupling agents due to a predominantly basic surface. This work provides an insight into the effective utilization of a variety of plant biomass as a potential source for nanocellulose extraction.info:eu-repo/semantics/publishedVersio

    Gas Analyses of First complete JET Cryopump Regeneration with ITER-Like Wall

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    Analytical results of a complete JET cryopump regeneration, including the nitrogen panel, following the first ITER-Like Wall campaign are presented along with the in-situ analyses of residual gas. H/D mixtures and impurities such as nitrogen and neon were injected during plasma operation in the vessel to study radiation cooling in the scrape-off-layer and divertor region. The global gas inventory over the campaign is incomplete, suggesting residual volatile impurities are remaining on the cryogenic panel. This paper presents results on a) residual deuterium on the panel which is related to the campaign very low, b) impurities like nitrogen which sticks on the panel and c) the ammonia production which can be observed in the RGA spectrum.Comment: 7 pages, 3 figures. This is an author-created, un-copyedited version of an article accepted for publication in Physica Scripta. IOP Publishing Ltd and IAEA are not responsible for any errors or omissions in this version of the manuscript or any version derived from i

    Temperature-sensitive poly(vinyl alcohol)/poly(methacrylate-co-N-isopropyl acrylamide) microgels for doxorubicin delivery

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    Microgels based on poly(vinyl alcohol), PVA, grafted with methacrylate side chains, MA, incorporating N-isopropylacrylamide, NiPAAm, monomer, were prepared by water-in-water emulsion polymerization method. These systems exhibit a spherical shape and a volume-phase transition, that is, shrinking, below physiological temperature. The behavior of these microgels were studied with respect to their average size and size distribution, swelling, and release properties. It was observed that the stirring speed is a key parameter for controlling the amount of incorporated NiPAAm, the particle size and the sharpness of the volume-phase transition. The volume-phase transition temperature, VPPT, of the microgels was evaluated around 38 and 34 T for microgels with a NiPAAm/methacrylate molar ratio of 0.8 and 2.4, respectively. Water uptake increased with the amount of NiPAAm monomer present in the polymer network. In vitro biocompatibility of microgels was assessed with respect to NIH3T3 mouse fibroblasts. O-Succinoylated microgels were loaded with doxorubicin by exploiting the favorable electrostatic interaction between negatively charged microgel surface and positively charged doxorubicin. The drug release was influenced by the microgels surface/volume ratio. At physiological temperatures, above the VPTT exhibited by these systems, the release was enhanced by the specific area increase. This study provides the background for the design of an injectable device suitable for the controlled delivery of doxorubicin based on the volume-phase transition of microgels

    The endocannabinoid system in gp120-mediated insults and HIV-associated dementia

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    Endocannabinoids (eCBs) include a group of lipid mediators that act as endogenous agonists at cannabinoid (CB(1), CB(2)) and vanilloid (TRPV1) receptors. In the last two decades a number of eCBs-metabolizing enzymes have been discovered that, together with eCBs and congeners, target receptors and proteins responsible for their transport and intracellular trafficking form the so-called "endocannabinoid system" (ECS). Within the central nervous system ECS elements participate in neuroprotection against neuroinflammatory/neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis. More recently, a role for eCBs has been documented also in human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120-mediated insults, and in HIV-associated dementia (HAD). The modulation of ECS in the latter disease conditions is the subject of this review, that will also address the molecular mechanisms underlying the neuroprotective effects of eCBs. In particular, the interactions between neurons and glia during neuroinflammation, and the alterations of ECS in these cells upon gp120 insults and HAD will be discussed, along with the potential therapeutic exploitation of ECS-oriented drugs for the treatment of HAD and related disorders

    Structure and photosynthetic properties of phytoplankton assemblages in a highly dynamic system, the Northern Adriatic Sea

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    The photosynthetic properties of phytoplankton populations as related to physicalechemical variations on small temporal and spatial scales and to phytoplankton size structure and pigment spectra were investigated in the Northern Adriatic Sea off the Po River delta in late winter 1997. Large diatoms (fucoxanthin) dominated the phytoplankton in the coastal area whereas small phytoflagellates (mainly 19-hexanoyloxyfucoxanthin, chlorophyll b, 19-butanoyloxyfucoxanthin) occurred outside the front. The front was defined by the steep gradient in density in the surface layer separating low-salinity coastal waters from the offshore waters. Physical features of the area strongly influenced phytoplankton biomass distributions, composition and size structure. After high volumes of Po River discharge several gyres and meanders occurred in the area off the river delta in February. Decreasing river discharge and the subsequent disappearance of the gyres and the spreading dilution of the river plume was observed in March. The dynamic circulation of February resulted in high photosynthetic capacity of the abundant phytoplankton population (>3.40 mg m-3). In March, the slow circulation and an upper lowsalinity water layer, segregated from the deeper layers, resulted in lack of renewal of this water mass. The huge phytoplankton biomass, up to 15.77 mg chl a m-3, became nutrient depleted and showed low photosynthetic capacity. In February, an exceptionally high PmaxB, 20.11 mg C (mg chl a)-1 h-1 was recorded in the Po River plume area and average PmaxB was three-fold in February as compared to the March recordings, 10.50 mg C (mg chl a)-1 h-1 and 3.22 mg C (mg chl a)-1 h-1, respectively. The extreme variability and values of phytoplankton biomass in the innermost plume area was not always reflected in primary production. Modeling of circulation patterns and water mass resilience in the area will help to predict phytoplankton response and biomass distributions. In the frontal area, despite a considerable variability in environmental conditions, our findings have shown that the phytoplankton assemblages will compensate for nutrient depression and hydrographic constraints, by means of size and taxonomic composition and, as a result, the variability in the photosynthetic capacity was much less pronounced than that observed for other parameters
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