Fabrication and application of structured graphene/polymer based composites

Despite there being a significant development in polymer composites for multiple applications over the past few decades, there are still many difficulties relating to the effective distribution of nanoparticles such as Graphene and other 2D materials in preparing structure and minimising aggregation. To overcome these obstacles a simple method for modulating the properties of the composites by controlling the organization of the fillers, using an ordered lattice of polymer particles as a template, is described. This technique can facilitate the self-assembly of nanomaterials while preserving their useful properties and allows well-defined interface between the polymer and the nanomaterial resulting in a honeycomb-like arrangement. The ideal case would be to obtain a segregated percolating network whereby low loadings of nanoparticles are added to obtain high performance systems and thus reduce the cost for possible industrial applications. The enhancement of the mechanical and electrical properties of the composites suggests the use of these materials for different applications such as transport applications, where the combination of high strength and lightweight is required. Moreover, to reinforce systems that are very delicate such as membranes or fibres or for possible applications in sensor technology, molecular electronics, supercapacitors, electrochromic devices and pressure sensitive adhesives materials. The physical properties of these composites can be tailored using different matrices such as natural rubber, or a bimodal particle system, to create materials with high density and low void fractions, and hence very low percolation threshold. Furthermore, the combination of excellent monolayer fraction and homogenous dispersion of the GO within the polymer dispersion leads to highly uniform films, with good distribution of the filler throughout, in a segregated network. A reduction in situ proceeds to improve the innate properties of the GO, but also to modify the polymer in close proximity through and exothermic process, thus providing a much improved interface between filler and matrix, improving both the electrical and mechanical properties. The advantage of this method to organize the graphene nanoparticles in a segregated pathway does not require the use of expensive equipment or materials, and it is a promising way to open up pathways to tunable electronic composite materials on a large scale

Liver infarctions as the first manifestation of antiphospholipid antibody syndrome in pregnancy: a case report

Background: The differential diagnosis of abdominal pain in pregnant women is broad. Liver diseases as the origin of abdominal pain in pregnancy are rare, and severe forms occur in less than 0.1% of pregnancies. Some disorders, such as hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome and preeclampsia, are unique to pregnancy, while others, such as antiphospholipid antibody syndrome, may manifest in pregnancy but have consequences beyond the current pregnancy. All of them require prompt identification and treatment. Case presentation: A 27-year-old Caucasian woman who was 15+1 weeks pregnant reported to the emergency department twice due to stabbing right-upper-quadrant abdominal pain. Initial laboratory testing revealed mild leukocytosis and slightly elevated liver enzymes. On second presentation, the patient was febrile and had an increased C-reactive protein concentration. Over the course of the next days, nonhemolytic anemia and thrombocytopenia emerged with elevated liver enzymes. Coagulation studies also revealed a prolongation of activated partial thromboplastin time. Magnetic resonance imaging showed nonspecific alterations in the right liver lobe, possibly corresponding to infection or infarction. A hepatic viral infection was ruled out. At that time, the most likely diagnosis was cholangitis with liver abscess formation, and antibiotic therapy was started. Further worsening of the anemia and thrombocytopenia, development of proteinuria, together with a miscarriage on the fourth day of hospitalization resulted in the tentative diagnosis of (triple-positive) antiphospholipid antibody syndrome, which was confirmed 12 weeks after the initial investigation. Treatment consisted of prompt anticoagulation with heparin and later on with a vitamin K antagonist as well as high-dose glucocorticoid therapy. There was no need for intravenous immunoglobulin therapy or plasma exchange, although we suspected a catastrophic form of antiphospholipid antibody syndrome due to infarctions of the liver, placenta, and possibly kidneys (proteinuria). The outcome was favorable. Conclusion: We report a 27-year-old pregnant woman whose abdominal pain was caused by liver infarctions as the first manifestation of catastrophic antiphospholipid antibody syndrome. The antiphospholipid antibody syndrome was possibly secondary to hitherto clinically silent systemic lupus erythematosus since the antinuclear antibodies were increased later on. Hydroxychloroquine therapy was initiated to prevent antiphospholipid antibody syndrome recurrence in a future pregnancy. Keywords: Abortion; Antiphospholipid antibody syndrome; Case report; Hepatopathy; Liver lesions; Pregnancy; Systemic lupus erythematosu

G-protein coupled receptor 88 knock-down in the associative striatum reduces the psychiatric symptoms in a translational model of Parkinson's disease

Running title: Gpr88 gene therapy for PD psychiatric symptoms

Vitamin E–loaded dialyzer resets PBMC-operated cytokine network in dialysis patients

Vitamin E–loaded dialyzer resets PBMC-operated cytokine network in dialysis patients.BackgroundIn hemodialysis patients the activity of stimulated Th1 lymphocytes is depressed, while Th2 cells are constitutively primed. Such phenomena may depend on monocyte activation and altered release of interleukin (IL)-12 and IL-18, which regulate Th cell differentiation. Reactive oxygen species (ROS) activate monocytes; therefore, a hemodialyzer with antioxidant activity would contrast ROS, prevent monocyte activation, reset IL-12 and IL-18 release, and restore Th1/Th2 balance.MethodsTen patients on regular dialysis treatment (RDT) with cellulosic membrane (CM) were shifted to vitamin E–coated dialyzer (VE). During treatment with CM and after 3, 6, and 12months of treatment with VE, peripheral blood mononuclear cells (PBMC) and purified CD4+ cells were isolated, and cultured, resting, mitogen-stimulated, and interferon γ (IFNγ), IL-4, IL-10, IL-12, and IL-18 release was measured. Vitamin E and A plasma levels and the effects of a single dialysis session on peripheral blood NO levels were assayed.ResultsThe constitutive release of IL-4 and IL-10 by CD4+ cells was abated significantly by treatment with VE (nadir -77.8% and -55.3%, respectively, at 12months). INFγ release by mitogen-stimulated CD4+ recovered with VE (zenith +501% at 12months). PBMC constitutive production of IL-12 and IL-18 was significantly reduced by VE (nadir at 12months -64.7% and -51.3%, respectively). VE increased plasma levels of vitamins E and A. NO plasma levels fell after a single dialysis treatment with VE (-17%, P < 0.05) in contrast with CU (+27.1%, P < 0.05).ConclusionThe network of cytokines released by monocytes and Th cells is reset toward normality by treatment with vitamin E–coated dialyzer

Functional liquid structures by emulsification of graphene and other two-dimensional nanomaterials

Pickering emulsions stabilised with nanomaterials provide routes to a range of functional macroscopic assemblies. We demonstrate the formation and properties of water-in-oil emulsions prepared through liquid-phase exfoliation of graphene. Due to the functional nature of the stabiliser, the emulsions exhibit conductivity due to inter-particle tunnelling. We demonstrate a strain sensing application with a large gauge factor of ~40; the highest reported in a liquid. Our methodology can be applied to other two-dimensional layered materials opening up applications such as energy storage materials, and flexible and printable electronics

Mesoporous Titania powders: the role of precursors, ligand addition and calcination rate on their morphology, crystalline structure and photocatalytic activity

We evaluate the influence of the use of different titania precursors, calcination rate, and ligand addition on the morphology, texture and phase content of synthesized mesoporous titania samples, parameters which, in turn, can play a key role in titania photocatalytic performances. The powders, obtained through the evaporation-induced self-assembly method, are characterized by means of ex situ X-Ray Powder Diffraction (XRPD) measurements, N2 physisorption isotherms and transmission electron microscopy. The precursors are selected basing on two different approaches: the acid-base pair, using TiCl4 and Ti(OBu)4, and a more classic route with Ti(OiPr)4 and HCl. For both precursors, different specimens were prepared by resorting to different calcination rates and with and without the addition of acetylacetone, that creates coordinated species with lower hydrolysis rates, and with different calcination rates. Each sample was employed as photoanode and tested in the water splitting reaction by recording I-V curves and comparing the results with commercial P25 powders. The complex data framework suggests that a narrow pore size distribution, due to the use of acetylacetone, plays a major role in the photoactivity, leading to a current density value higher than that of P25

Hyaluronic acid-decorated liposomes as innovative targeted delivery system for lung fibrotic cells

Collagen Tissue Disease-associated Interstitial Lung Fibrosis (CTD-ILDs) and Bronchiolitis Obliterans Syndrome (BOS) represent severe lung fibrogenic disorders, characterized by fibro-proliferation with uncontrolled extracellular matrix deposition. Hyaluronic acid (HA) plays a key role in fibrosis with its specific receptor, CD44, overexpressed by CTD-ILD and BOS cells. The aim is to use HA-liposomes to develop an inhalatory treatment for these diseases. Liposomes with HA of two molecular weights were prepared and characterized. Targeting efficiency was assessed toward CTD-ILD and BOS cells by flow cytometry and confocal microscopy and immune modulation by RT-PCR and ELISA techniques. HA-liposomes were internalized by CTD-ILD and BOS cells expressing CD44, and this effect increased with higher HA MW. In THP-1 cells, HA-liposomes decreased pro-inflammatory cytokines IL-1\u3b2, IL-12, and anti-fibrotic VEGF transcripts but increased TGF-\u3b2 mRNA. However, upon analyzing TGF-\u3b2 release from healthy donors-derived monocytes, we found liposomes did not alter the release of active pro-fibrotic cytokine. All liposomes induced mild activation of neutrophils regardless of the presence of HA. HA liposomes could be also applied for lung fibrotic diseases, being endowed with low pro-inflammatory activity, and results confirmed that higher MW HA are associated to an increased targeting efficiency for CD44 expressing LFs-derived from BOS and CTD-ILD patients

Controlled assembly and reduction of graphene oxide networks for conductive composites

Work presented at the 2019 ACS Spring National Meeting, March 28-April 4, 2019 · Orlando, FL.Graphene has attracted enormous interest in the scientific community as the first 2D material with exceptional mechanical, electronic and thermal properties. Pristine Graphene is notoriously difficult to process for macroscale applications, to overcome this many people use graphene oxide (GO) instead. GO is water soluble and easily functionalised and so can be simply processed into various systems. GO lacks the exceptional electronic properties of graphene due to structural disorder, therefore an important area of research is on the reduction of GO, which partly restores the structure and properties of graphene. Various techniques have been developed to perform the reduction step. We report a simple approach for preparing conductive Polymer Latex-rGO composites by using a latex-assembly method. After a treatment in the oven at low T, we can reduce the GO in situ. We make use of the inherent GO properties to optimise the aqueous composite fabrication, which is scalable and adaptable, and then restore conductivity with a simple, low temperature, heating step; opening up pathways to tunable electronic composite materials on a large scale.Peer reviewe

Explosive percolation yields highly-conductive polymer nanocomposites

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Nanocomposites present a structurally- and chemically-varied playground to realise explosive percolation in practically-applicable systems but this is yet to be exploited by design. Herein, we demonstrate composites of graphene oxide and synthetic polymer latex which form segregated networks, leading to low percolation threshold and localisation of conductive pathways. In situ reduction of the graphene oxide at temperatures of <150 °C drives chemical modification of the polymer matrix to produce species with phenolic groups, which are known crosslinking agents. This leads to conductivities exceeding those of dense-packed networks of reduced graphene oxide, illustrating the potential of explosive percolation by design to realise low-loading composites with dramatically-enhanced electrical transport properties