Film Blowing of Biodegradable Polymer Nanocomposites for Agricultural Applications

Films for agricultural applications, such as greenhouses films or mulching films are generally made of polyolefins such as linear low-density polyethylene (LLDPE) or low-density polyethylene. However, the use of biodegradable and/or compostable polymers is increasing, which enjoy the additional advantage that they can be left on the site since a fine life would be gradually assimilated to the underlying soil. Nevertheless, biodegradable polymeric films often do not have suitable mechanical performances. In this work, biodegradable polymer-based nanocomposite films are prepared by film blowing and compared with traditional LLDPE based nanocomposites. In particular, a biodegradable polymer blend and two different inorganic nanofillers (an organo-modified clay and a calcium carbonate with a hydrophobic coating) are used for the preparation of the nanocomposites. A detailed investigation of obtained materials is performed through rheological, mechanical, and optical characterizations. Adding nanofillers led to an increase of rigidity and tear strength of blown films without negatively affecting their ductility.     

Insights into the Action Mechanism of the Antimicrobial Peptide Lasioglossin III

Lasioglossin III (LL-III) is a cationic antimicrobial peptide derived from the venom of the eusocial bee Lasioglossum laticeps. LL-III is extremely toxic to both Gram-positive and Gram-negative bacteria, and it exhibits antifungal as well as antitumor activity. Moreover, it shows low hemolytic activity, and it has almost no toxic effects on eukaryotic cells. However, the molecular basis of the LL-III mechanism of action is still unclear. In this study, we characterized by means of calorimetric (DSC) and spectroscopic (CD, fluorescence) techniques its interaction with liposomes composed of a mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-rac-phosphoglycerol (POPG) lipids as a model of the negatively charged membrane of pathogens. For comparison, the interaction of LL-III with the uncharged POPC liposomes was also studied. Our data showed that LL-III preferentially interacted with anionic lipids in the POPC/POPG liposomes and induces the formation of lipid domains. Furthermore, the leakage experiments showed that the peptide could permeabilize the membrane. Interestingly, our DSC results showed that the peptide-membrane interaction occurs in a non-disruptive manner, indicating an intracellular targeting mode of action for this peptide. Consistent with this hypothesis, our gel-retardation assay experiments showed that LL-III could interact with plasmid DNA, suggesting a possible intracellular target.     

Graphene nanoplatelets composite membranes for thermal comfort enhancement in performance textiles

The advent of 2D nanostructured materials as advanced fillers for polymer matrix composites has opened the doors to a plethora of new industrial applications requiring both electric and thermal management. Unique properties, in fact, can arise from accurate selection and processing of 2D fillers and their matrix. Here, we report an innovative family of nanocomposite membranes based on polyurethane (PU) and graphene nanoplatelets (GNPs), designed to improve thermal comfort in functional textiles. GNP particles were thoroughly characterized (through Raman, atomic force microscopy, high-resolution TEM, scanning electron microscope), and showed high crystallinity (I_D/I_G = 0.127), low thickness (D50 < 6–8 layers), and high lateral dimensions (D50 ≈ 3 μm). When GNPs were loaded (up to 10% wt/wt) into the PU matrix, their homogeneous dispersion resulted in an increase of the in-plane thermal conductivity of composite membranes up to 471%. The thermal dissipation of membranes, alone or coupled with cotton fabric, was further evaluated by means of an ad hoc system designed to simulate a human forearm. The results obtained provide a new strategy for the preparation of membranes suitable for technical textiles, with improved thermal comfort.     

Casting process and comparison of the properties of adapted load-sensitive magnesium alloys

Magnetic magnesium alloys can be utilized as a load sensitive material, in which the inverse magnetostrictive effect is used in order to measure the actual loads in structural components manufactured from such lightweight sensor alloys. To achieve a material which exhibits magnetic properties, Mg is alloyed with ferromagnetic materials like cobalt or samarium-cobalt. Alloying elements commonly used with Mg are utilized to improve the mechanical properties of these alloys, which however may have a slight negative impact on the magnetic sensitivity. In this work, two separate magnetic Mg alloys are compared, each with properties matched to the opposing requirements: (a) high load sensitivity and (b) satisfactory mechanical properties, respectively. The precipitation behavior of the ferromagnetic constituent Co in Mg together with other alloying elements is shown on the basis of SEM images. In addition, the dissolving behavior of the Co powder during the casting process of a binary Mg–Co alloy is investigated. Cyclic loading tests employing harmonic analyses of eddy current signals are utilized in order to verify the alloys’ sensory properties. The mechanical properties are investigated using tensile tests.     

In Vitro and In Vivo Pharmaco-Toxicological Characterization of 1-Cyclohexyl-x-methoxybenzene Derivatives in Mice: Comparison with Tramadol and PCP

1-cyclohexyl-x-methoxybenzene is a novel psychoactive substance (NPS), first discovered in Europe in 2012 as unknown racemic mixture of its three stereoisomers: ortho, meta and para. Each of these has structural similarities with the analgesic tramadol and the dissociative anesthetic phencyclidine. In light of these structural analogies, and based on the fact that both tramadol and phencyclidine are substances that cause toxic effects in humans, the aim of this study was to investigate the in vitro and in vivo pharmacodynamic profile of these molecules, and to compare them with those caused by tramadol and phencyclidine. In vitro studies demonstrated that tramadol, ortho, meta and para were inactive at mu, kappa and delta opioid receptors. Systemic administration of the three stereoisomers impairs sensorimotor responses, modulates spontaneous motor activity, induces modest analgesia, and alters thermoregulation and cardiorespiratory responses in the mouse in some cases, with a similar profile to that of tramadol and phencyclidine. Naloxone partially prevents only the visual sensorimotor impairments caused by three stereoisomers, without preventing other effects. The present data show that 1-cyclohexyl-x-methoxybenzene derivatives cause pharmaco-toxicological effects by activating both opioid and non-opioid mechanisms and suggest that their use could potentially lead to abuse and bodily harm.     

Proinflammatory Interleukin-33 Induces Dichotomic Effects on Cell Proliferation in Normal Gastric Epithelium and Gastric Cancer

Interleukin (IL)-33 is a member of the interleukin (IL)-1 family of cytokines linked to the development of inflammatory conditions and cancer in the gastrointestinal tract. This study is designed to investigate whether IL-33 has a direct effect on human gastric epithelial cells (GES-1), the human gastric adenocarcinoma cell line (AGS), and the gastric carcinoma cell line (NCI-N87) by assessing its role in the regulation of cell proliferation, migration, cell cycle, and apoptosis. Cell cycle regulation was also determined in ex vivo gastric cancer samples obtained during endoscopy and surgical procedures. Cell lines and tissue samples underwent stimulation with rhIL-33. Proliferation was assessed by XTT and CFSE assays, migration by wound healing assay, and apoptosis by caspase 3/7 activity assay and annexin V assay. Cell cycle was analyzed by means of propidium iodine assay, and gene expression regulation was assessed by RT-PCR profiling. We found that IL-33 has an antiproliferative and proapoptotic effect on cancer cell lines, and it can stimulate proliferation and reduce apoptosis in normal epithelial cell lines. These effects were also confirmed by the analysis of cell cycle gene expression, which showed a reduced expression of pro-proliferative genes in cancer cells, particularly in genes involved in G0/G1 and G2/M checkpoints. These results were confirmed by gene expression analysis on bioptic and surgical specimens. The aforementioned results indicate that IL-33 may be involved in cell proliferation in an environment- and cell-type-dependent manner.     

Direct and Indirect Effect of TGFβ on Treg Transendothelial Recruitment in HCC Tissue Microenvironment

The balance between anti-tumor and tumor-promoting immune cells, such as CD4+ Th1 and regulatory T cells (Tregs), respectively, is assumed to dictate the progression of hepatocellular carcinoma (HCC). The transforming growth factor beta (TGFβ) markedly shapes the HCC microenvironment, regulating the activation state of multiple leukocyte subsets and driving the differentiation of cancer associated fibroblasts (CAFs). The fibrotic (desmoplastic) reaction in HCC tissue strongly depends on CAFs activity. In this study, we attempted to assess the role of TGFβ on transendothelial migration of Th1-oriented and Treg-oriented CD4+ T cells via a direct or indirect, CAF-mediated mechanisms, respectively. We found that the blockage of TGFβ receptor I-dependent signaling in Tregs resulted in impaired transendothelial migration (TEM) of these cells. Interestingly, the secretome of TGFβ-treated CAFs inhibited the TEM of Tregs but not Th1 cells, in comparison to the secretome of untreated CAFs. In addition, we found a significant inverse correlation between alpha-SMA and FoxP3 (marker of Tregs) mRNA expression in a microarray analysis involving 78 HCCs, thus suggesting that TGFβ-activated stromal cells may counteract the trafficking of Tregs into the tumor. The apparent dual behavior of TGFβ as both pro- and anti-tumorigenic cytokines may add a further level of complexity to the mechanisms that regulate the interactions among cancerous, stromal, and immune cells within HCC, as well as other solid tumors, and contribute to better manipulation of the TGFβ signaling as a therapeutic target in HCC patients.     

Selective hydrogenation of benzene to cyclohexene using a suspended Ru catalyst in a mechanically agitated tetraphase reactor

The reactivity on unsupported Ru based catalyst in benzene selective hydrogenation to cyclohexene has been studied. The reaction has been carried out in a tetraphase slurry reactor at 423 K, at 5 MPa, in the presence of two liquid phases: benzene and an aqueous solution of ZnSO₄ 0.6 mol l⁻¹. A detailed study of the influence of the transport phenomena on the reactivity of the catalyst has been carried out. No correlation has been found between the characteristic numbers of Weeler–Weisz and of Carberry mass transport at external liquid/solid interface or into the catalyst pores for both benzene and hydrogen and the selectivity of the catalyst. The main features of the catalysts are the strong dependence between the catalysts preparation procedure and their activity and selectivity. In particular the influence of the alkaline or the earth alkaline hydroxide, employed in the precipitation of the Ru precursor, on the selectivity, has been studied. Hydrogen chemisorption measurements indicate that the amount of weakly adsorbed hydrogen depends on the nature of the base employed in the precipitation step.     

19-Azasqualene-2,3-epoxide and its N-oxide: Metabolic fate and inhibitory effect on sterol biosynthesis in Saccharomyces cerevisiae

19-Azasqualene-2,3-epoxide was more inhibitory than the corresponding N-oxide against 2,3-oxidosqualene cyclase (OSC) solubilized from Saccharomyces cerevisiae (IC₅₀ 7±2 and 25±5 μM, respectively). Both compounds showed a reversible, noncompetitive-type inhibition on solubilized OSC. Different inhibitory properties between the compounds were especially evident when measuring [¹⁴C]acetate incorporation into nonsaponifiable lipids extracted from treated cells. In cells treated with 19-azasqualene-2,3-epoxide at 30 μM, the radioactivity associated with the oxidosqualene fraction, which was negligible in the controls, rose to over 40% of the nonsaponifiable lipids, whereas it remained at a slightly appreciable level in cells treated with the N-oxide derivative under the same conditions. 19-Azasqualene-2,3-epoxide was also more effective than the N-oxide as a cell growth inhibitor (minimal concentration of compound needed to inhibit yeast growth: 45 and >100 μM, respectively). The two inhibitors underwent different metabolic fates in the yeast: while 19-azasqualene-2,3-epoxide did not undergo any transformation, its N-oxide was actively reduced to the corresponding amine in whole and in “ultrasonically stimulated” cells. The N-oxide reductases responsible for this transformation appear to be largely confined within the microsomal fractions and require NADPH for their activity. A possible relationship between the inhibitory properties of the two compounds and their metabolic fates is discussed.     

Gelatin nanoparticles produced by a simple W/O emulsion as delivery system for methotrexate

Biodegradable hydrophilic gelatin nanoparticles, containing different initial amounts of methotrexate (MTX), were prepared using a simple solvent evaporation technique based on a single water-in-oil emulsion and stabilized by the use of glutaraldehyde as cross-linking agent. The effects of several parameters on particle size, drug encapsulation efficiency and drug release were investigated. Size and shape of the nanoparticles were examined by scanning electron microscopy. The release of MTX was monitored in vitro and the mechanism of release was studied. Particles with a mean diameter of 100–200 nm were produced, which were able to release MTX following a diffusion-controlled mechanism of release. It was observed that the initial amount of MTX used for sample loading did not have any effect on the pattern of release, while it affected the amount of drug entrapped into the nanoparticles and also both the release rate and the total amount of drug released.