269 research outputs found

    Mycosporine-like Amino Acids and Other Phytochemicals Directly Detected by High-Resolution NMR on Klamath (Aphanizomenon flos-aquae) Blue-Green Algae

    Get PDF
    This study describes for the first time the use of high-resolution nuclear magnetic resonance (NMR) on Klamath (Aphanizomenon flos-aquae, AFA) blue-green algae directly on powder suspension. These algae are considered to be a "superfood", due to their complete nutritional profile that has proved to have important therapeutic effects. The main advantage of NMR spectroscopy is that it permits the detection of a number of metabolites all at once. The Klamath alga metabolome was revealed to be quite complex, and the most peculiar phytochemicals that can be detected directly on algae by NMR are mycosporine-like amino acids (porphyra-334, P334; shinorine, Shi) and low molecular weight glycosides (glyceryl \u3b2-d-galactopyranoside, GalpG; glyceryl 6-amino-6-deoxy-\u3b1-d-glucopyranoside, ADG), all compounds with a high nutraceutical value. The presence of cis-3,4-DhLys was revealed for the first time. This molecule could be involved in the anticancer properties ascribed to AFA

    Novel Bifunctional Amide-Based Initiator for the Atom Transfer Radical Polymerization of Styrene with Ascorbic Acid Acetonide as Reducing Agent

    Get PDF
    This study focuses on the synthesis and characterization of a new bifunctional benzamide initiator, CMB2HexDA, for the production of thermostable α,ω-dichloropolystyrene via ARGET ATRP. The motivation behind this research is the need to obtain functionalized polystyrene that can withstand the high temperatures used in industrial extrusion processes, as well as the previous development of a method to obtain α,ω-dialkenepolystyrene by solventless thermal dehydrohalogenation. The commonly used initiators in ATRP undergo thermal fragmentation, leading to chain length reduction and loss of telechelicity. The synthesized initiator was purified and characterized, and the resulting α,ω-dichloropolystyrenes were analyzed through GPC and NMR. The telechelic polystyrene produced with the new initiator exhibited enhanced thermal stability compared to aliphatic-halide ester initiators. Although the specific diamine used does not confer specific functionality, the developed synthetic pathway allows for the introduction of other functionalities into thermostable polystyrenes. Furthermore, the benzamidic function could be exploited to achieve controlled chemical degradation of polystyrene, resulting in more readly degradable oligomeric fragments

    \u3a0\u2011Stacking Signature in NMR Solution Spectra of Thiophene-Based Conjugated Polymers

    Get PDF
    Studies on conjugated polymers seldom report on their NMR characterization in solution. This paper shows how NMR experiments, both 1H NMR and routine 2D NMR spectra, can help in gaining a further insight into the aggregation behavior of conjugated polymers and could be used to flank the more employed solid-state NMR and other spectroscopy and microscopy techniques in the understanding of the aggregation processes. NMR spectroscopy allows distinguishing, within the class of poorly solvatochromic conjugated polymers, those highly prone to form \u3c0-stacked aggregates from the ones that have a low tendency toward \u3c0-stacking

    Integrated Geomatics Surveying and Data Management in the Investigation of Slope and Fluvial Dynamics

    Get PDF
    In mountain environments, slope and fluvial dynamics often interact, and their relationship can be investigated through an integrated methodological approach. Landslides are a source of supplying sediments into riverbeds and can interact or interrupt the water course. Water courses can trigger or re-activate slope movements. The complexity of investigating the interaction between the two dynamics needs a complementarity of methods and techniques, combining remote and proximal sensing, geotechnical in situ surveys, and repositories and catalogue datasets. This leads to a synergistic use of all the heterogeneous data from different fields and formats. The present paper provides a literature review on the approaches and surveying procedures adopted in the investigation of slope and fluvial dynamics and highlights the need to improve the integrated management of geospatial information complemented by quality information. In this regard, we outline a geodatabase structure capable of handling the variety of geoscientific data available at different spatial and temporal scales, with derived products that are useful in integrated monitoring tasks. Indeed, the future adoption of a shared physical structure would allow the merging and synergistic use of data provided by different surveyors as well as the effective storing and sharing of datasets from a monitoring perspective

    A Trifunctional ATRP Initiator Bearing Adaptable Bonds

    Get PDF
    Atom Transfer Radical Polymerization (ATRP) allows for the production of polymers with precise control over molecular weight, dispersity, topology, composition, and functionality. Functional groups can be introduced into the polymer through post-functionalization of chain ends, or on the alkyl residue of the initiator, or by introducing functionalized (co)monomers, greatly greatly enhancing the targetable applications. In addition, the desired functional group can also be carried by the ATRP initiator. Some researchers have explored initiators with hydrolysis- or heat-sensitive functionalities to impart self-healing properties to the final polymer. However, the commonly used aliphatic halide ester initiators have shown poor thermal stability. To address this issue, we recently developed a novel bifunctional benzamide-containing initiator employed in ARGET ATRP of styrene, demonstrating enhanced thermal stability. Covalent Adaptable Networks (CANs) have emerged as a solution for improving the recyclability of thermoset materials. CANs can reorganize connectivity between chains upon thermal treatment, enabling reprocessing. Our goal is to modify the structure of the benzamide-containing initiator to develop a trifunctional initiator bearing adaptable bonds

    AAV-mediated transcription factor EB (TFEB) gene delivery ameliorates muscle pathology and function in the murine model of Pompe Disease

    Get PDF
    Pompe disease (PD) is a metabolic myopathy due to acid alpha-glucosidase deficiency and characterized by extensive glycogen storage and impaired autophagy. We previously showed that modulation of autophagy and lysosomal exocytosis by overexpression of the transcription factor EB (TFEB) gene was effective in improving muscle pathology in PD mice injected intramuscularly with an AAV-TFEB vector. Here we have evaluated the effects of TFEB systemic delivery on muscle pathology and on functional performance, a primary measure of efficacy in a disorder like PD. We treated 1-month-old PD mice with an AAV2.9-MCK-TFEB vector. An animal cohort was analyzed at 3 months for muscle and heart pathology. A second cohort was followed at different timepoints for functional analysis. In muscles from TFEB-treated mice we observed reduced PAS staining and improved ultrastructure, with reduced number and increased translucency of lysosomes, while total glycogen content remained unchanged. We also observed statistically significant improvements in rotarod performance in treated animals compared to AAV2.9-MCK-eGFP-treated mice at 5 and 8 months. Cardiac echography showed significant reduction in left-ventricular diameters. These results show that TFEB overexpression and modulation of autophagy result in improvements of muscle pathology and of functional performance in the PD murine model, with delayed disease progression

    Potent Anti-Cancer Properties of Phthalimide-Based Curcumin Derivatives on Prostate Tumor Cells

    Get PDF
    Metastatic castration-resistant prostate cancer is commonly treated with chemotherapy, whose effect is less than satisfactory. This raised the need for novel agents for the treatment of prostate cancer. In the present study, five phthalimide-based curcumin derivatives were synthesized and completely characterized to assess improved stability, pharmacodynamics, and radical scavenging ability. To investigate the potential application in anti-cancer therapy, the anti-proliferative activity of the synthesized molecules was determined on aggressive prostate tumor cells. We demonstrated that the K3F21 derivative has increased potency compared to curcumin, in terms of GI50, anti-proliferative and anti-migrating activities. K3F21 inhibits anchorage-dependent and -independent growth of prostate cancer cells by altering the expression of key genes controlling cell proliferation, such as Cylins D1, B1 and B2, and apoptosis, among which Puma, Noxa, and Bcl-2 family members. Finally, the anti-cancer activity of K3F21 was demonstrated by the analysis of cancer-associated PI3K/AKT, ERK, and p38 signaling pathways

    HR-MAS NMR spectroscopy in the characterization of human tissues: Application to healthy gastric mucosa

    Get PDF
    The HR-MAS is an ideal technique for the investigation of intact tissue specimens (10-50 mg) and permits the obtainment of spectra with a resolution comparable to that observed in solution in a time that does not exceed a half of an hour for a routine analysis. The potentialities of HR-MAS NMR spectroscopy in the identification of the metabolites characterizing the healthy gastric mucosa are here presented. The direct 1D H-1 NMR spectra enables only few metabolites to be confidently assigned, and the use of selected 2D experiments strongly amplify the analytical effectiveness of the technique

    Growth Dynamics of Ultrathin Films of Benzo[1,2-b:4,5-b']dithiophene Derivatives on Au(111): A Photoelectron Spectroscopy Investigation

    Get PDF
    : Ultrathin films of a stereoisomeric mixture of benzo[1,2-b:4,5-b']dithiophene derivatives were grown by thermal evaporation in vacuum on Au(111), and they were studied in situ by photoelectron spectroscopy. X-ray photons from a non-monochromatic Mg Kα conventional X-ray source and UV photons from a He I discharge lamp equipped with a linear polarizer were used. He I photoemission results were compared with density functional theory (DFT) calculations: density of states (DOS) and 3D molecular orbital density distribution. Au 4f, C 1s, O 1s, and S 2p core-level components suggest a surface rearrangement as a function of film nominal thickness, with the variation of the molecular orientation, from flat-laying at the initial deposition to tilted toward the surface normal at coverages exceeding 2 nm. Eventually, the DFT results were exploited in assigning of the valence band experimental structures. Moreover, polarization-dependent photoemission confirmed the tilted arrangement of the molecules, starting at 2 nm. A variation of the work function of 1.4 eV with respect to the clean substrate was measured, together with a valence band offset of 1.3 eV between the organic layer and gold
    • …
    corecore