Search results for "Spectroscopy"
showing 10 items of 10293 documents
Developing Antibiofilm Fibrillar Scaffold with Intrinsic Capacity to Produce Silver Nanoparticles
2022
The development of biomedical systems with antimicrobial and antibiofilm properties is a difficult medical task for preventing bacterial adhesion and growth on implanted devices. In this work, a fibrillar scaffold was produced by electrospinning a polymeric organic dispersion of polylactic acid (PLA) and poly(α,β-(N-(3,4-dihydroxyphenethyl)-L-aspartamide-co-α,β-N-(2-hydroxyethyl)-L-aspartamide) (PDAEA). The pendant catechol groups of PDAEA were used to reduce silver ions in situ and produce silver nanoparticles onto the surface of the electrospun fibers through a simple and reproducible procedure. The morphological and physicochemical characterization of the obtained s…
New Bioactive Peptides from the Mediterranean Seagrass Posidonia oceanica (L.) Delile and Their Impact on Antimicrobial Activity and Apoptosis of Hum…
2023
The demand for new molecules to counter bacterial resistance to antibiotics and tumor cell resistance is increasingly pressing. The Mediterranean seagrass Posidonia oceanica is considered a promising source of new bioactive molecules. Polypeptide-enriched fractions of rhizomes and green leaves of the seagrass were tested against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Escherichia coli), as well as towards the yeast Candida albicans. The aforementioned extracts showed indicative MIC values, ranging from 1.61 μg/mL to 7.5 μg/mL, against the selected pathogens. Peptide fractions were further analyzed thr…
BDNF as a Mediator of Antidepressant Response: Recent Advances and Lifestyle Interactions
2022
Conventional antidepressants are widely employed in several psychiatric and neurologic disorders, yet the mechanisms underlying their delayed and partial therapeutic effects are only gradually being understood. This narrative review provides an up-to-date overview of the interplay between antidepressant treatment and Brain-Derived Neurotrophic Factor (BDNF) signaling. In addition, the impact of nutritional, environmental and physiological factors on BDNF and the antidepressant response is outlined. This review underlines the necessity to include information on lifestyle choices in testing and developing antidepressant treatments in the future.
Polarisation dependent Raman study of single-crystal nickel oxide
2011
Abstract The magnetic domain structure and Raman scattering have been studied in NiO single-crystals with three different (100), (110) and (111) orientations. Twin-domain structure was observed in NiO(100) and NiO(110) single-crystals using cross-polarized optical microscopy. We found that the ratio of the two-magnon (at 1500 cm−1) to the two-phonon (2LO, at 1100 cm−1) Raman bands intensity is sensitive in a particular way to the type of the twin-domain pattern.
Oxidation Processes in Sicilian Olive Oils Investigated by a Combination of Optical and EPR Spectroscopy
2012
: Extra virgin olive oil (EVOO) is recognized as one of the healthiest foods for its high content of antioxidants, which forestall and slow down radical formation. Free radical-initiated oxidation is considered one of the main causes of rancidity in fats and oils. As a consequence, reliable protocols for the investigation of oil oxidation based on selective, noninvasive, and fast methods are highly desirable. Here we report an experimental approach based on UV-Vis absorbance, steady-state fluorescence, and electron paramagnetic resonance (EPR) spectroscopy for studying oxidation processes induced by temperature for a period up to 35 d on Sicilian EVOO samples. We followed the decrease in β…
Dipeptides of S-Substituted Dehydrocysteine as Artzyme Building Blocks: Synthesis, Complexing Abilities and Antiproliferative Properties †
2021
Background: Dehydropeptides are analogs of peptides containing at least one conjugate double bond between α,β-carbon atoms. Its presence provides unique structural properties and reaction centre for chemical modification. In this study, the series of new class of dipeptides containing S-substituted dehydrocysteine with variety of heterocyclic moieties was prepared. The compounds were designed as the building blocks for the construction of artificial metalloenzymes (artzymes). Therefore, the complexing properties of representative compounds were also evaluated. Furthermore, the acknowledged biological activity of natural dehydropeptides was the reason to extend the study for antiproliferativ…
Synthesis, characterization, crystal structures and biological screening of 4-amino quinazoline sulfonamide derivatives
2019
Three quinazolin-4-ylamino derivatives containing phenylbenzenesulfonamides (7a-7c) were synthesized by reacting (E)-N'-(2-cyanophenyl)-N,N-dimethyl formamidine (6) with different 4- amino-N-(phenyl)benzenesulfonamides (4a-4c) and characterized by different techniques such as HRMS, IR, 1H NMR and 13C NMR spectroscopy. The structural properties were further examined by single crystal X-ray diffraction method. The X-ray data shows that compounds 7a and 7c contain two molecules and 7b contains one molecule in the asymmetric unit. Comparison of conformation of two distinct molecules, “A” and “B”, in the asymmetric unit of 7a and 7c were studied with the aid of reported literature. The in vitro …
ART AND TECHNIQUE: ARTISTIC REPRODUCTION OF THE ANCIENT BRONZE IL GUERRIERO DA PETRALIA SOTTANA
2016
The reproduction of artistic objects is useful for museological, teaching, and commercial purposes. In some cases, the reproduction is carried out to replace the originals located in outdoor environments and to prevent the deterioration due to weathering or pollution. This article describes the different phases that led to the reproduction of the Il Guerriero da Petralia Sottana. The observation of stylistic characteristics and the physical-chemical investigation were carried out in order to obtain information about the composition of the alloy and the technological properties of the artifact by using Optical Microscopy and X- ray Fluorescence. The reproduction in wax was performed by using…
A metal-responsive interdigitated bilayer for selective quantification of mercury( ii ) traces by surface plasmon resonance
2016
Reusable surface plasmon resonance chips allowing the quantitative and selective detection of mercury(II) ions in water at the 0.01 nM level are reported. The surface-modified gold sensor consists of a rarefied self-assembled monolayer of octanethiol topped with a Langmuir–Blodgett monolayer of an amphiphilic and highly-specific chelator. The interdigitated architecture confers to the bilayer a high packing density, surface coverage, and binding-group accessibility.
Hydrophobic interactions between aroma compounds and beta-Lactoglobulin using a specific fluorescent probe and NMR
2008
International audience; Many aroma compounds are known to bind with proteins, and elucidating these bindind interactions is a key in a better knowledgment of flavour perception mechanisms (1). beta-Lactoglobulin (bLg), the major whey protein of milk, has been used as a model food protein in numerous studies. Previous work have shown different binding sites on bLg for aroma compounds as a function of their chemical class, and emphasized the importance of hydrophobic interactions (2). (...)