Search results for " modifica"

A facile way to build up branched high functional polyaminoacids with tunable physicochemical and biological properties

2016

Abstract Here, for the first time, branched polyaminoacids bearing α-amino acids as side functions, namely PAA-co-AA and PGA-co-AA, are prepared by heterophase ring opening of polysuccinimide (PSI) with l -arginine or glycine in aqueous environment and at controlled pH. The modulation of the pH of the reaction leads to high-molecular-weight copolymers with tunable functionalization and, as consequence, with tailor-made physicochemical properties. Furthermore, a branched polyaminoacid carrying a preformed bioactive peptide ( l -trileucine) and l -arginine as side pendants, named PATA-co-AA, was synthesized via a similar pathway thus leading to complex biomimetic materials potentially exploit…

Chemical Modification of Calix[4]arenes and Resorcarenes

2001

“AD HOC” MODIFIED CLAYS FOR BIOTECHNOLOGICAL APPLICATIONS

Nowadays, the scientific community has to face with cogent problems strictly linked to the improvement of quality of live. Among the different tasks to achieve the prefixed objective the focus has been put on the drug administration, i.e., attention has been paid to propose an appropriate solution to improve the performance of a drug delivery system and to eliminate both the side effect and drawbacks. With the aim to achieve the design, synthesis, and characterization of versatile systems, with peculiar characteristics, based on clays and clays modified with a biocompatible surfactant, able to adsorb and release organic substances of pharmaceutical interest the present PhD thesis has been u…

Recent Advances in Photocatalytic Functionalization of Quinoxalin‐2‐ones

2020

Quinoxalin‐2(1H)‐one is an important class of nitrogen heterocycle in medicinal and pharmaceutical industry, which became a synthetic target in organic chemistry in recent years. This review covers the recent advances in the functionalization of this particular nitrogen heterocycle through photocatalysis.

Influence of Pendant Arms Bearing Ligating Groups on the Structure of Bismuth Porphyrins: Implications for Labeling Immunoglobulins Used in Medical A…

2004

International audience; The synthesis of two picket bismuth(III) porphyrins is reported, and their crystal structures are compared. The influence of the nature of the pickets, as well as their number, is discussed in terms of stability, kinetics of metalation, structure, and distortion of the porphyrin. Unexpectedly, the resultsindicate that the coordination sphere of bismuth is not affected by different types of distortion nor is the stability of the complex. For both types of complexes, the X-ray crystallography revealed that a single arm is actually in direct interaction with the bismuth cation, thereby allowing furtherfunctionalization on the porphyrin core as the linkage with immunoglo…

Grafting and characterization of dodecylphosphonic acid on copper: Macro-tribological behavior and surface properties

2013

International audience; Thin film of n-dodecylphosphonic acid (DDPA) was prepared on a copper oxide substrate via a molecular self-assembly process. The composition, structure, organization, surface energy, morphology, and electrochemical behavior of the DDPA filmwere characterized bymeans of X-ray photoelectron spectroscopic analysis (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), contact angle measurement v(CAM), microscopic observations, and electrochemistry. The friction behavior of the DDPA film adsorbed on copper oxide substrate sliding against a Si3N4 ball was examined on a linear reciprocating tribological tester. Worn surfaces of the DDPA film…

Thermally Induced Structural Modification of Silica Nanoparticles Investigated by Raman and Infrared Absorption Spectroscopies

2010

We report an experimental investigation by Raman and infrared (IR) absorption spectroscopies on the structural modifications induced by isochronal thermal treatments on amorphous SiO2 nanoparticles (fumed silica). In particular, three different commercial types of this material, characterized by particle mean diameters of 7, 14, and 40 nm, were subjected to thermal treatments from 100 up to 1000 °C. We found that some properties of fumed silica, such as the SiOSi mean bond angle, ring size distribution, and surface adsorbed water content, are drastically different from those of common bulk silica materials and intimately related to the particles' dimension. The SiOSi mean bond angle, probed…

Heart rate control with oral ivabradine in computed tomography coronary angiography: a randomized comparison of 7.5 mg vs 5 mg regimen.

2013

Background: Heart rate (HR) reduction is essential to achieve optimal image quality and diagnostic accuracy with computed tomography coronary angiography (CTCA). Administration of oral ivabradine seems to be more effective than beta-blockade in reducing HR in patients referred for CTCA. Methods: Two-hundred-fifty-nine consecutive patients referred for CTCA were prospectively enrolled. Patients not receiving beta-blocker at baseline (group 1) and those with beta-blocker therapy (group 2) were enrolled in the study. Each group was randomized into 3 parallel arms with 1:1:1 allocation. Patients who did not receive beta-blocker at baseline: underwent CTCA without beta blocker (n=49), and receiv…

Functionalization of Graphene with Molecules and/or Nanoparticles for Advanced Applications

2019

Graphene is considered the material of the third millennium, due to its extraordinary electronic and mechanical properties, and due to the possibility to modulate its conductivity, flexibility, elasticity, transparency, and biocompatibility by bottom-up approach. The possibility to gather the proper- ties of graphene and graphene oxide with those of functional moieties or nanoparticles is herein reviewed. The synthetic approaches proposed, either covalent or noncovalent, are aimed to tune appropriately graphene’s properties for the realization of materials for advanced uses, such as bio- medical applications, sensors, catalysis, and energy devices. In particular, methods based on covalent l…

<title>Heavy-ion induced damage and reduction of dislocation mobility in LiF single crystals</title>

2006

Ion-induced reduction of dislocation mobility in LiF crystals irradiated with swift heavy (U) and light (Ni) ions of a specific energy of 11 MeV per nucleon at fluences between 106 and 1011 ions/cm2 was studied. The arm length of dislocation rosettes produced by indentation on (100) irradiated surface was measured. It has been found that in the case of heavy ions the threshold fluence (106 ions/cm2) for impeding of dislocation arms is about 3 orders of magnitude lower than that for light ions. The results indicate that ion-induced defect aggregates play the dominating role in the impeding of dislocations. Heavy ions, which produce defect aggregates in the track core, cause also a stronger e…