Search results for " modifica"
showing 10 items of 817 documents
Novel cationic polyaspartamide with covalently linked carboxypropyl-trimethyl ammonium chloride as a candidate vector for gene delivery
2006
Abstract The non-viral gene vector properties of a protein-like polymer, the α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) were investigated after its derivatization with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) as molecule bearing cationic groups, in order to obtain stable polycations able to condense DNA. PHEA was firstly functionalized with hydrazide pendant groups by reaction with hydrazine monohydrate (HYD), obtaining the polyhydrazide α,β-poly(N-2-hydroxyethyl/carbazate)- d , l -aspartamide (PHEA–HYD). In this paper we reported that polymer functionalization degree can be easily modulated by varying reaction conditions, so allowing us to produce two PHEA derivatives…
Rapid Surface Functionalization of Hydrogen-Terminated Silicon by Alkyl Silanols
2017
Surface functionalization of inorganic semiconductor substrates, particularly silicon, has focused attention toward many technologically important applications, involving photovoltaic energy, biosensing and catalysis. For such modification processes, oxide-free (H-terminated) silicon surfaces are highly required, and different chemical approaches have been described in the past decades. However, their reactivity is often poor, requiring long reaction times (2-18 h) or the use of UV light (10-30 min). Here, we report a simple and rapid surface functionalization for H-terminated Si(111) surfaces using alkyl silanols. This catalyst-free surface reaction is fast (15 min at room temperature) and…
Novel Multifunctional Polymeric Photoinitiators and Photo-Coinitiators Derived from Hyperbranched Polyglycerol
2007
A new class of hyperbranched PPIs and PPCs have been prepared. The introduction of compatibilizing groups such as MEEA or trimethylacetate enhanced their solubility in radiation-curable formulations and led to an improved photoactivity compared with the corresponding MPI and MPC. Although the molecular weights of the subject PPIs and PPCs exceeded 800 g mol -1 , the viscosities of the radiation-curable formulations were still suitable for inkjet application. The combination of high photoactivity, low viscosity, and low extract-ability after curing rendered the resulting hyperbranched PPIs and PPCs attractive as components in the inkjet ink for inkjet printing, e.g., in food packaging.
Site-specific halloysite functionalization by polydopamine: A new synthetic route for potential near infrared-activated delivery system
2022
Abstract Halloysite nanotubes (HNTs) represent a versatile core structure for the design of functional nanosystems of biomedical interest. However, the development of selective methodologies for the site-controlled functionalization of the nanotubes at specific sites is not an easy task. This study aims to accomplish a procedure for the site-selective/specific, “pin-point”, functionalization of HNTs with polydopamine (HNTs@PDA). This goal was achieved, at pH 6.5, by exploiting the basicity of ZnO nanoparticles anchored on the HNTs external surface (HNTs@ZnO) to induce a punctual polydopamine polymerization and coating. The morphology and the chemical composition of the nanomaterial was demo…
Influence of DNA Repair on Nonlinear Dose-Responses for Mutation
2013
Recent evidence has challenged the default assumption that all DNA-reactive alkylating agents exhibit a linear dose-response. Emerging evidence suggests that the model alkylating agents methyl- and ethylmethanesulfonate and methylnitrosourea (MNU) and ethylnitrosourea observe a nonlinear dose-response with a no observed genotoxic effect level (NOGEL). Follow-up mechanistic studies are essential to understand the mechanism of cellular tolerance and biological relevance of such NOGELs. MNU is one of the most mutagenic simple alkylators. Therefore, understanding the mechanism of mutation induction, following low-dose MNU treatment, sets precedence for weaker mutagenic alkylating agents. Here, …
Modulation of folic acid bioaccessibility by encapsulation in pH-responsive gated mesoporous silica particles
2015
[EN] A study on the controlled release of folic acid (FA) from pH-responsive gated mesoporous silica particles (MSP) is reported. The MCM-41 support was synthesized using tetraethyl orthosilicate (TEOS) as hydrolytic inorganic precursor and the surfactant hexadecyltrimethylammonium bromide (CTAB) as porogen species. Calcination of the mesostructured phase resulted in the starting solid. This solid was loaded with FA to obtain the initial support S0. Moreover, this FA-loaded material was further functionalized with 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (N3) in order to obtain the gated polyamine-functionalised material S1. Solids S0 and S1 were characterized using standar…
Low-cost materials for boron adsorption from water
2012
[EN] Knowing the affinity of boron aqueous species for cis-diol organic groups, five different hybrid materials have been prepared by anchoring glucose groups onto the surface of silica matrices with a different surface topology: UVM-7 bimodal mesoporous silica, UVM-11 unimodal non-templated mesoporous silica, commercial silica fume and two silica xerogels with pores within the mesoporous range (13-50 nm). After optimizing the experimental conditions, a comparison was made of the boron adsorption capacities in water. The relationship of the structural and functionalization parameters is discussed and the importance of the surface topology in the final adsorption behaviour is revealed. Hence…
Stability of different mesoporous silica particles during an in vitro digestion
2016
Mesoporous silica materials have the ability to entrap drugs, nutrients and functional biomolecules and can be able to act as smart delivery systems capable to control and target the release of their cargo in a particular part of the gastrointestinal tract when administrated orally. However, the aptness of these encapsulation supports in in vivo oral controlled release relies on their chemical stability through the digestive tube. In this context, we have evaluated the stability of four different mesoporous silica particles, frequently used as encapsulating supports, during an in vitro digestion process comprising buccal, stomach and intestinal phases. Results showed that after 4 h of diges…
Manipolazione tipologica. Upcycling degli edifici ERP di Tor Bella Monaca a Roma
2020
Il gruppo, sin dalle prime fasi del progetto, ha lavorato con la volontà di cogliere, nella collaborazione e nel dialogo multidisciplinare e disciplinare, una opportunità di crescita culturale e scientifica per il raggiungimento di soluzioni condivise, operando in sinergia, mettendo a sistema le conoscenze, evitando la frammentazione e ottimizzando le diverse specificità nello sviluppo delle idee. La rigenerazione del comparto oggetto di questo studio ha assunto come enunciato quattro azioni elementari come strumenti operativi declinati alla scala urbana, a quella architettonica e a quella delle soluzioni tecnologiche per plasmare una nuova identità urbana: includere, sottrarre, aggiungere …
"Table 4" of "Measurement of prompt photon production in $\sqrt{s_\mathrm{NN}} = 8.16$ TeV $p$+Pb collisions with ATLAS"
2019
The nuclear modification factor R_pPb for prompt, isolated photons with rapidity in (1.09,1.90).