Nachum S.,University of Cambridge |
Fleck N.A.,University of Cambridge |
Ashby M.F.,University of Cambridge |
Colella A.,CSGI |
Matteazzi P.,MBN Nanomaterialia S.p.A.
Materials Science and Engineering A | Year: 2010
The mechanical properties and electrical resistivity of nanocrystalline copper reinforced by 1. vol.% and 5. vol.% of nano-alumina particles have been measured. The composites were prepared by ball-milling and consolidated by a combination of hot extrusion and HIPing. The uniaxial tensile and compressive strengths are comparable for each composite, and an elastic, ideally plastic response is observed. Shear bands, of width a few microns, accompany plastic deformation. A number of microstructural characterisation tools were used to reveal that grain boundary strengthening and dispersion strengthening are the dominant strengthening mechanisms. Nano-indentation measurements reveal a size effect in hardness. The electrical resistivity is almost double that of pure oxygen free copper and this is mainly ascribed to the presence of dissolved iron. © 2010 Elsevier B.V.
Nappini S.,CNR Institute of Materials |
Magnano E.,CNR Institute of Materials |
Bondino F.,CNR Institute of Materials |
Pis I.,CNR Institute of Materials |
And 8 more authors.
Journal of Physical Chemistry C | Year: 2015
Magnetic nanoparticles (MNPs) have shown exceptional potential for several biological and clinical applications. However, MNPs must be coated by a biocompatible shell for such applications. The aim of this study is to understand if and how the surface charge and coating can affect the electronic and magnetic properties of CoFe2O4 MNPs. The role of the surface on the total magnetic moment of MNPs is a controversial issue, and several effects can contribute to make it deviate from the bulk value, including the charge, the nature of the coating, and also the synthetic technique. Positively and negatively charged uncoated CoFe2O4 NPs as well as citrate-coated NPs were prepared by soft chemistry synthesis. The electronic properties and cationic distribution of CoFe2O4 NPs were probed by X-ray absorption spectroscopy (XAS), X-ray magnetic circular dichroism (XMCD), and X-ray photoemission spectroscopy (XPS) techniques and confirmed by theoretical simulations. The overall magnetic behavior and the hyperthermic properties were evaluated by magnetometry and calorimetric measurements, respectively. The results show that all of the investigated CoFe2O4 NPs have high magnetic anisotropy energy, and the surface charge and coating do not influence appreciably their electronic and magnetic properties. In addition, the citrate shell improves the stability of the NPs in aqueous environment, making CoFe2O4 NPs suitable for biomedical applications. © 2015 American Chemical Society.
Nappini S.,CSGI |
Bonini M.,CSGI |
Bombelli F.B.,CSGI |
Pineider F.,Consortium for Science and Technology of Materials |
And 3 more authors.
Soft Matter | Year: 2011
The paper describes the effect of a low-frequency alternating magnetic field (LF-AMF) on the permeability and release properties of large (LUVs) and giant (GUVs) unilamellar vesicles loaded with citrate coated cobalt ferrite nanoparticles (NPs). The citrate shell allows a high loading of NPs in lipid vesicles without modifying their magnetic properties. The increase of magnetic LUVs permeability upon exposure to LF-AMF has been evaluated as the fluorescence self-quenching of carboxyfluorescein (CF) entrapped inside the liposome aqueous pool. Liposome leakage has been monitored as a function of field frequency, time exposure and concentration of the citrate coated NPs. Confocal Laser Scanning Microscopy (CLSM) experiments performed on magnetic GUVs labeled with the fluorescent probe DiIC 18 and loaded with Alexa 488-C5-maleimide fluorescent dye provided insights on the release mechanism induced by LF-AMF. The results show that LF-AMF strongly affects vesicles permeability, suggesting the formation of pores in the lipid bilayer due to both hyperthermic effects and nanoparticle oscillations in the vesicles pool at the applied frequency. The behaviour of these magnetic vesicles in the presence of LF-AMF makes this system a good candidate for controlled drug delivery. © 2011 The Royal Society of Chemistry.
News Article | November 7, 2016
Mr. Vernon (Russ) Sanford is a retired Navy Medical Service Corps Officer who brings a combined 40+ years of experience working across several healthcare disciplines in support of multiple federal health agencies to include the Military Health System (now known as the Defense Health Agency), the Department of Veterans Affairs, and various agencies within the Department of Health and Human Services. Russ brings a unique combination of skills in healthcare information technology, business development, capture management, operations and service delivery management within the federal market and has experience working with small, mid-sized and large companies. In addition, Russ has a proven record of facilitating long term business relationships with both customers and industry thought leaders. Ms. Tiffany Comey is responsible for strategic planning and implementation of the company’s operations. Ms. Comey will focus on formulating policies, compliance, managing the daily operations of talent management, administration and other functional departments. Tiffany brings over 20 years of experience managing law firm operations, Human Resources, and overall firm operations and profitability. In addition, Tiffany has demonstrated outstanding leadership and execution in operations and management. CTIS, CEO, Mr. Raj Shah says “I am very pleased that Russ and Tiffany are joining our team. They share our values and our focus on innovation. They both have proven track records of extraordinary leadership throughout their careers. Together, we look forward to increased growth, innovation and providing the highest quality of care to serve patients better.” For more information, please contact us at info(at)ctisinc(dot)com or visit the CTIS, Inc. website at http://www.ctisinc.com. About CTIS: CTIS is a wholly owned subsidiary of CSGI. CTIS, Inc., is a leader in developing innovative solutions for the health industry across various areas of the health industry. We are a CMM I Level 3-rated small business, serving the Federal Government, commercial, and non-profit organizations in the National Capital Area for more than 25 years. CTIS has provided informatics solutions and other support services to over 30 NIH projects with the goal to provide outcome-driven IT solutions that improve productivity, efficiency, safety, and privacy.
Nappini S.,CSGI |
Fogli S.,CSGI |
Castroflorio B.,CSGI |
Bonini M.,CSGI |
And 2 more authors.
Journal of Materials Chemistry B | Year: 2016
The final fate of nano-scaled drug delivery systems into the body is highly affected by their interaction with proteins in biological fluids (serum, plasma, etc.). Nanocarriers dispersed in biological fluids bear a protein "corona" that covers their surface. Thus, it is extremely important to evaluate the drug release efficiency also in the biological environment where protein-nanocarrier complexes are formed. The purpose of this work is to determine how drug release from lipid vesicle carriers is influenced by the interaction with serum proteins, highlighting the importance to test the effectiveness of such systems in the biological milieu. In particular, this paper describes the magnetically triggered release behaviour of magnetoliposomes (MLs) dispersed both in aqueous physiological buffer and in bovine serum at two different concentrations (10% and 55% v/v) upon exposure to a low-frequency alternating magnetic field (LF-AMF). We studied the release from MLs loaded with two types of magnetic nanoparticles (MNPs): citrate coated Fe3O4 and oleic acid coated γ-Fe2O3. The permeability in the above-mentioned fluids was evaluated in terms of the fluorescence self-quenching of carboxyfluorescein (CF) entrapped inside the liposome aqueous pool. The results showed a strong reduction of the release in biological fluids, in particular at high serum concentration. We related this decrease to the formation of protein-liposome complexes that, under LF-AMF exposure, are subjected to destabilization and tend to form aggregates. Our results clearly highlight the importance of testing the release efficiency of self-assembled drug delivery systems in biological fluids, in order to understand their behaviour in the presence of proteins and biomolecules. © 2015 The Royal Society of Chemistry.
Stockmann T.J.,University Paris Diderot |
Noel J.-M.,University Paris Diderot |
Ristori S.,CSGI |
Combellas C.,University Paris Diderot |
And 3 more authors.
Analytical Chemistry | Year: 2015
Oscillating chemical reactions, encapsulated within artificial vesicles have been demonstrated as a powerful analogy of living cells for the investigation of chemical communication and morphogenesis. However, little is understood with regards to the influence of confinement on the reactivity of such systems. Herein, the effect of confinement on the Belousov-Zhabotinsky (BZ) oscillating reaction in bulk solution, (employing ferroin as a catalyst and malonic acid as the organic substrate) is investigated using scanning electrochemical microscopy (SECM) toward different insulating surfaces such as glass, silanized glass, or PTFE. An unexpected increase in the amplitude of the BZ reaction at a tip-substrate distance of ∼12-15 μm is observed. By simulating different reaction mechanisms, from simple EC' catalysis to more sophisticated Oregonator or even an 11-reaction scheme, it is shown that such behavior reveals the intervention of redox catalysis processes and particularly the short-lived highly reactive radical intermediate BrO2 • indirectly detected at micromolar concentrations. The reinspection of the EC' mechanism shows that the homogeneous catalysis route is confirmed and kinetically characterized from SECM toward an insulating substrate, with promising potentiality in many systems. More specifically to the complex chemical case of BZ reactions, the mechanism is understood from the envelope curves of the oscillations, which are assessed in the absence of the oscillation (absence of organic substrate). © 2015 American Chemical Society.
Tomasi R.,University Pierre and Marie Curie |
Tomasi R.,ESPCI ParisTech |
Noel J.-M.,ESPCI ParisTech |
Zenati A.,University Pierre and Marie Curie |
And 5 more authors.
Chemical Science | Year: 2014
Long-range chemical communication takes place over micrometer distance within different biological organisms and biomimetic chemical micro-compartments). A proper model for studying this phenomenon could rely on three features, namely (i) the compartmentalization of chemical information (using microfluidics), (ii) a stable emitter of periodic chemical signals inside compartments (Belousov-Zhabotinsky oscillating reaction) and (iii) a suitable spatio-temporal monitoring of the emitted chemical signal. In this paper we study chemical transmission across the interface between two immiscible liquids, eventually in the presence of lipid, by local electrochemical probing. We show that chemical information is transmitted either by direct transfer of redox active species and or by interfacial electron transfer. Insights obtained by electrochemical measurements, together with numerical simulations, are then used to transpose the communication across a phospholipid bilayer among oscillators compartmentalized in liposomes and dispersed in a water medium. The procedure for the successful generation of these cell-like compartments through microfluidics is reported here for the first time. © 2014 the Partner Organisations.
Georgiou E.P.,Catholic University of Leuven |
Achanta S.,Falex Tribology NV |
Dosta S.,University of Barcelona |
Fernandez J.,University of Barcelona |
And 4 more authors.
Applied Surface Science | Year: 2013
A nanostructured cermet coating consisting of alumina dispersed in a Fe-Cu-Al matrix was deposited by supersonic spraying. The experiments revealed a strong effect of deposition parameters and chemical composition of the powders on the structural characteristics of the Fe-Cu-Al + Al2O3 sprayed cermet. This cermet is made up of complex metallurgical phases as revealed by electron microscopy and X-ray diffraction. The mechanical properties of the different phases detected were determined by nanoindentation. Finally, the friction and wear behavior of this nanostructured sprayed cermet were compared to the ones of benchmark materials. It was found that the Fe-Cu-Al + Al2O3 cermet coating exhibit better tribological properties than the benchmark materials thanks to an appropriate balance of hard and soft phases, and a nanostructuring. The wear mechanism was investigated to establish a 'structure-property' relationship for this type of nanostructured cermet coatings. © 2013 Elsevier B.V.
Busi E.,University of Siena |
Vitiello G.,CSGI |
Vitiello G.,University of Naples Federico II |
Niccoli M.,University of Naples Federico II |
And 4 more authors.
Biochimica et Biophysica Acta - Biomembranes | Year: 2013
The mechanism underlying the ionophoric activity of CyPLOS (cyclic phosphate-linked oligosaccharide, 2), a carbohydrate-based synthetic ion transporter decorated with four tetraethylene glycol (TEG) chains, has been investigated by an integrated electron spin resonance (ESR) approach. The mode of interaction of the ionophore with lipid bilayers has been studied by quantitatively analyzing the perturbations in the ESR spectrum of an ad hoc synthesized spin-labeled CyPLOS analog (6), and, in parallel, in the spectra of spin-labeled lipids mixed with 2. The results point to a positioning of the cyclic saccharide backbone close to the lipid headgroups, largely exposed to the aqueous medium. The TEG chains, carrying a terminal benzyl group, are deeply inserted among the lipid acyl chains, showing good mobility and flexibility. As a consequence, the order of the acyl chain packing is significantly reduced, and water penetration in the bilayer is enhanced. The resulting asymmetric perturbation of the bilayer leads to its local destabilization, thus facilitating, through a non-specific mechanism, the ion transport through the membrane. © 2013 Elsevier B.V.
Jing D.,Syracuse University |
He J.,Syracuse University |
Bonini M.,National institute for astrophysics |
Brucato J.R.,CSGI |
Vidali G.,Syracuse University
Journal of Physical Chemistry A | Year: 2013
We studied the formation of deuterated water on an amorphous silicate surface held at low temperature (10 K < T < 40 K). The surface is first characterized by using Ar+ ion bombardment, and preferential sputtering of oxygen is found. Sputtering creates oxygen vacancies in the surface region that can be filled by deposition of atomic oxygen. The conditions used in the experiment are meant to make it relevant to the study of the initial stages of water formation on dust grains in interstellar space. By changing the D/O ratio of atomic beams of deuterium and oxygen at thermal energy and the temperature of the sample during deposition, we show that the routes to the formation of D2O2 can be untangled and, under certain circumstances, the net yield of D2O2 can be suppressed. The formation efficiency for water and other molecules is then estimated. © 2013 American Chemical Society.