The impact of the discreteness of low-fluence ion beam processing on the spatial architecture of GaN nanostructures fabricated by surface charge lithography

Abstract Background After the golden age of antibiotic discovery, bacterial infections still represent a major challenge for public health worldwide. The biofilm mode of growth is mostly responsible for chronic infections that current therapeutics fail to cure and it is well-established that novel strategies must be investigated. Particulate drug delivery systems are considered as a promising strategy to face issues related to antibiotic treatments in a biofilm context. Particularly, poly-lactic acid (PLA) nanoparticles present a great interest due to their ability to migrate into biofilms thanks to their submicronic size. However, questions still remain unresolved about their mode of action in biofilms depending on their surface properties. In the current study, we have investigated the impact of their surface charge, firstly on their behavior within a bacterial biofilm, and secondly on the antibiotic delivery and the treatment efficacy. Results Rifampicin-loaded PLA nanoparticles were synthetized by nanoprecipitation and characterized. A high and superficial loading of rifampicin, confirmed by an in silico simulation, enabled to deliver effective antibiotic doses with a two-phase release, appropriate for biofilm-associated treatments. These nanoparticles were functionalized with poly-l-lysine, a cationic peptide, by surface coating inducing charge reversal without altering the other physicochemical properties of these particles. Positively charged nanoparticles were able to interact stronger than negative ones with Staphylococcus aureus, under planktonic and biofilm modes of growth, leading to a slowed particle migration in the biofilm thickness and to an improved retention of these cationic particles in biofilms. While rifampicin was totally ineffective in biofilms after washing, the increased retention capacity of poly-l-lysine-coated rifampicin-loaded PLA nanoparticles has been associated with a better antibiotic efficacy than uncoated negatively charged ones. Conclusions Correlating the carrier retention capacity in biofilms with the treatment efficacy, positively charged rifampicin-loaded PLA nanoparticles are therefore proposed as an adapted and promising approach to improve antibiotic delivery in S. aureus biofilms.

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Functional Modification of Cellulose Acetate Microfiltration Membranes by Supercritical Solvent Impregnation

Molecules ◽

10.3390/molecules26020411 ◽

2021 ◽

Vol 26 (2) ◽

pp. 411

Author(s):

Irena Zizovic ◽

Marcin Tyrka ◽

Konrad Matyja ◽

Ivana Moric ◽

Lidija Senerovic ◽

...

Keyword(s):

Cellulose Acetate ◽

Ion Beam ◽

Antibacterial Properties ◽

Cross Flow ◽

Batch Mode ◽

Impregnation Process ◽

Supercritical Solvent ◽

Cross Flow Filtration ◽

Microfiltration Membranes ◽

The Impact

This study investigates the modification of commercial cellulose acetate microfiltration membranes by supercritical solvent impregnation with thymol to provide them with antibacterial properties. The impregnation process was conducted in a batch mode, and the effect of pressure and processing time on thymol loading was followed. The impact of the modification on the membrane’s microstructure was analyzed using scanning electron and ion-beam microscopy, and membranes’ functionality was tested in a cross-flow filtration system. The antibiofilm properties of the obtained materials were studied against Staphyloccocus aureus and Pseudomonas aeruginosa, while membranes’ blocking in contact with bacteria was examined for S. aureus and Escherichia coli. The results revealed a fast impregnation process with high thymol loadings achievable after just 0.5 h at 15 MPa and 20 MPa. The presence of 20% of thymol provided strong antibiofilm properties against the tested strains without affecting the membrane’s functionality. The study showed that these strong antibacterial properties could be implemented to the commercial membranes’ defined polymeric structure in a short and environmentally friendly process.

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Resistless Patterning of Magnetic Storage Media Using Ion Projection Structuring

MRS Proceedings ◽

10.1557/proc-705-y3.4 ◽

2001 ◽

Vol 705 ◽

Cited By ~ 2

Author(s):

A. Dietzel ◽

R. Berger ◽

H. Grimm ◽

C. Schug ◽

W. H. Bruenger ◽

...

Keyword(s):

Process Development ◽

Ion Beam ◽

Silicon On Insulator ◽

Magnetic Storage ◽

Magnetic Islands ◽

Superlattice Structure ◽

Head Positioning ◽

Out Of Plane ◽

Set Up ◽

The Impact

AbstractCo/Pt thin film multilayers with strong perpendicular anisotropy and out-of-plane coercivities of 5-11 kOe were magnetically altered in areas of local ion beam interaction. The ion irradiations were performed by ion projection through silicon stencil masks fabricated by silicon on insulator (SOI) membrane technology. The ion projector at the Fraunhofer Institute for Silicon Technology (ISiT) was operated at 73 keV ion energy and with a 8.7- fold demagnification. After exposure to 3 × 1014Ar+/ cm2 magnetic islands smaller than 100 nm in diameter were resolved in the Co/Pt multilayersby means of magnetic force microscopy. The impact of different ion species (He+, Ar+ and Xe+) and ion energies (10 – 200 keV) on the multilayer structure was evaluated using Monte Carlo simulations. The ballistic interface intermixing was used to predict magnetic coercivity changes for various irradiation conditions. The simulations revealed that with 73 keV Ar+ and Xe+ ions the irradiation dose could be reduced by a factor of 100 and 400 respectively in comparison to 73 keV He+which was verified in the experiments. X-ray reflectivity measurements confirmed that the Co/Pt superlattice structure is slightly weakened during the irradiation and that the surface smoothness of the media is preserved. Using the Ion Projection Process Development Tool (PDT) at IMS-Vienna concentric data tracks including head positioning servo informations were patterned onto a 1” IBM microdrive™ glass disk which was coated with Co/Pt multilayers. In a single exposure step several tracks within an exposure field of 17 mm in diameter were structured by 2 × 1015He+/ cm2 at 45 keV using a 4- fold demagnification set-up.

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Diamond-Like Carbon Coating—It'S Application for Polymeric Substrates

MRS Proceedings ◽

10.1557/proc-239-647 ◽

1991 ◽

Vol 239 ◽

Author(s):

Fred M. Kimock ◽

Alex J. Hsieh ◽

Peter G. Dehmer ◽

Pearl W. Yip

Keyword(s):

High Speed ◽

Protective Coatings ◽

Ion Beam ◽

Chemical Exposure ◽

Optical Systems ◽

Impact Behavior ◽

Organic Liquids ◽

Diamond Like Carbon ◽

Dlc Coating ◽

The Impact

ABSTRACTWe report on a recently commercialized Diamond-Like Carbon (DLC) coating that has been deposited on polycarbonate at near room temperature, via a unique ion beam system. Aspects of high speed impact behavior, chemical resistance, abrasion resistance, and thermal stability of the coating are examined. Results of scanning electron microscopy studies indicate that adhesion of the DLC coating is very good; no delamination of the coating was found on ballistically tested specimens. The well-bonded DLC coating did not cause the impact performance of polycarbonate to become brittle. Chemical exposure test results show that the DLC coating is capable of protecting polycarbonate from chemical attack by aggressive organic liquids. These ion beam deposited DLC coatings have considerable potential as protective coatings for optical systems.

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The Impact of Surface Charge on the Mechanical Behavior of High-Porosity Chalk

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-012-0317-z ◽

2012 ◽

Vol 46 (5) ◽

pp. 1073-1090 ◽

Cited By ~ 40

Author(s):

M. Megawati ◽

A. Hiorth ◽

M. V. Madland

Keyword(s):

Mechanical Behavior ◽

Surface Charge ◽

High Porosity ◽

The Impact

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Thin Solid Film Electrolyte and Its Impact on Electrode Polarization in Solid Oxide Fuel Cells Studied by Three-Dimensional Microstructure-Scale Numerical Simulation

Energies ◽

10.3390/en13195127 ◽

2020 ◽

Vol 13 (19) ◽

pp. 5127

Author(s):

Tomasz A. Prokop ◽

Grzegorz Brus ◽

Shinji Kimijima ◽

Janusz S. Szmyd

Keyword(s):

Focused Ion Beam ◽

Ion Beam ◽

Three Dimensional ◽

Reaction Rates ◽

Solid Oxide ◽

Scale Model ◽

Electrode Polarization ◽

Computational Domain ◽

Oxide Fuel ◽

The Impact

In this work, a three-dimensional microstructure-scale model of a Solid Oxide Fuel Cell’s Positive-Electrolyte-Negative assembly is applied for the purpose of investigating the impact of decreasing the electrolyte thickness on the magnitude, and the composition of electrochemical losses generated within the cell. Focused-Ion-Beam Scanning Electron Microscopy reconstructions are used to construct a computational domain, in which charge transport equations are solved. Butler–Volmer model is used to compute local reaction rates, and empirical relationships are used to obtain local conductivities. The results point towards three-dimensional nature of transport phenomena in thin electrolytes, and electrode-electrolyte interfaces.

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Laser-assisted atom probe tomography of semiconductors: The impact of the focused-ion beam specimen preparation

Ultramicroscopy ◽

10.1016/j.ultramic.2018.03.001 ◽

2018 ◽

Vol 188 ◽

pp. 19-23 ◽

Cited By ~ 3

Author(s):

J. Bogdanowicz ◽

A. Kumar ◽

C. Fleischmann ◽

M. Gilbert ◽

J. Houard ◽

...

Keyword(s):

Atom Probe Tomography ◽

Focused Ion Beam ◽

Ion Beam ◽

Atom Probe ◽

Beam Specimen ◽

Specimen Preparation ◽

The Impact

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Structure and Properties of Zirconium Alloy after Modification by Pulse Ion Beam

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.302.82 ◽

2013 ◽

Vol 302 ◽

pp. 82-85 ◽

Cited By ~ 4

Author(s):

E.V. Berezneeva ◽

N.S. Pushilina ◽

D.V. Berezneev ◽

I.P. Chernov ◽

A.M. Lider ◽

...

Keyword(s):

Pulse Duration ◽

Current Density ◽

Pulse Energy ◽

Zirconium Alloy ◽

Phase State ◽

Ion Beam ◽

Experimental Results ◽

Structure And Properties ◽

Structure Phase ◽

The Impact

Experimental results on the impact of pulsed ion beam with parameters the pulse duration 80 ns, energy of 200 keV and current density 120 А/сm2 , pulse energy ~ 1,5 J/сm2 on the alloy Zr1Nb on structure – phase state of the alloy of zirconium Zr1Nb. It is shown that such irradiation leads to changes in the structure of the surface and the hardening of the material.

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How to Simulate the Microstructure Induced by a Nuclear Reactor with an Ion Beam Facility : DART

MRS Proceedings ◽

10.1557/proc-1215-v13-03 ◽

2009 ◽

Vol 1215 ◽

Author(s):

Laurence Luneville ◽

David Simeone ◽

Gianguido Baldinozzi ◽

Dominique Gosset ◽

yves serruys

Keyword(s):

Cross Sections ◽

Nuclear Reactor ◽

Nuclear Reactions ◽

Ion Beam ◽

Fast Neutrons ◽

Relaxation Processes ◽

Pressurized Water ◽

Water Reactors ◽

Displacement Per Atom ◽

The Impact

AbstractEven if the Binary Collision Approximation does not take into account relaxation processes at the end of the displacement cascade, the amount of displaced atoms calculated within this framework can be used to compare damages induced by different facilities like pressurized water reactors (PWR), fast breeder reactors (FBR), high temperature reactors (HTR) and ion beam facilities on a defined material. In this paper, a formalism is presented to evaluate the displacement cross-sections pointing out the effect of the anisotropy of nuclear reactions. From this formalism, the impact of fast neutrons (with a kinetic energy En superior to 1 MeV) is accurately described. This point allows calculating accurately the displacement per atom rates as well as primary and weighted recoil spectra. Such spectra provide useful information to select masses and energies of ions to perform realistic experiments in ion beam facilities.

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Influence of Domain Structure on Magnetoresistance in Perovskite Manganite Grain Boundary Junctions

MRS Proceedings ◽

10.1557/proc-674-u3.7 ◽

2001 ◽

Vol 674 ◽

Cited By ~ 1

Author(s):

Robert Gunnarsson ◽

Anatoli Kadigrobov ◽

Zdravko Ivanov

Keyword(s):

Grain Boundary ◽

Temperature Dependence ◽

Focused Ion Beam ◽

Domain Walls ◽

Ion Beam ◽

Perovskite Manganite ◽

Current Voltage ◽

Single Grain ◽

Current Voltage Characteristics ◽

The Impact

ABSTRACTWe have been able to deduce a temperature dependence of the built-in potential in La2/3Sr1/3MnO3 grain boundary junctions. This has been performed by trimming a single grain boundary down to 1μm width with a focused ion-beam. We can thereby see the impact of single domain walls on the magnetoresistance and the current-voltage characteristics. We have also demonstrated the effect of averaging as we increased the number of junctions.

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