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International audience; Surface-enhanced Raman scattering (SERS), based on the enhancement of the Raman signal of molecules positioned within a few nanometres from a structured metal surface, is ideally suited to provide bacterial-specific molecular fingerprints which can be used for analytical purposes. However, for some complex structures such as bacteria, the generation of reproducible SERS spectra is still a challenging task. Among the various factors influencing the SERS variability (such as the nature of SERS-active substrate, Raman parameters and bacterial specificity), we demonstrate in this study that the environment of Gram-positive and Gram-negative bacteria deposited on ultra-thin silver films also impacts the origin of the SERS spectra. In the case of densely packed bacteria, the obtained SERS signatures were either characteristic of the secretion of adenosine triphosphate for Staphylococcus aureus (S. aureus) or the cell wall and the pili/flagella for Escherichia coli (E. coli), allowing for an easy discrimination between the various strains. In the case of isolated bacteria, SERS mapping together with principal component analysis revealed some variabilities of the spectra as a function of the bacteria environment and the bactericidal effect of the silver. However, the variability does not preclude the SERS signatures of various E. coli strains to be discriminated.

Since their discovery, antibiotics have helped treat diseases prior to which many were untreatable, saving millions of lives. However, due to the overuse of antibiotics in medicine and agriculture, the advent of resistant strains of bacteria followed shortly after. The current antibiotic resistance crisis is bringing humanity closer to a post-antibiotic era, when all the advancements made by modern medicine could easily be reversed. Pseudomonas aeruginosa is a Gram-negative, rod-shaped bacterium, ubiquitous owing to its minimal nutritional and growth requirements. P. aeruginosa is one of the pathogens included in the priority list of the WHO, being assessed as critical due to its high antimicrobial resistance, leaving only a few effective treatment options to combat it. As an opportunistic pathogen, P. aeruginosa establishes infection in immunocompromised patients, primarily in hospital settings. In order to initiate infection, it requires several virulence factors that mediate the invasion of the pathogen into host cells. Owing to the multiple resistance mechanisms of P. aeruginosa, it has developed resistance to most classes of antibiotics. Due to its increased resistance, treating P. aeruginosa infections is a great challenge for clinicians. Several β-lactam/β-lactamase combinations have been approved and are available as treatment options, which overall show high efficacy against P. aeruginosa. Moreover, novel antibiotics are currently in development as possible antipseudomonal agents, including a Pseudomonas-specific formulation. In addition, new strategies such as bacteriophage therapy, pyocins or the inhibition of the quorum sensing system are being investigated for the treatment of P. aeruginosa infections.

In the last few decades, methicillin-resistant Staphylococcus aureus (MRSA) strains have become a serious health care problem. However, in the European Union/European Economic Area countries the pr...

In the last few decades, methicillin-resistant

Designing hybrid nanomaterials that exhibit multiple mechanisms of antibacterial action provides a new paradigm in the fight against resistant bacteria. Herein, we present such a new hybrid nanomaterial which integrates the antibacterial and physico-chemical properties of silver nanoparticles, graphene oxide and chitosan biopolymer. The formation, stability and structure of the integrated three-component chitosan-silver nanoparticles–graphene oxide (chit–AgNPs–GO) nanomaterial is analyzed by UV–vis extinction spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. The antibacterial activity is evaluated against two representative methicillin-resistant Staphylococcus aureus (MRSA) strains (UCLA 8076 and 1190R) and relative to individual components (GO, chit–GO, AgNPs–GO) by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The three-component nanocomposites (chit–AgNPs–GO) exhibit higher antibacterial activity than most of the antibacterial agents based on AgNPs or AgNPs–GO reported so far and, more interestingly, their activity can be controlled by the ratio between the amount of chitosan and AgNPs–GO. The results presented in this study demonstrate the promising potential of the chit–AgNps–GO hybrids as effective nanomaterial to fight against the bacterial infections.

The paper discusses a part of an industrial project which can be solved by mechatronic design method. In general, it follows VDI Guidelines 2206 and 2143, applying a model-based design tool. The objective of the project was to design and construct of a new state of the art pinion-engaging mechanism for starter motors. The pinion-engaging mechanism is a cam follower mechanism which contains the following parts: dc servo motor, rotational to translational transducer and the drive pinion. The rotational to translational transducer can be realized by designing a cylindrical roller follower mechanism. The goal of this paper is to present a mechanism design process and a test bench of the achieved construction. Some aspects of the kinematic relationships of the motion control, including electromechanical modeling are considered.

The aim of this study is to investigate the antibacterial efficiency of pluronic-coated silver nanoparticles when, instead of commonly explored spherical nanoparticles, anisotropic nanoparticles (nanoprisms) enveloped in a biocompatible polymer are used. In the first step we successfully synthesized silver nanoprisms with edge length between 30 and 50 nm and thickness between 4 and 6 nm exhibiting well-resolved localized surface plasmon resonances (LSPR) at 615, 443 and 335 nm. To endow with colloidal and morphological stability required in biological environment, the as-prepared silver nanoprisms were coated with pluronic F-127—a synthetic triblock copolymer consisting of PEO (poly(ethylene oxide))–PPO (poly(propylene oxide))–PEO (poly(ethylene oxide)) chains. The bactericidal effects of pluronic-coated silver nanoprisms were evaluated against two methicillin-resistant Staphylococcus aureus (MRSA) strains (UCLA 8076 and 1190R) by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The strong antibacterial activity we found can be explained by considering that triangular nanoprisms exhibit crystalline facets of higher reactivity and, presumably, a higher rate of ions release from their tips and edges compared to other shapes of nanoparticles.

The goal of this paper is to present an inductance measurement method, and an electromechanical model of the pinion-engaging mechanism for the starter motors. The pinionengaging mechanism is the system of components (solenoid switch, pinion-engaging lever, and overrunning clutch with drive pinion) that engages the drive pinion of the starter motor with the ring gear of the internal combustion engine. The actuator of the pinion-engaging mechanism consists of two concentric iron core coils. The coils are excited by relatively high currents. The electromechanical model of the pinion-engaging mechanism requires inductance of the solenoid and its derivative depending on the position of the iron core.

The goal of this paper is to model electro-dynamically the pinion-engaging mechanism (PEM) of starter motors. The purpose of the PEM is to switch a high current by means of relatively low control current. The PEM is the system of components (solenoid switch, pinion-engaging lever, and overrunning clutch with drive pinion) that engages the drive pinion with the ring gear. The solenoid switches consist of a pull-in winding and a hold-in winding and a movable iron core. The electro-dynamic model of the solenoid switch contains the inductance and its partial derivatives which depend on the current and the position of the solenoid armature. An electromechanical measurement method is proposed to determine the inductance and its derivative for various positions of the solenoid switch. The experimental results are implemented in the electro-dynamic model using energy-based modeling applying the Euler-Lagrange formalism.

In this paper the measurement of the inductance and electromagnetic force of an electromagnetic actuator is described. The paper proposes a method for the electromechanical determination of the inductance of an electromagnet and its derivative for various positions of the iron core.

This paper presents an example for successful cooperation between universities and industrial companies. Due to the comprehensive preparatory work of the top-level managements of both the University of Miskolc, Hungary, and the Bosch consortium, the Robert Bosch Department of Mechatronics has been established within the Faculty of Mechanical Engineering. The operation of the Robert Bosch Department of Mechatronics will be facilitated by the four Bosch companies in the region and the German Federation of Foundations during the next three years, and subsequently it will be taken over by the University of Miskolc. The main objectives of the cooperation are the application and dissemination of the latest technical and scientific know-how in the fields of research, professional educational programs and widespread application of mechatronics, including the strengthening of practice-oriented training programs an meeting the recruitment requirements of the Bosch companies in the region in terms of engineers. The paper covers the achievements and the future plans of the Department.

The approach of combining different mechanisms of antibacterial action by designing hybrid nanomaterials provides a new paradigm in the fight against resistant bacteria. Here, we present a new method for the synthesis of silver nanoparticles enveloped in the biopolymer chitosan. The method aims at the production of bionanocomposites with enhanced antibacterial properties. We find that chitosan and silver nanoparticles act synergistically against two strains of Gram-positive Staphylococcus aureus (S. aureus). As a result the bionanocomposites exhibit higher antibacterial activity than any component acting alone. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of the chitosan-silver nanoparticles synthesized at 0 °C were found to be lower than those reported for other types of silver nanoparticles. Atomic force microscopy (AFM) revealed dramatic changes in morphology of S. aureus cells due to disruption of bacterial cell wall integrity after incubation with chitosan-silver nanoparticles. Finally, we demonstrate that silver nanoparticles can be used not only as antibacterial agents but also as excellent plasmonic substrates to identify bacteria and monitor the induced biochemical changes in the bacterial cell wall via surface enhanced Raman scattering (SERS) spectroscopy.