Multilayer Smart Holographic Label with Integrated RFID for Product Security and Monitoring.

Counterfeiting presents a major economic problem and an important risk for the public health and safety of individuals and countries. To make the counterfeiting process more difficult, and to ensure efficient authentication, a solution would be to attach anti-counterfeit labels that include a radio frequency identification (RFID) element to the products. This can allow real-time quality check along the entire supply chain. In this paper we present the technology optimized to obtain a multilayer holographic label with a high degree of security, patterned on a thin zinc sulfide film of a semi-transparent holographic foil rather than on the standard substrate for diffractive optical elements (metallized foil). The label is applied onto the product surface or packaging for anti-counterfeit protection. The developed multilayer structure contains various elements such as: a holographic background, nanotext-type elements, holographic elements, and an RFID antenna. The employed semi-transparent holographic foil offers the RFID antenna the possibility to transmit the electromagnetic signal through the label and thus to maximize the antenna footprint, achieving up to 10 m reading distance, with a 6 cm × 6 cm label, much smaller than the commercial standard (minimum 10 cm × 10 cm).

Selective Mid-IR Metamaterial-Based Gas Sensor System: Proof of Concept and Performances Tests.

In this paper, we propose a highly selective and efficient gas detection system based on a narrow-band IR metasurface emitter integrated with a resistive heater. In order to develop the sensor for the detection of specific gases, both the microheater and metasurface structures have been optimized in terms of geometry and materials. Devices with different metamaterial structures and geometries for the heater have been tested. Our prototype showed that the modification of the spectral response of metasurface-based structures is easily achieved by adapting the geometrical parameters of the plasmonic micro-/nanostructures in the metasurface. The advantage of this system is the on-chip integration of a thermal source with broad IR radiation with the metasurface structure, obtaining a compact selective radiation source. From the experimental data, narrow emission peaks (FWHM as low as 0.15 µm), corresponding to the CO2, CH4, and CO absorption bands, with a radiant power of a few mW were obtained. It has been shown that, by changing the bias voltage, a shift of a few tens of nm around the central emission wavelength can be obtained, allowing fine optimization for gas detection applications.

Influence of Random Plasmonic Metasurfaces on Fluorescence Enhancement.

One of the strategies employed to increase the sensitivity of the fluorescence-based biosensors is to deposit chromophores on plasmonic metasurfaces which are periodic arrays of resonating nano-antennas that allow the control of the electromagnetic field leading to fluorescence enhancement. While artificially engineered metasurfaces realized by micro/nano-fabrication techniques lead to a precise tailoring of the excitation field and resonant cavity properties, the technological overhead, small areas, and high manufacturing cost renders them unsuitable for mass production. A method to circumvent these challenges is to use random distribution of metallic nanoparticles sustaining plasmonic resonances, which present the properties required to significantly enhance the fluorescence. We investigate metasurfaces composed of random aggregates of metal nanoparticles deposited on a silicon and glass substrates. The finite difference time domain simulations of the interaction of the incident electromagnetic wave with the structures reveals a significant enhancement of the excitation field, which is due to the resonant plasmonic modes sustained by the nanoparticles aggregates. We experimentally investigated the role of these structures in the fluorescent behaviour of Rhodamine 6G dispersed in polymethylmethacrylate finding an enhancement that is 423-fold. This suggests that nanoparticle aggregates have the potential to constitute a suitable platform for low-cost, mass-produced fluorescent biosensors.

Carbapenemase-Producing Klebsiella pneumoniae in Romania: A Six-Month Survey.

This study presents the first characterization of carbapenem-non-susceptible Klebsiella pneumoniae isolates by means of a structured six-month survey performed in Romania as part of an Europe-wide investigation. Klebsiella pneumoniae clinical isolates from different anatomical sites were tested for antibiotic susceptibility by phenotypic methods and confirmed by PCR for the presence of four carbapenemase genes. Genome macrorestriction fingerprinting with XbaI was used to analyze the relatedness of carbapenemase-producing Klebsiella pneumoniae isolates collected from eight hospitals. Among 75 non-susceptible isolates, 65 were carbapenemase producers. The most frequently identified genotype was OXA-48 (n = 51 isolates), eight isolates were positive for blaNDM-1 gene, four had the blaKPC-2 gene, whereas two were positive for blaVIM-1. The analysis of PFGE profiles of OXA-48 and NDM-1 producing K. pneumoniae suggests inter-hospitals and regional transmission of epidemic clones. This study presents the first description of K. pneumoniae strains harbouring blaKPC-2 and blaVIM-1 genes in Romania. The results of this study highlight the urgent need for the strengthening of hospital infection control measures in Romania in order to curb the further spread of the antibiotic resistance.

Escherichia coli ST131 causing invasive infections in Romanian patients--a threat we can no longer ignore.

Escherichia coli sequence type ST131 is a major pandemic clonal group of drug-resistant extraintestinal pathogenic E. coli (ExPEC) involved in community-onset and healthcare-associated infections. Thus far, its presence in our area has been paid little attention. This is a preliminary study intended to detect ST131 among 87 clinical isolates retrieved from a larger and unpublished E. coli collection. The study isolates originated from various specimens associated with invasive infections (blood, deep surgical wounds/abscesses, tracheal aspirates, pleural fluid, cerebrospinal fluid, and peritoneal fluid) and were collected between 2010 and 2014. Based on the main inclusion criteria, resistance to extended-spectrum cephalosporins (ESCs) and/or fluoroquinolones (FQs), the isolates were distributed in three categories: isolates with resistance to FQs (20 isolates), to ESCs (8 isolates), and to FQs and ESCs (59 isolates), respectively. Polymerase chain reaction (PCR) -based assays were performed to determine the major phylogenetic groups, to predict the MLST ST131 status, and to detect the bla(CTX-M) content of the ESC-resistant isolates. Overall, the studied isolates derived from phylogenetic groups B2 (42 isolates), A (30 isolates), B1 (11 isolates), and D (4 isolates). Thirty-five isolates, originating from blood (26 isolates), deep wounds (6 isolates), tracheal aspirates (2 isolates), and cerebrospinal fluid (1 isolate), were identified as members of O25b:H4 ST131. Most of them displayed resistance to both ESCs and FQs and harboured group 1 bla(CRX-M) genes. The emergence of ST131 in our region can no longer be ignored. Focused attention to this lineage could reduce infection-related morbidity and antibiotic resistance.

Method of determination of light-scatterer distribution in edge-lit backlight units using an analytical approach.

We present a method to find the optimum distribution of scatterers in an edge-lit lightguide plate (LGP) for rendering a uniform distribution of the outcoupled light. We propose a simple mathematical model describing the light propagation in a waveguide with a distribution of scattering elements located on the lower surface of the waveguide. We have found a differential equation giving the distribution of scattering elements leading to a uniform irradiance along the LGP, and we propose a method to determine the value of the outcoupling coefficient of an individual scattering element from the irradiance (or radiance) measurements. We have verified the validity of this model by performing ray tracing simulations on an LGP with the scattering elements distributed according to the solution of the proposed differential equation, and we have found a quantitative agreement between the analytical results and the simulated ones. Also this model has been used to directly calculate the output power of a given embossed LGP.

The modulation of hela cells secretory patterns by invasive Shigella spp. and enteroinvasive E. coli bacterial cells and their soluble components.

Considering the important role of cytokines in the initiation and evolution of the inflammatory process induced by Shigella and EIEC strains, the purpose of this study was the characterization of the secretory patterns of HeLa cells induced by Shigella ssp. and EIEC strains and to link the obtained results with the invasiveness level of bacterial strains on this cellular line. During this study there were analyzed two EIEC strains and 12 strains of the following Shigella species: 2 Sh. flexneri 2a, 2 Sh. flexneri 3a, 2 Sh. flexneri 4a, 2 Sh. boydii, 2 Sh. sonnei strains isolated in Romania during 2005 from children with dysentery and diarrhoea and confirmed for their invasive ability by Sereny test. The level of the main pro and anti-inflammatory cytokines, IL-1 beta, IL-6, IL-10, IL-13, IL-17 and TNF-alpha induced by whole bacterial cultures as well as by their soluble mediators was determined by an ELISA test. Our results showed that HeLa cells can be used not only for the qualitative and quantitative assessment of Shigella and EIEC strains invasion ability, but also as a simple work procedure for the investigation of an in vitro complex crosstalk communication mechanisms that involves physical interactions between bacterial cells and epithelial cells (adhesins and complementary receptors) and pro- and anti-inflammatory molecules regulation.The majority of the analyzed Shigella serogroups, with the exception of Shigella sonnei and EIEC strains, inhibited the inflammatory response by reducing the expression of majority of pro-inflammatory cytokines, i.e., IL-1 beta, IL-6, TNF-alpha and IL-17. The reduced cost of the in vitro procedure, the possibility of results interpretation and the strict regulations concerning the use of animals for experimental purposes are the main reasons that support the implementation of such an in vitro test in the research labs.