Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice [Dataset]

6 pages. -- S1. Transversal electric field distribution for the SLR at 1.57 eV. -- S2. Simulated electric field and charge distributions for a threesome of slits. -- S3. Simulated electric field and charge distributions for the simplest local dark mode of the inverted honeycomb lattice. -- S4. Profiles of the EELS signal and the simulated electric field along the slits for the antiferroelectric dark modes. -- S5. Array of the magnetic dipoles over the structure used to simulate antiferroelectric dark modes.Plasmonic lattice nanostructures are of technological interest because of their capacity to manipulate light below the diffraction limit. Here, we present a detailed study of dark and bright modes in the visible and near-infrared energy regime of an inverted plasmonic honeycomb lattice by a combination of Au+ focused ion beam lithography with nanometric resolution, optical and electron spectroscopy, and finite-difference time-domain simulations. The lattice consists of slits carved in a gold thin film, exhibiting hotspots and a set of bright and dark modes. We proposed that some of the dark modes detected by electron energy-loss spectroscopy are caused by antiferroelectric arrangements of the slit polarizations with two times the size of the hexagonal unit cell. The plasmonic resonances take place within the 0.5–2 eV energy range, indicating that they could be suitable for a synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.Peer reviewe

How to drive robotic microscope on TMA slide to measure biomarkers expression: an ordering algorithm

In TMA data management a crucial step is the correct recognition of each core section position in the array, i.e. the right assignment to each core of proper row and column numbers for reliable further data analysis. The available commercial systems support manual or semi-automatic problem solutions. In this talk we present a new approach, based on a ad hoc developed mathematical algorithm, which automatically locates each core section following the right order, allowing a robotic microscope1 to acquire a correct ordered sequence of single core images at high magnification. The algorithm inputs are the digital image of the complete slide and some parameters chosen during block array preparation; the outputs are the ordered list of the coordinates of the core sections centres and an index associated to each spot, representing its dimension and local environment anomalies. Together with algorithm description we present the first results of algorithm accuracy tests and assessment of working constrains. The tool described here is part of an integrated TMA management system, consisting in an automatic image acquisition environment and a web-based multi-centre data collection system2,3. Single core section images at medium and high magnification are processed by a tool we are developing to provide a quantitative evaluation of the expression of some biomarkers on breast tissue samples in an automatic way. In this talk we present some results of applying this image processing and analysis procedure to a nuclear and a cytoplasmatic marker. [1] Demichelis F, Barbareschi M et. al `The Virtual Case. A new method to completely digitise cytological and histological slides`, Virchow Arch 441:159-164, 2002 [2] Dell’Anna R, Demichelis F, Barbareschi M, Doglioni C. “Tissue Microarray Data System”, Sept. 2002 Tech.Rep. ITC, #0209-09. [3] https://bioinfo.itc.it/TM

Web based Tissue Microarray Management System

Enormous data sets and information are involved in TMA based studies; well structured data management system are mandatory. The incremental need to share data among different institutions and multicentric studies suggests the implementation of web based systems and the definition of a standard to be applied in exchanging data (see http://www.pathinfo.com/jjb/tmadtd2.htm). Data concerning with TMA based studies are biological/genetic, clinical and morphologic. Digital images of entire array slides and of single core sections are necessary for eventually automated scoring and for exhaustive storage. Relational database addresses the requirements to organize in an efficient manner all the data. In our system insertion, updating and retrieval of data are provided through web pages (Active Server Pages) constructed to satisfy different data entry types and peculiar work phases. Different views are designed to map the workflows of different workphases. The intrinsic difficulty of TMA samples analysis by conventional microscope (hundreds of tumours spots on the same slide) suggests the storage of digital images of single core section, uniquely related to the tumour identifier, and of overview images of entire slides. Robotic microscopy is well suitable for this kind of issues. Digital images of core sections enable the pathologists to easily compare the immunostainings tumour samples on computer screen through a microscope simulator. Having a TMA management system the problem shifts from data generation to data-mining and deriving information from such material (Journal of Pathology, 2001 195:1-2). Patterns in TMA biological data of gene expression have to be evaluated. Correlations of expression with clinical and follow up data are of main interest for prognosis and therapeutic investigation. To assess the screening approach to the analysis of potential markers, classical statistics as uni-multivariate analysis together with supervised and unsupervised cluster analysis will be utilized. This work has been granted by the Ministry of Public Health of Italian Governmen

Hierarchical thermoplastic rippled nanostructures regulate Schwann Cell adhesion, morphology and spatial organization

Periodic ripples are a variety of anisotropic nanostructures that can be realized by ion beam irradiation on a wide class of solid surfaces. Only few authors have investigated these surfaces for tuning the response of biological systems, probably because it is challenging to directly produce them in materials that well sustain long-term cellular cultures. Here, hierarchical rippled nanotopographies with lateral periodicity of ∽300 nm are produced from a gold-irradiated germanium mold in polyethylene terephthalate (PET), a biocompatible polymer approved by the US Food and Drug Administration for clinical applications, by a novel three-steps embossing process. The effects of nano-ripples on Schwann Cells (SCs) are studied in view of their possible use for nerve-repair applications. Data demonstrate that nano-ripples can enhance short-term SC adhesion and proliferation (3-24h from seeding), drive their actin cytoskeleton spatial organization and sustain long-term cell growth. Notably, SCs orient perpendicularly with respect to the nanopattern lines. These results provide information about the possible use of hierarchical nano-rippled elements for nerve-regeneration protocols

Use of ATR-FTIR Microspectroscopy to Monitor Autolysis of Saccharomyces cerevisiae Cells in a Base Wine

In this study, we evaluated the potentialities of ATR-FTIR microspectroscopy coupled to PCA in monitoring the major biochemical changes that occur during the autolysis of yeasts used for sparkling wine production. For this purpose, mid-infrared measurements were made on cells of the model strain Saccharomyces cerevisiae EC1118 in the course of autolysis induced at 30 °C for five days in a model and in a base wine. By relating principal component loadings to the corresponding absorption bands, it was shown that they well describe compositional modifications induced by autolytic process on yeast cells, such as partial hydrolysis of proteins, increase of peptides, free nucleotides, lipids, mannans, and β-1,3 glucans. The corresponding score−score plots allowed us to monitor the different kinetics and to distinguish among faster, intermediate, and slower processes. ATR-FTIR microspectroscopy coupled with PCA is proposed as a sensitive method that can provide useful information to select efficient yeast strains, capable of accelerated autolysis, to be used in the second fermentation and aging of sparkling wines

Combining Supervised and Unsupervised Methods to Support Early Diagnosis of Hepatocellular Carcinoma

The early diagnosis of Hepatocellular Carcinoma (HCC) is extremely important for effective treatment and improvements in diagnosis are indispensable, particularly concerning the differentiation between “early” HCC and non neoplastic nodules. In this paper, we reconsidered the results obtained previously and compared them with the results of an unsupervised method to achieve a deep knowledge on uncertain lesions. This analysis agreed with the predictions on DNs obtained by the supervised system, providing pathologists with reliable information to support their diagnostic proces

Nanofabrication of self-organized periodic ripples by ion beam sputtering

Ion beam sputtering can induce the formation of regular self-assembled surface nanostructures on different materials. Several experimental variables, such as the ion energy, the ion incidence angle, the ion fluence, together with the sample surface properties and temperature, have been proven to control in a complex and not completely codified manner the formation of periodically arranged dot, hole or ripple nanopatterns. In this work, we have studied how to apply ion beam sputtering to induce periodic ripples of specific aspect ratio on silicon surfaces, namely ripple height a of about 10 nm and period λ ≤ 50 nm, since these topographies can be appealing for technological applications. Silicon surfaceswere irradiated with increasingO+and Xe+ion fluences at fixed ion energy and incidence angle. We have verified that some combinations of the chosen parameter values produced the desired structures. The obtained results also indicate thatwith a further refinement of those parameter values a better control of the aspect ratio of the obtained ripples is possible. Therefore, this work is a contribution to the final aim of exploiting ion beam sputtering as a fast, cost-effective and single-step method to fabricate well-controlled patterns over large surface areas at length scales beyond those of both standard and e-beam lithography