"Hepatoid" gastric tumor]

In this study the Authors describe two cases of hepatoid adenocarcinoma of the stomach: one is characterized by the presence of alpha-fetoprotein (AFP) high levels of the serum both pre and post-operating and by the very positive response to the adjuvant chemotherapy (how the return to the normality of such values demonstrates). The other is instead characterized by the presence of post operating hepatic metastasis, event which is very frequent in this kind of neoplasm, but presents many problems concerning the differential histological diagnostics with the primitive hepatocarcinoma (problems which are nowadays not completely solved). Moreover the Authors relate to this study the revision of the international literature of the main characteristics and of prognosis of this particular and rare neoplasm.     

Use of the ITS rDNA for elucidation of some life-cycles of Mesometridae (Trematoda, Digenea)

Identification of larval stages is crucial for elucidating the life-cycles of various Digenea. However, in many digenean species, the larvae lack distinctive morphological features and it is impossible to establish the affiliation between the larval and adult stages by using morphological criteria. Molecular methods, based on DNA sequencing or PCR-restriction fragment length polymorphism analysis, can offer a new tool for larval-stage identification. In this study, the sequences of internal transcribed spacer of the ribosomal DNA were used to identify the cercariae of three out of five species of the family Mesometridae (Centroderma spinosissima, Elstia stossichianum and Wardula capitellata). The three species differ from one another by number of repeats in the region of internal transcribed spacer 1. The phylogeny of Mesometridae was inferred from their internal transcribed spacer ribosomal DNA sequences. The PCR-linked restriction fragment length polymorphism approach was developed for future life-cycle and ecological studies of this family.     

Momentum-space reservoir for enhancement of intersubbandsecond-harmonic generation

We analyze fundamental limits to the second-harmonic conversion efficiency attainable from semiconductor intersubband devices employing asymmetric stepped and double quantum wells. The coupled propagation equations have been solved numerically, accounting for saturation, absorption, and optical heating. It is found that the key figure of merit is the conversion efficiency at the onset of saturation, which has a remarkably simple form depending only on the ratio of broadening time to intersubband relaxation time and on another ratio involving the optical matrix elements. We show that since there are fundamental limits to the values of these ratios, it is unlikely that conversion efficiencies exceeding ≈10% can be attained in devices of the type considered in the previous literature, and for surface incidence even efficiencies approaching that value will require impractically-thick active regions. While detuning from the double resonance condition is often advantageous, net improvements to the optimum performance are relatively modest. However, these limitations ran be transcended by placing the subband system in contact with an optically-inactive momentum-space reservoir, which shunts the intersubband relaxation and delays saturation by refilling the depleted subband states with electrons from the reservoir. We propose a specific device based on Γ-valley active states and L-valley reservoir states in InAs-GaSb-AlSb asymmetric double quantum wells, whose energy levels and optical matrix elements are modeled using an 8-band finite-element calculation. It is predicted that a conversion efficiency of 20% can be achieved in an active-layer thickness of less than 10 μm     

Monocular Template-based Reconstruction of Inextensible Surfaces

We present a monocular 3D reconstruction algorithm for inextensible deformable surfaces. It uses point correspondences between a single image of the deformed surface taken by a camera with known intrinsic parameters and a template. The main assumption we make is that the surface shape as seen in the template is known. Since the surface is inextensible, its deformations are isometric to the template. We exploit the distance preservation constraints to recover the 3D surface shape as seen in the image. Though the distance preservation constraints have already been investigated in the literature, we propose a new way to handle them. Spatial smoothness priors are easily incorporated, as well as temporal smoothness priors in the case of reconstruction from a video. The reconstruction can be used for 3D augmented reality purposes thanks to a fast implementation. We report results on synthetic and real data. Some of them are compared to stereo-based 3D reconstructions to demonstrate the efficiency of our method.     

The design of photovoltaic plants: An optimization procedure

In this paper we discuss a simple analytical method which allows one to predict the fraction of the load covered by a photovoltaic plant as a function of the dimensions of its components (i.e. area of the photovoltaic array and battery storage capacity), of the meteorological parameters and of the user's load.We then use this method to perform an economic analysis for standalone plants and for fuel-assisted plants.     

Groupwise geometric and photometric direct image registration

Image registration consists in estimating geometric and photometric transformations that align two images as best as possible. The direct approach consists in minimizing the discrepancy in the intensity or color of the pixels. The inverse compositional algorithm has been recently proposed by Baker et al. for the direct estimation of groupwise geometric transformations. It is efficient in that it performs several computationally expensive calculations at a pre-computation phase. Photometric transformations act on the value of the pixels. They account for effects such as lighting change. Jointly estimating geometric and photometric transformations is thus important for many tasks such as image mosaicing. We propose an algorithm to jointly estimate groupwise geometric and photometric transformations while preserving the efficient pre-computation based design of the original inverse compositional algorithm. It is called the dual inverse compositional algorithm. It uses different approximations than the simultaneous inverse compositional algorithm and handles groupwise geometric and global photometric transformations. Its name stems from the fact that it uses an inverse compositional update rule for both the geometric and the photometric transformations. We demonstrate the proposed algorithm and compare it to previous ones on simulated and real data. This shows clear improvements in computational efficiency and in terms of convergence.     

Potential natural polymer-based nanofibres for the development of facemasks in countering viral outbreaks

The global coronavirus disease 2019 (COVID-19) pandemic has rapidly increased the demand for facemasks as a measure to reduce the rapid spread of the pathogen. Throughout the pandemic, some countries such as Italy had a monthly demand of ca. 90 million facemasks. Domestic mask manufacturers are capable of manufacturing 8 million masks each week, although the demand was 40 million per week during March 2020. This dramatic increase has contributed to a spike in the generation of facemask waste. Facemasks are often manufactured with synthetic materials that are non-biodegradable, and their increased usage and improper disposal are raising environmental concerns. Consequently, there is a strong interest for developing biodegradable facemasks made with for example, renewable nanofibres. A range of natural polymer-based nanofibres has been studied for their potential to be used in air filter applications. This review article examines potential natural polymer-based nanofibres along with their filtration and antimicrobial capabilities for developing biodegradable facemask that will promote a cleaner production.     

Numerical and experimental study of guided waves for detection of defects in the rail head

This paper gives insight to the ultrasonic wave propagation in arbitrary cross-section waveguides such as rails, with application to ultrasonic inspection. Due to the geometrical complexity of the rail cross-section, the analytical solution to the wave propagation in the rail is not feasible. A Semi Analytical Finite Element method is described as an alternative yet still robust approach to get the solution of the problem. The free-vibration solution and the forced solution to a laser excitation of the rail head are shown up to a frequency of 500 kHz. The effects of different loading patterns are discussed, and experimental results are provided. The analysis allows for the identification of certain wave modes potentially sensitive to specific types of rail head defects.