The Tetragonal to Orthorhombic Structural Phase Transition in Multiband FeAs-based Superconductors

We report the temperature-dependent x-ray powder diffraction of the FeAs-based superconductors in the range between 300 and 95 K. In the case of NdOFeAs we have detected the structural phase transition from the tetragonal phase, with P4/nmm space group, to the orthorhombic phase, with Cmma space group, over a broad temperature range from 150 to 120 K, centered at T ₀∼137 K. This transition is reduced, by about ∼30 K, by the internal chemical pressure going from LaOFeAs to NdOFeAs. On the contrary, the superconducting critical temperature increases from 27 to 51 K going from LaOFeAs to NdOFeAs doped samples. The FeAs layers in all undoped “1111” and “122” systems suffer a tensile misfit strain. The tensile misfit strain is reduced in “1111” and in “122” samples and at optimum doping the misfit strain is close to zero. This result shows that the normal striped orthorhombic Cmma phase competes with the superconducting tetragonal phase. In the orthorhombic clusters the charges can move only along the stripes in the b direction and are localized by the magnetic interaction.     

Metabolic Syndrome and Male Fertility: Beyond Heart Consequences of a Complex Cardiometabolic Endocrinopathy

Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS.     

Order picking system design: the storage assignment and travel distance estimation (SA&TDE) joint method

Of all the warehouse activities, order picking is one of the most time-consuming and expensive. In order to improve the task, several researches have pointed out the need to consider jointly the layout of the warehouse, the storage assignment strategy and the routing policy to reduce travelled distances and picking time. This paper presents the storage assignment and travel distance estimation (SA&TDE) joint method, a new approach useful to design and evaluate a manual picker-to-parts picking system, focusing on goods allocation and distances estimation. Starting from a set of picking orders received in a certain time range, this approach allows to evaluate the combinations of product codes assigned to storage locations, aisles, sections or warehouse areas and to assess the most relevant ones, for the best location and warehouse layout, with the aim of ensuring optimal picking routes, through the application of the multinomial probability distribution. A case study is developed as well, in order to clarify the concept that underlies the SA&TDE joint method, and to show the validity and the flexibility of the approach, through the calculation of the saving at different levels of detail.     

Modeling Self-Rollable Elastomeric Films for Building Bioinspired Hierarchical 3D Structures

In this work, an innovative model is proposed as a design tool to predict both the inner and outer radii in rolled structures based on polydimethylsiloxane bilayers. The model represents an improvement of Timoshenko’s formula taking into account the friction arising from contacts between layers arising from rolling by more than one turn, hence broadening its application field towards materials based on elastomeric bilayers capable of large deformations. The fabricated structures were also provided with surface topographical features that would make them potentially usable in different application scenarios, including cell/tissue engineering ones. The bilayer design parameters were varied, such as the initial strain (from 20 to 60%) and the bilayer thickness (from 373 to 93 µm). The model matched experimental data on the inner and outer radii nicely, especially when a high friction condition was implemented in the model, particularly reducing the error below 2% for the outer diameter while varying the strain. The model outperformed the current literature, where self-penetration is not excluded, and a single value of the radius of spontaneous rolling is used to describe multiple rolls. A complex 3D bioinspired hierarchical elastomeric microstructure made of seven spirals arranged like a hexagon inscribed in a circumference, similar to typical biological architectures (e.g., myofibrils within a sarcolemma), was also developed. In this case also, the model effectively predicted the spirals’ features (error smaller than 18%), opening interesting application scenarios in the modeling and fabrication of bioinspired materials.     

Limited Accuracy of Pan-Trk Immunohistochemistry Screening for NTRK Rearrangements in Follicular-Derived Thyroid Carcinoma

Patients with advanced thyroid cancer harboring NTRK rearrangements can be treated with highly effective selective inhibitors. Immunohistochemistry (IHC) analysis, to detect Trk protein expression, represents an appealing screening strategy for NTRK rearrangements, but its efficacy has been poorly explored in thyroid cancer. The aim of this study is to investigate the diagnostic utility of Trk IHC in the identification of NTRK rearrangements. A series of 26 follicular-derived thyroid tumors, positive for NTRK rearrangements, and 28 NTRK fusion-negative controls were retrospectively analyzed by IHC using the pan-Trk monoclonal antibody (clone {"type":"entrez-protein","attrs":{"text":"EPR17341","term_id":"523383444","term_text":"EPR17341"}}EPR17341) on the Ventana system. Area under the curve (AUC), sensitivity and specificity were calculated by ROC analysis. Trk expression was detected in 25 samples, including 22 out of the 26 NTRK-rearranged (84.6%) and three out of 28 NTRK-negative samples (10.7%). Four out of twenty-six NTRK-rearranged thyroid tumors were negative for Trk expression (15.4%), all carrying the ETV6/NTRK3 fusion. The AUC, sensitivity and specificity were 0.87, 0.85 and 0.89, respectively. A screening based on IHC analysis showed limited sensitivity and specificity in the identification of NTRK-rearranged tumors. Since falsely negative results could preclude the administration of effective targeted drugs, alternative detection strategies should be considered for thyroid cancer.     

Empirical Evaluation of CASE Tools Usage at Nokia

We presentthe results of a research work targeted to understanding thedomains and consequences of CASE tools usage in Nokia. We aimto evaluate the importance of the various CASE tools features,as rated by our developers, and how well such features are implementedin currently available CASE tools. A structured questionnairewas sent to our most experienced developers and CASE users. Fromthis survey, it emerged that CASE tools support is reputed mostuseful for the following functions: graphical drawing, automaticdocumentation generation and storage of diagrams. The resultshint to a mismatch between the features required by the developersand those offered by CASE products. Further research is neededbefore more definite conclusions can be drawn.     

A straightforward design technique for narrowband multi‐stage low‐noise amplifiers with I/O conjugate match

Low‐noise amplifier (LNA) designers often struggle to simultaneously satisfy gain, noise, stability, and I/O matching requirements. In this article, a novel design technique, tailored for two‐stage low‐noise amplifiers, is presented. The proposed design method is completely deterministic and exploits inductive source degeneration to obtain a two‐stage LNA featuring perfect input and output match together with low noise figure (NF) and a pre‐determined gain, including stability analysis. A novel flowchart is provided together with the corresponding design chart that contains gain, matching, and stability information, therefore addressing all key figures‐of‐merit of a linear amplifier. The design chart is easily implementable in commercial Electronic Design Automation software, to aid designers in the difficult task of selecting the appropriate source degeneration inductor value. The noise performance, on the other hand, is the best possible since the matching networks are designed to provide the input of the two Field Effect Transistors with the optimum termination for noise. The design method is validated with two separate test vehicles operating respectively at Ka‐band (26.5‐31.5 GHz) and K‐band (20.0‐24.0 GHz). The realized Monolithic Microwave Integrated Circuits exhibit 18 dB gain for both versions, NF of 1.5 and 1.2 dB, respectively for the Ka‐band and K‐band version. Input and output matching are typically better than 12 and 15 dB.     

Exploring networks with traceroute-like probes: Theory and simulations

Mapping the Internet generally consists in sampling the network from a limited set of sources by using traceroute-like probes. This methodology, akin to the merging of different spanning trees to a set of destination, has been argued to introduce uncontrolled sampling biases that might produce statistical properties of the sampled graph which sharply differ from the original ones. In this paper, we explore these biases and provide a statistical analysis of their origin. We derive an analytical approximation for the probability of edge and vertex detection that exploits the role of the number of sources and targets and allows us to relate the global topological properties of the underlying network with the statistical accuracy of the sampled graph. In particular, we find that the edge and vertex detection probability depends on the betweenness centrality of each element. This allows us to show that shortest path routed sampling provides a better characterization of underlying graphs with broad distributions of connectivity. We complement the analytical discussion with a throughout numerical investigation of simulated mapping strategies in network models with different topologies. We show that sampled graphs provide a fair qualitative characterization of the statistical properties of the original networks in a fair range of different strategies and exploration parameters. Moreover, we characterize the level of redundancy and completeness of the exploration process as a function of the topological properties of the network. Finally, we study numerically how the fraction of vertices and edges discovered in the sampled graph depends on the particular deployements of probing sources. The results might hint the steps toward more efficient mapping strategies.     

Pressure‐Tunable Ambipolar Conduction and Hysteresis in Thin Palladium Diselenide Field Effect Transistors

Few‐layer palladium diselenide (PdSe₂) field effect transistors are studied under external stimuli such as electrical and optical fields, electron irradiation, and gas pressure. The ambipolar conduction and hysteresis are observed in the transfer curves of the as‐exfoliated and unprotected PdSe₂ material. The ambipolar conduction and its hysteretic behavior in the air and pure nitrogen environments are tuned. The prevailing p‐type transport observed at atmospheric pressure is reversibly turned into a dominant n‐type conduction by reducing the pressure, which can simultaneously suppress the hysteresis. The pressure control can be exploited to symmetrize and stabilize the transfer characteristics of the device as required in high‐performance logic circuits. The transistors are affected by trap states with characteristic times in the order of minutes. The channel conductance, dramatically reduced by the electron irradiation during scanning electron microscope imaging, is restored after an annealing of several minutes at room temperature. The work paves the way toward the exploitation of PdSe₂ in electronic devices by providing an experiment‐based and deep understanding of charge transport in PdSe₂ transistors subjected to electrical stress and other external agents.     

BETaaS: A Platform for Development and Execution of Machine-to-Machine Applications in the Internet of Things

Wireless Personal Communications - The integration of everyday objects into the Internet represents the foundation of the forthcoming Internet of Things (IoT). Smart objects will be the building...