Gas leak-detection system

Data monitoring of gas leakage in satellites and spacecraft is facilitated by adding gaseous radioisotopes to cold compressed gas and mounting a detector in the thrust nozzle

MIDAS: Automated Approach to Design Microwave Integrated Inductors and Transformers on Silicon

The design of modern radiofrequency integrated circuits on silicon operating at microwave and millimeter-waves requires the integration of several spiral inductors and transformers that are not commonly available in the process design-kits of the technologies. In this work we present an auxiliary CAD tool for Microwave Inductor (and transformer) Design Automation on Silicon (MIDAS) that exploits commercial simulators and allows the implementation of an automatic design flow, including three-dimensional layout editing and electromagnetic simulations. In detail, MIDAS allows the designer to derive a preliminary sizing of the inductor (transformer) on the bases of the design entries (specifications). It draws the inductor (transformer) layers for the specific process design kit, including vias and underpasses, with or without patterned ground shield, and launches the electromagnetic simulations, achieving effective design automation with respect to the traditional design flow for RFICs. With the present software suite the complete design time is reduced significantly (typically 1 hour on a PC based on Intel® Pentium® Dual 1.80GHz CPU with 2-GB RAM). Afterwards both the device equivalent circuit and the layout are ready to be imported in the Cadence environment

Quantum field corrections to the equation of state of freely streaming matter in the Friedman-Lemaitre-Robertson-Walker space-time

We calculate the energy density and pressure of a scalar field after its decoupling from a thermal bath in the spatially flat Friedman-Lema\^itre-Robertson-Walker space-time, within the framework of quantum statistical mechanics. By using the density operator determined by the condition of local thermodynamic equilibrium, we calculate the mean value of the stress-energy tensor of a real scalar field by subtracting the vacuum expectation value at the time of the decoupling. The obtained expressions of energy density and pressure involve corrections with respect to the classical free-streaming solution of the relativistic Boltzmann equation, which may become relevant even at long times.Comment: 18 pages, 1 figure; finally published versio

Negative pressure as a quantum effect in free-streaming in the cosmological background

We present a study of energy density and pressure of a free real scalar quantum field after its decoupling from a thermal bath in the spatially flat Friedman-Lemaitre-Robertson-Walker space-time by solving the Klein-Gordon equation both analytically and numerically for different predetermined scale factor functions $a(t)$. The energy density and pressure, defined by subtracting the vacuum expectation values at the decoupling time, feature corrections with respect to the classical free-streaming solution of the relativistic Boltzmann equation. We show that if the expansion rate is comparable or larger than $mc^2/\hbar$ or $KT_0/\hbar$ where $m$ is the mass and $T_0$ the decoupling temperature, both energy density and pressure gets strong quantum corrections which substantially modify their classical dependence on the scale factor $a(t)$ and drive pressure to large negative values. For a minimally coupled field with a very low mass in an expanding de Sitter universe quantum corrections are dominant driving pressure and energy density to become asymptotically constant with an equation of state $p/\varepsilon \simeq -1$, thereby mimicking a cosmological constant. For a minimally coupled massless field, quantum corrections are asymptotically dominant for any accelerated expansion.Comment: 28 pages, 15 figure

Characterization of CMOS Spiral Inductors

In this work "full-wave" simulations of integrated inductors are presented and compared with measurements of fabricated CMOS chips. The good agreement between measurements and simulations demonstrates the accuracy of the tool, which is, hence, a cheaper alternative to experimental characterization. Furthermore, the proposed approach may give precious hints for performance improvements, by making internal device fields and currents available for the VLSI designer and providing compact, most effective, equivalent models

Thromboembolic events in patients treated with anti-angiogenic drugs

Induction of neo-angiogenesis is a fundamental step in many pathological conditions. The therapeutic value of inhibiting angiogenesis is an interesting area of research in oncology, with vascular endothelial growth factor (VEGF) being the most suitable anti-angiogenic target. In the last decade a number of anti-VEGF drugs have demonstrated, especially in combination with standard chemotherapy, clinical efficacy in the treatment of different solid tumor types. As data from clinical trials on anti-VEGF drugs are becoming available, it is increasingly recognized that VEGF, in addition to being a permeability, proliferation, and migration factor, is also a maintenance and protection factor for endothelial cells, being capable of regulating multiple biological functions, i.e. the production of vasoactive mediators and the expression of components of the thrombolytic and coagulation pathways. Consequently, the disturbance of vascular homeostasis by blocking VEGF may lead to endothelial dysfunction and adverse vascular effects, such as venous and arterial thromboembolic events. In preclinical models angiogenesis and the increased expression of VEGF has been associated to altered expression of proinflammatory genes. These genes may be regulated in a biphasic manner, and it is possible that anti-VEGF therapy may disrupt a negative feedback loop that leads to potential in situ thrombus formation. Accordingly, combination treatment with bevacizumab and chemotherapy, compared with chemotherapy alone, was recently associated with an increased risk of thromboembolism. The present review considers the biological mechanisms and clinical impact of thromboembolic complications during anti-angiogenic treatments in cancer patients

Superconductor Microwave Kinetic Inductance Detectors: System Model of the Readout Electronics

This paper deals with the readout electronics needed by superconductor Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are typically implemented in the form of cryogenic-cooled high quality factor microwave resonator. The natural frequency of these resonators changes as a millimeter or sub-millimeter wave radiation impinges on the resonator itself. A quantitative system model of the readout electronics (very similar to that of a vector network analyzer) has been implemented under ADS environment and tested by several simulation experiments. The developed model is a tool to further optimize the readout electronic and to design the frequency allocation of parallel-connected MKIDs resonators. The applications of MKIDs will be in microwave and millimeter-wave radiometric imaging as well as in radio-astronomy focal plane arrays

Evidenze della rapida variazione di profondità della Moho, in corrispondenza dell'area di Città di Castello (Appennino Settentrionale), dall'analisi di funzioni ricevitore

In questo studio è stata sfruttata l’opportunità di poter analizzare dati provenienti da una densa rete sismica locale temporanea costituita da 30 stazioni a tre componenti, installata nell’ambito di un progetto del Gruppo Nazionale per la Difesa dei Terremoti (GNDT) nel periodo compreso fra l’Ottobre 2000-Maggio 2001, in un’area che si estende per circa 2800 km2 a circa 43° N in Appennino Settentrionale (Piccinini et al., 2003), al fine di ottenere un dettagliato andamento della topografia della Moho, in una zona così complessa, attraverso un’analisi delle Funzioni Ricevitore (Langston, 1979), definendo la struttura di velocità delle onde di taglio (S) al di sotto di ciascuna delle 28 stazioni sismiche. Sono stati analizzati circa 400 eventi telesismici registrati da 28 stazioni con valori di magnitudo M>5 e distanza epicentrale Δ compresi fra 25°-100°. Per il calcolo delle RFs è stato utilizzato il metodo sviluppato da Di Bona (1998), tale metodo consente di ottenere una stima della varianza, permettendo l’utilizzo di forme d’onda generate da eventi di bassa magnitudo (aventi valori di varianza accettabili), con un conseguente ampliamento del data-set. Modellando ampiezze e tempi di arrivo delle fasi Ps in funzione dell’azimuth di provenienza (BAZ) e della relativa distanza epicentrale (Δ), si possono ricostruire le geometrie delle superfici di discontinuità al di sotto delle stazioni sismiche. La fase di modellazione è stata condotta attraverso l’applicazione dell’algoritmo di inversione “neighbourhood” di Sambridge (1999) mediante un approccio monodimensionale. Questo metodo consente di campionare in maniera estensiva lo spazio dei parametri (profondità delle varie interfacce e valori di velocità negli strati compresi fra le interfacce), concentrando la ricerca in quelle regioni dello spazio multiparametrico dove i modelli di velocità trovati hanno un miglior misfit rispetto al dato (la RF) reale. Tale fase di modellazione ha consentito di ricostruire i modelli di velocità delle onde S (Vs) al di sotto di ciascuna stazione. L’analisi comparata dei modelli di velocità delle onde S (Vs) così ottenuti, per ogni singola stazione, mette in luce la natura fortemente eterogenea della porzione più superficiale della crosta dell’area in studio. Nonostante la complessità delle RFs calcolate che si riflette sulla eterogeneità della porzione più superficiale dei profili di Vs ottenuti, è stata individuata con buona continuità l’andamento di una superficie di discontinuità sismica da noi interpretata come transizione crosta-mantello superiore o Moho

Biological effects of a software-controlled voltage pulse generator (PhyBack PBK-2C) on the release of vascular endothelial growth factor (VEGF)

Electrical stimulation (ES) may induce vascular permeability and physiological angiogenesis. ES of rat muscles significantly increases the microvessel density and vascular endothelial growth factor (VEGF) protein levels. Thus, a pilot study was designed to analyze the effects of low-voltage electric impulses on VEGF levels in patients with dystrophic ulcers

Interleukin-2 inhalation therapy in renal cell cancer: a case report and review of the literature

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. One third of RCC presents metastatic disease at the time of diagnosis, usually leading to a fatal outcome. Small response rates were seen with most cytotoxic agents including gemcitabine and vinorelbine, whereas systemic therapy with high doses of interleukin 2 (IL-2) has been shown to provide durable complete remissions. However, in consideration of its severe toxicity, IL-2 immunotherapy is restricted to selected patients. Aerosol IL-2 has been introduced as an alternative therapy in cancer patients. However, only very few data are available on its use in patients with pulmonary metastatic RCC. This paper briefly summarizes current clinical experience with the use of inhaled IL-2 therapy, either as a single therapy or in combination with other treatments. In addition, we report on a male patient with pulmonary metastasized RCC who achieved a durable complete response to combined gemcitabine/vinorelbine and interleukin-2 inhalation therapy