Mobile Networking

We point out the different performance problems that need to be addressed when considering mobility in IP networks. We also define the reference architecture and present a framework to classify the different solutions for mobility management in IP networks. The performance of the major candidate micro-mobility solutions is evaluated for both real-time (UDP) and data (TCP) traffic through simulation and by means of an analytical model. Using these models we compare the performance of different mobility management schemes for different data and real-time services and the network resources that are needed for it. We point out the problems of TCP in wireless environments and review some proposed enhancements to TCP that aim at improving TCP performance. We make a detailed study of how some of micro-mobility protocols namely Cellular IP, Hawaii and Hierarchical Mobile IP affect the behavior of TCP and their interaction with the MAC layer. We investigate the impact of handoffs on TCP by means of simulation traces that show the evolution of segments and acknowledgments during handoffs.Publicad

Biblioteca de Ciències de la Salut de Catalunya: la coordinació i la cooperació entre biblioteques

Biblioteques de ciències de la salut; Xarxa de biblioteques; Pla estratègic; Marc estable de coordinació i cooperacióBibliotecas de ciencias de la salud; Red de bibliotecas; Plan estratégico; Marco estable de coordinación y cooperaciónHealth science libraries; Library network; Strategic plan; Stable framework for coordination and cooperationLa Biblioteca de Ciències de la Salut de Catalunya (BCS) es crea el 2014, dins de l’estructura del Departament de Salut de la Generalitat de Catalunya, amb l’objectiu de desenvolupar un sistema homogeni d’accés a la informació bibliogràfica i de proveir de serveis bibliogràfics als professionals del sector públic de salut català. En aquest context, es desenvolupa el Marc estable de coordinació i cooperació, format per les biblioteques del sector públic majoritari de salut, amb l’objectiu d’impulsar el canvi organitzatiu i la millora en la prestació de serveis bibliogràfics de forma col·laborativa

Self-heating in pulsed mode for signal quality improvement: application to carbon nanostructures-based sensors

Sensor signal instability and drift are still unresolved challenges in conductometric gas sensors. Here, the use of self-heating effect to operate a gas sensor in a pulsed temperature modulation mode (pulsed self-heating operation) is presented as an effective method to enhance signal stability and reduce consumption figures down to a few W. The sensor operation temperature was pulsed periodically between two levels, obtaining two different sensing states from one single device driven with self-heating, i.e. free of heater. The signal differences between both operating points correlated well with gas concentrations and displayed no drift. This methodology is exemplified with a thorough study of the response of carbon nanofibers to humidity. Specifically, after analyzing the influence of the pulse characteristics (i.e. temperature variation, pulse period and pulse duty cycle) on the sensor performance, thumb rules to select suitable pulsing conditions are provided. The methodology is successfully extended to other target gases, such as NO2 and NH3. Finally, its implementation in a real-time sensing system with low computational requirements is demonstrated and discussed in detail

Electrical properties of individual tin oxide nanowires contacted to platinum electrodes

A simple and useful experimental alternative to field-effect transistors for measuring electrical properties free electron concentration nd, electrical mobility , and conductivity in individual nanowires has been developed. A combined model involving thermionic emission and tunneling through interface states is proposed to describe the electrical conduction through the platinum-nanowire contacts, fabricated by focused ion beam techniques. Current-voltage I-V plots of single nanowires measured in both two- and four-probe configurations revealed high contact resistances and rectifying characteristics. The observed electrical behavior was modeled using an equivalent circuit constituted by a resistance placed between two back-to-back Schottky barriers, arising from the metal-semiconductor-metal M-S-M junctions. Temperature-dependent I-V measurements revealed effective Schottky barrier heights up to BE= 0.4 eV

Revisiting Colorimetric Gas Sensors: Compact, Versatile and Cost-Effective

We report on an inexpensive and very selective gas sensor implemented by simply combining colorimetric indicators casted on top of acetate-based transparent tape, with a commercial microchip adapted here to measure optical reflectance. This sensor can be easily reproduced (leading to quantitatively consistent results), refreshed and reconfigured to sense different target gases replacing only the colorimetric tape. The device may either work as sensor (CO2 and NH3) or dosimeter (Formaldehyde) depending on the targeted gas

Surfactant Protein A Forms Extensive Lattice-Like Structures on 1,2-Dipalmitoylphosphatidylcholine/Rough-Lipopolysaccharide- Mixed Monolayers

Due to the inhalation of airborne particles containing bacterial lipopolysaccharide (LPS), these molecules might incorporate into the 1,2-dipalmitoylphosphatidylcholine (DPPC)-rich monolayer and interact with surfactant protein A (SP-A), the major surfactant protein component involved in host defense. In this study, epifluorescence microscopy combined with a surface balance was used to examine the interaction of SP-A with mixed monolayers of DPPC/rough LPS (Re-LPS). Binary monolayers of Re-LPS plus DPPC showed negative deviations from ideal behavior of the mean areas in the films consistent with partial miscibility and attractive interaction between the lipids. This interaction resulted in rearrangement and reduction of the size of DPPC-rich solid domains in DPPC/Re-LPS monolayers. The adsorption of SP-A to these monolayers caused expansion in the lipid molecular areas. SP-A interacted strongly with Re-LPS and promoted the formation of DPPC-rich solid domains. Fluorescently labeled Texas red-SP-A accumulated at the fluid-solid boundary regions and formed networks of interconnected filaments in the fluid phase of DPPC/Re-LPS monolayers in a Ca2+-independent manner. These lattice-like structures were also observed when TR-SP-A interacted with lipid A monolayers. These novel results deepen our understanding of the specific interaction of SP-A with the lipid A moiety of bacterial LPS

Visible-Light-Driven Room Temperature NO2 Gas Sensor Based on Localized Surface Plasmon Resonance: The Case of Gold Nanoparticle Decorated Zinc Oxide Nanorods (ZnO NRs)

In this work, nitrogen dioxide (NO2) gas sensors based on zinc oxide nanorods (ZnO NRs) decorated with gold nanoparticles (Au NPs) working under visible-light illumination with different wavelengths at room temperature are presented. The contribution of localized surface plasmon resonant (LSPR) by Au NPs attached to the ZnO NRs is demonstrated. According to our results, the presence of LSPR not only extends the functionality of ZnO NRs towards longer wavelengths (green light) but also increases the response at shorter wavelengths (blue light) by providing new inter-band gap energetic states. Finally, the sensing mechanism based on LSPR Au NPs is proposed

Back-compatible Color QR Codes for colorimetric applications

Color correction techniques in digital photography often rely on the use of color correction charts, which require including this relatively large object in the field of view. We propose here to use QR Codes to pack these color charts in a compact form factor, in a fully compatible manner with conventional black and white QR Codes; this is, without losing any of their easy location, sampling and digital data storage features. First, we present an algorithm to build these new colored QR Codes that preserves the original QR Code functionality - much more than other coloring proposals based on the random substitution of black and white pixels by colors - that relies on the ability of the native CRC code to correct and counteract these alterations. Second, we demonstrate that, as a result, these QR Codes can allocate far many more colors than the conventional color correction charts, enabling much more accurate color correction schemes in a more convenient and usable format

Biblioteca Virtual del Sistema Sanitari Públic de Catalunya (BVSalut)

Biblioteca virtual; Recursos d’informació; Validació d’usuarisVirtual Library; Information resources; User authentication SystemBiblioteca virtual; Recursos de información; Validación de usuariosIntroducció La Biblioteca Virtual del Sistema Sanitari Públic de Catalunya (BVSalut) s’ha creat per ser el punt d’accés als recursos i als serveis bibliogràfics digitals de suport a la presa decisions per als professionals del sector públic majoritari de salut de forma equitativa i homogènia. Material i mètode Per desenvolupar el portal BVSalut es van analitzar quins serien els serveis que s’oferirien de forma virtual i quin seria el programari necessari que facilitaria la gestió, consulta i accés al portal, als serveis i als recursos bibliogràfics de forma segura per als professionals del sector públic majoritari de salut. Es va considerar que es posarien en funcionament els serveis virtuals següents: atenció a l’usuari i referència, alertes d’informació, informació especialitzada, obtenció de documents i préstec. Pel que fa al programari, es va considerar que era necessari disposar d’un gestor de continguts, un servei d’assistència a l’usuari (help desk), un programari per a la gestió del servei d’obtenció de documents, una eina de descoberta i una llista A/Z que facilités l’accés als recursos i evités els enllaços trencats. Al mateix temps, s’havia de garantir un sistema segur de validació d’usuaris que permetés als professionals de les diferents institucions poder accedir de forma segura als recursos electrònics que es posaven a la seva disposició. Concretament, es va desenvolupar un sistema de validació Single Sing‐On (SSO), que connectat a una LDAP (Lightweight Directory Access Protocol), amb la relació dels professionals i dels recursos que tenien accés, permetia que aquests professionals poguessin entrar als recursos bibliogràfics digitals de la BVSalut de forma simple i eficaç mitjançant el servidor proxy Ezproxy. Resultats S’ha donat accés als recursos bibliogràfics subvencionats per la Biblioteca de Ciències de la Salut de Catalunya a 79 entitats. Més de 40.000 professionals ja poden accedir a aquests als recursos electrònics i s’ha iniciat la redacció d’un pla estratègic, amb la col∙laboració de les biblioteques de les institucions del sector públic majoritari de salut, que facilitarà que aquests professionals també tinguin accés a serveis de suport bibliogràfic compartits. Conclusions El portal BVSalut ha permès establir un sistema homogeni d’accés als recursos i serveis bibliogràfics digitals. Progressivament s’aniran incrementant els recursos bibliogràfics i, amb la creació de la Xarxa de Biblioteques Especialitzades en Ciències de la Salut i l’aprovació de Pla estratègic, l’oferta de serveis virtuals compartits

Ex-Vivo and In-Vivo Assessment of Cyclamen europaeum Extract After Nasal Administration

Rhinosinusitis is a prevalent disorder with a severe impact on the health-related quality of life. Saponins of Cyclamen europaeum exert a clinically proven curative effect on rhinosinusitis symptoms when instilled into the nasal cavity, however, more extensive preclinical assessment is required to better characterize the efficacy of this botanical extract. This work evaluates the potential use of a natural freeze-dried extract of C. europaeum given as topical nasal administration. Permeation experiment on porcine nasal mucosa was performed with Franz diffusion cells. Experiments in rabbits were performed to test for any toxicological, hematological, biochemical or histological evidence of systemic action. No theoretical levels of saponins were found in the receptor chamber of Franz diffusion cells. Hematological data did not show significant differences between control and experimental animals (p > 0.05). Histological studies also showed that enhanced secretory activity in response to intranasal administration was not accompanied by any visible signs of injury. An examination of the brain, lungs, liver, kidneys, spleen, and gastrointestinal organs did not reveal any abnormality. The absence of mucosal permeation of saponins and negligible probability of C. europaeum saponins absorption in the course of a therapeutic application was demonstrated