223 research outputs found
High-Efficiency Gene Transfer into Adult Fish : a New Tool to Study Fin Regeneration
No full textZebrafish represents an excellent model to study the function of vertebrate genes (e.g., well-developed genetics, large number of mutants, and genomic sequencing in progress), inasmuch as we have tools to manipulate gene expression. Recent use of injected morpholinos in eggs provides a good method to " knockdown " gene expression in early development (Nasevicius and Ekker, 2000), and the "caged" RNA injected in eggs allows to overexpress a gene in a specific set of cells (Ando et al., 2001). However, a method to specifically modify gene expression in the juvenile or in the adult is still missing. Such a method would be a very powerful tool to understand gene function in differentiated tissues. We describe here an electroporation-based approach, which allows gene transfer in adult tissues. Its efficiency was assessed using a GFP (green fluorescent protein) dependent assay. We then used this method to disrupt the Fgf signalling pathway during the process of regeneration
A simple multiband printed bowtie antenna
No full textThis letter presents a new approach for the design of a multiresonant printed bowtie antenna. Several techniques were attempted to obtain one antenna which is operational in the 2, 3, and 5 GHz bands corresponding to many wireless applications. The idea of creating different slot configurations on different parts of a single antenna is the basic principle. A prototype of the final antenna design was fabricated tested and a good agreement was found between simulated and tested results. © 2008 IEEE.Balanis C. A., 2005, ANTENNA THEORY ANAL; Birch M, 2002, P SOC PHOTO-OPT INS, V4758, P573, DOI 10.1117-12.462195; Eldek AA, 2005, IEEE T ANTENN PROPAG, V53, P3067, DOI 10.1109-TAP.2005.851870; James J.R., 1989, IEE ELECTROMAGNETIC, V28; Karacolak T, 2006, IEEE ANTENN WIREL PR, V5, P446, DOI 10.1109-LAWP.2006.885013; Kiminami K, 2004, IEEE ANTENN WIREL PR, V3, P152, DOI 10.1109-LAWP.2004.832126; Lin YD, 1998, IEEE T ANTENN PROPAG, V46, P459; Nedil M., 2003, P CAN C EL COMP ENG, V3, P1433; Nishioka Y, 1999, IEEE T ANTENN PROPAG, V47, P970, DOI 10.1109-8.777119; TAWK Y, 2007, THESIS AM U BEIRUT L; Uduwawala D, 2004, IEEE T GEOSCI REMOTE, V42, P732, DOI 10.1109-TGRS.2003.819442; Yazdandoost K. Y., 2005, P IEEE WIRELESS COMM, P21282
Erratum: High-efficiency gene transfer into adult fish: A new tool to study fin regeneration (Genesis (January 2002) 32 (27-31))
No full textA new quadrifilar helix antenna for space communications
No full textThis paper presents a new quadrifilar helix antenna designed to deploy on a space craft for space communications. The quadrifilar helix is beryllium based and is deployed on top of a square ground plane. The ground plane is optimized to reduce back lobe radiation and achieve optimal gain and beam width. A trade off analysis is achieved and is discussed herein. The antenna dimensions and structure are studied to preserve operation in the S-band range while preserving stable radiation characteristics. © 2013 IEEE
A reconfigurable antenna with software controlled ground plane
No full textThis paper discusses an antenna design that achieves tuning of its frequency response by changing the height and angular position of its ground plane. The antenna is composed of a simple patch and three ground planes. Two ground planes are fixed while a third part moves and tilts based on the user's demand. The antenna's moving ground plane is controlled by an arduino board and two linear actuators. The antenna is simulated and measured. Good analogy is found between measured and simulated data. © 2013 IEEE
A low-cost microstrip antenna for 3G-WLAN-WiMAX and UWB applications
No full textThis paper presents a low-cost ultra-wideband microstrip antenna for wireless communications. Printed on a 40×50×1.83 mm3 Isola Gigaver 210 substrate, the antenna features a microstrip feed line with two 45° bends and a tapered section for size reduction and matching, respectively. The ground plane is partial and comprises a rectangular part and a trapezoidal part. The patch is a half ellipse, where the cut is made along the minor axis. Several slots are incorporated into the patch. The placement and sizes of the slots are assisted by the knowledge of fractal geometries . The return loss, input impedance, gain, efficiency and radiation characteristics of the antenna are presented. It is shown that the antenna can operate in the bands used for UMTS, WLAN, WiMAX, and UWB applications. © 2009 IEEE.*AG TECHN, ADS MOM 2006; Al-Husseini M., 2008, 2008 INT WIR COMM MO; ALHUSSEINI M, 2009, 26 NAT RAD SCI C NRS; Balanis C. A., 2005, ANTENNA THEORY ANAL; El-Khamy S. E., 2004, 21 NAT RAD SCI C NRS, P1; Kumar G., 2003, BROADBAND MICROSTRIP; Low ZN, 2005, IEEE ANTENN WIREL PR, V4, P237, DOI 10.1109-LAWP.2005.852577; Werner DH, 2003, IEEE ANTENN PROPAG M, V45, P38, DOI 10.1109-MAP.2003.1189650; Zhang JP, 2008, IEEE T ANTENN PROPAG, V56, P241, DOI 10.1109-TAP.2007.91316510
Frequency-tunable and pattern diversity antennas for cognitive radio applications
No full textFrequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR-) based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein. © 2014 A. H. Ramadan et al.Acampora A., 2010, P IEEE INT MICR WORK, P1; Al-Husseini M, 2011, IEEE ANTENNAS PROP, P2212; [Anonymous], SMV1405 SMV1419 HYP; Carey-Smith B. E., 2005, EURASIP Journal on Wireless Communications and Networking, V2005, DOI 10.1155-WCN.2005.354; Hong JS, 1997, IEEE T MICROW THEORY, V45, P2358; Lourandakis E, 2012, IEEE MICROW MAG, V13, P111, DOI 10.1109-MMM.2011.2173987; Marques R, 2008, WILEY MICRO, P1; Perruisseau-Carrier J., 2010, P R SOC B, P1; Razavi B, 2009, IEEE CUST INTEGR CIR, P391; Yucek T, 2009, IEEE COMMUN SURV TUT, V11, P116, DOI 10.1109-SURV.2009.0901091
Radiation and frequency reconfiguration using tilted printed monopoles
No full textThis paper presents a reconfigurable printed two arms monopole antenna structure. The proposed antenna is able to change either its operating frequency or radiation pattern based on the activation of the integrated PIN diode switches. The purpose of the switches is to connect one of the two monopole arms or both to the antenna feeding line. A prototype antenna is simulated, built and tested. A good agreement is found between the simulated and measured data. © 2013 IEEE
Automatización de la recopilación de datos en el proceso de ventas de Wiwa tours mediante la integración del Crm Hubspot
No full textEste proyecto tiene como finalidad optimizar la recopilación de datos de los clientes que llegan a través de los distintos canales de recepción de la empresa tales como Whatsapp, Correo electrónico, Tawk-to, mediante la implementación de la plataforma HubSpot. Con esta herramienta, se busca agilizar los procesos del área de ventas, automatizar tareas manuales, mejorar la organización del trabajo, la satisfacción del cliente, la comunicación y facilitar el seguimiento de los mensajes.
Todo esto con el objetivo de reducir los tiempos operativos y permitir que el equipo enfoque sus esfuerzos en crear estrategias de marketing que atraigan nuevos clientes y fortalezcan la fidelización de los actuales
Tuning a cognitive radio antenna system with motion detection
No full textIn this paper we discuss a cognitive radio antenna system that possesses the ability to tune its operation based on sensing movements in its surrounding. The surrounding awareness ability is added by incorporating an Infra Red (IR) motion detector with the antenna system. This concept is tested on a varactor based reconfigurable filter cascaded with a cognitive radio antenna system. Once movement is detected, the IR sensor generates a voltage that can be varied to allow the tuning of the varactor and the tuning of the antenna operating frequency. The cognitive radio system is measured and analyzed for concept validation © 2013 EurAAP
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