Effect of nano-scale morphology on micro-channel wall surface and electrical characterization in lead silicate glass micro-channel plate

Science.gov (United States)

Cai, Hua; Li, Fangjun; Xu, Yanglei; Bo, Tiezhu; Zhou, Dongzhan; Lian, Jiao; Li, Qing; Cao, Zhenbo; Xu, Tao; Wang, Caili; Liu, Hui; Li, Guoen; Jia, Jinsheng

2017-10-01

Micro-channel plate (MCP) is a two dimensional arrays of microscopic channel charge particle multiplier. Silicate composition and hydrogen reduction are keys to determine surface morphology of micro-channel wall in MCP. In this paper, lead silicate glass micro-channel plates in two different cesium contents (0at%, 0.5at%) and two different hydrogen reduction temperatures (400°C,450°C) were present. The nano-scale morphology, elements content and chemical states of microporous wall surface treated under different alkaline compositions and reduction conditions was investigated by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), respectively. Meanwhile, the electrical characterizations of MCP, including the bulk resistance, electron gain and the density of dark current, were measured in a Vacuum Photoelectron Imaging Test Facility (VPIT).The results indicated that the granular phase occurred on the surface of microporous wall and diffuses in bulk glass is an aggregate of Pb atom derived from the reduction of Pb2+. In micro-channel plate, the electron gain and bulk resistance were mainly correlated to particle size and distribution, the density of dark current (DDC) went up with the increasing root-mean-square roughness (RMS) on the microporous wall surface. Adding cesiums improved the size of Pb atomic aggregation, lowered the relative concentration of [Pb] reduced from Pb2+ and decreased the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a less dark current. Increasing hydrogen reduction temperature also improved the size of Pb atomic aggregation, but enhanced the relative concentration of [Pb] and enlarged the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a larger dark current. The reasons for the difference of electrical characteristics were discussed.

Characterization of Morphology using MAMA Software

Energy Technology Data Exchange (ETDEWEB)

Gravelle, Julie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-02

The MAMA (Morphological Analysis for Material Attribution) software was developed at the Los Alamos National Laboratory funded through the National Technical Nuclear Forensics Center in the Department of Homeland Security. The software allows images to be analysed and quantified. The largest project I worked on was to quantify images of plutonium oxides and ammonium diuranates prepared by the group with the software and provide analyses on the particles of each sample. Images were quantified through MAMA, with a color analysis, a lexicon description and powder x-ray diffraction. Through this we were able to visually see a difference between some of the syntheses. An additional project was to revise the manual for MAMA to help streamline training and provide useful tips to users to more quickly become acclimated to using the software. The third project investigated expanding the scope of MAMA and finding a statistically relevant baseline for the particulates through the analysis of maps in the software and using known measurements to compare the error associated with the software. During this internship, I worked on several different projects dealing with the MAMA software. The revision of the usermanual for the MAMA software was the first project I was able to work and collaborate on. I first learned how to use the software by getting instruction from a skilled user at the laboratory, Dan Schwartz, and by using the existing user manual and examples. After becoming accustomed to the program, I started to go over the manual to correct and change items that were not as useful or descriptive as they could have been. I also added in tips that I learned as I explored the software. The updated manual was also worked on by several others who have been developing the program. The goal of these revisions was to ensure the most concise and simple directions to the software were available to future users. By incorporating tricks and shortcuts that I discovered and picked up

Pressure Drop and Catalytic Dehydrogenation of NaBH{sub 4} Solution Across Pin Fin Structures in a Microchannel Reactor

Energy Technology Data Exchange (ETDEWEB)

Jung, Ki Moon [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of); Choi, Seok Hyun [Key Valve Technologies Ltd., Siheung (Korea, Republic of); Lee, Hee Joon [Kookmin Univ., Seoul (Korea, Republic of)

2017-06-15

Dehydrogenation from the hydrolysis of a sodium borohydride (NaBH{sub 4}) solution has been of interest owing to its high theoretical hydrogen storage capacity (10.8 wt.%) and potentially safe operation. An experimental study has been performed on the catalytic reaction rate and pressure drop of a NaBH4 solution over both a single microchannel with a hydraulic diameter of 300 μm and a staggered array of micro pin fins in the microchannel with hydraulic diameter of 50 μm. The catalytic reaction rates and pressure drops were obtained under Reynolds numbers from 1 to 60 and solution concentrations from 5 to 20 wt.%. Moreover, reacting flows were visualized using a high-speed camera with a macro zoom lens. As a result, both the amount of hydrogenation and pressure drop are 2.45 times and 1.5 times larger in a pin fin microchannel array than in a single microchannel, respectively.

Method to improve near-field nonlinearity of a high-power diode laser array on a microchannel cooler

Science.gov (United States)

Zhang, Hongyou; Jia, Yangtao; Cai, Wanshao; Tao, Chunhua; Zah, Chung-en; Liu, Xingsheng

2018-03-01

Due to thermal stress, each emitter in a semiconductor laser bar or array is vertically displaced along the p-n junction; the result is that each emitter is not in a line, called near-field nonlinearity. Near-field nonlinearity along a laser bar (also known as "SMILE" effect) degrades the laser beam brightness, which causes an adverse effect on optical coupling and beam shaping. A large SMILE value causes a large divergence angle after collimation and a wider line after collimation and focusing. We simulate the factors affecting the SMILE value of a high-power diode laser array on a microchannel cooler (MCC). According to the simulation results, we have fabricated a series of laser bars bonded on MCCs with lower SMILE value. After simulation and experiment analysis, we found the key factor to affect SMILE is the deformation of the thin MCC because of the distribution of strain and stress in it. We also decreased the SMILE value of 1-cm-wide full bar AuSn bonded on MCCs from 12 to 1 μm by balancing force on MCC to minimize the deformation.

Induced- and alternating-current electro-osmotic control of the diffusion layer growth in a microchannel-membrane interface device

Science.gov (United States)

Park, Sinwook; Yossifon, Gilad

2014-11-01

The passage of an electric current through an ionic permselective medium under an applied electric field is characterized by the formation of ionic concentration gradients, which result in regions of depleted and enriched ionic concentration at opposite ends of the medium. Induced-current electro-osmosis (ICEO) and alternating-current-electro-osmosis (ACEO) are shown to control the growth of the diffusion layer (DL) which, in turn, controls the diffusion limited ion transport through the microchannel-membrane system. We fabricated and tested devices made of a Nafion membrane connecting two opposite PDMS microchannels. An interdigitated electrode array was embedded within the microchannel with various distances from the microchannel-membrane interface. The induced ICEO (floating electrodes) / ACEO (active electrodes) vortices formed at the electrode array stir the fluid and thereby suppress the growth of the DL. The intensity of the ACEO vortices is controlled by either varying the voltage amplitude or the frequency, each having its own unique effect. Enhancement of the limiting current by on-demand control of the diffusion length is of importance in on-chip electro-dialysis, desalination and preconcentration of analytes.

Salud : Cáncer de mama

OpenAIRE

1986-01-01

Nadie sabe todavía la causa del cáncer de mama. Existen teorías que apuntan a los virus y la teoría de la "ruptura de inmunidad del sistema” del cáncer en general. En el caso de cáncer de mama han sido descartadas varias teorías fantasiosas (no se contrae por golpes, partos, contagio, etc.) y sólo tres o cuatro líneas de investigación parecen algo prometedoras. Causas posibles - Dieta o medio ambiente: Es posiblemente la causa más sospechosa. Hay estudios que prueban que cuando las mujeres ja...

Micro-channel plate photon detector studies for the TORCH detector

Energy Technology Data Exchange (ETDEWEB)

Castillo García, L., E-mail: lucia.castillo.garcia@cern.ch [CERN, PH Department, CH-1211, Geneva 23 (Switzerland); Laboratory for High Energy Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Brook, N.; Cowie, E.N.; Cussans, D. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Forty, R.; Frei, C. [CERN, PH Department, CH-1211, Geneva 23 (Switzerland); Gao, R. [Department of Physics, University of Oxford, Oxford OXI 3RH (United Kingdom); Gys, T. [CERN, PH Department, CH-1211, Geneva 23 (Switzerland); Harnew, N. [Department of Physics, University of Oxford, Oxford OXI 3RH (United Kingdom); Piedigrossi, D. [CERN, PH Department, CH-1211, Geneva 23 (Switzerland); Van Dijk, M. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

2015-07-01

The Time Of internally Reflected Cherenkov light (TORCH) detector is under development. Charged particle tracks passing through a 1 cm plate of quartz will generate the Cherenkov photons, and their arrival will be timed by an array of micro-channel plate photon detectors. As part of the TORCH R&D studies, commercial and custom-made micro-channel plate detectors are being characterized. The final photon detectors for this application are being produced in a three-phase program in collaboration with industry. Custom-made single-channel devices with extended lifetime have been manufactured and their performance is being systematically investigated in the laboratory. Optical studies for the preparation of beam and laboratory tests of a TORCH prototype are also underway.

CANCER DE MAMA EN COLOMBIA

Directory of Open Access Journals (Sweden)

Mario A. González Mariño

2014-12-01

Full Text Available OBJETIVO: Conocer la situación del cáncer de mama en Colombia mediante la revisión de publicaciones epidemiológicas y clínicas. MATERIALES Y MÉTODOS: Evaluación de estudios publicados en revistas científicas seriadas sobre cáncer de mama en Colombia mediante búsqueda en las bases de datos Medline con los términos neoplasm and breast and Colombia y Lilacs con neoplasia y mama y Colombia. Se seleccionaron los estudios con aplicación epidemiológica o clínica con muestreo o datos de mujeres residentes en Colombia, ubicando sus resultados en la sección de introducción y en la de discusión de acuerdo con los enfoques de promoción, prevención y tratamiento. RESULTADOS: Se encontraron 62 referencias en Medline de las que se seleccionaron 23 y en Lilacs de 16 se escogieron 4. Las referencias se descartaron en Medline por las siguientes razones: 15 por el diseño de estudio (revisión de tema, presentación de casos clínicos, 7 por tratarse de investigación básica, 10 por tema diferente al cáncer de mama en Colombia y 7 por datos pertenecientes a otro país. En Lilacs se excluyeron por: 7 artículos también presentes en Medline, 3 por diseño, 1 de investigación básica y 1 de un tema diferente. CONCLUSIONES: Los artículos revisados permiten tener una visión integral sobre el cáncer de mama en Colombia. En ellos se puede verificar que hay limitaciones en la prestación del servicio de atención en salud para esta enfermedad, y se identifican factores de riesgo con significancia estadística como la nuliparidad, niveles altos de inactividad física y exposición a DDE (diclorodifenildicloroeteno y para el cáncer genético se encontraron mutaciones fundadoras. La consulta se hace principalmente por síntomas, no sobre resultados de cribado como sería lo deseable. Existen también contribuciones sobre el manejo quirúrgico y adyuvante extrapolables a las condiciones del país.

Retorno al trabajo tras cáncer de mama

OpenAIRE

López-Guillén García, Araceli; Vicente Pardo, José Manuel

2017-01-01

Resumen El cáncer de mama frecuentemente es causa de largos procesos de baja. La duración media de las bajas por cáncer de mama es de unos 320 días, estando entre los tres procesos principales que causan bajas de más de 365 días junto con la lumbalgia y el trastorno ansioso depresivo. Cada año se producen 26.000 casos nuevos en España de los que en su mayoría se producen en plena edad laboral. La supervivencia a los cinco años entre mujeres de 30 a 60 años es del 86%. El cáncer de mama es la ...

Hamartoma de la mama Breast hamartoma

Directory of Open Access Journals (Sweden)

Mercedes Pérez Vázquez

2004-06-01

Full Text Available El hamartoma de la mama o fibroadenolipoma de la mama es una lesión nodular que puede simular un fibroadenoma o un tumor phyllodes . Aparece en las mujeres en la edad media de la vida y se presenta clínicamente como un nódulo bien definido e indoloro. El diagnóstico imagenológico es el que hace pensar en éste, ya que es un tumor poco frecuente. Histológicamente cumple los requisitos generales de un hamartoma: mezcla desordenada de tejidos maduros y especializados. En la mama se puede apreciar estructura ductal y lobulillar con estroma fibroso, tejido adiposo y en ocasiones, tejido muscular liso. En este trabajo se presenta un caso de una paciente de 40 años con un hamartoma de la mama derecha que histológicamente mostraba además, tejido óseo y cartilaginosoBreast hamartoma or breast fibroadenolipoma is a nodular lesion that may resemble a fibroadenoma or phyllodes tumor. It appears in middle-aged women and it clinically presents as a well defined and painless nodule. The imaging diagnosis makes to think about it, since it is an uncommon tumor. From the histological point of view, it fulfills the general requirements of a hamartoma: disarranged combination of mature and specialized tissues. Ductal and lobular structure with fibrous stroma, fat tissue and, on occasions, smooth muscular tissue, may be observed in the breast. A case of a 40-year-old female patient with a hamartoma of the right mamma that histologically showed osteal and cartilaginous tissue is reported

High power vertical stacked and horizontal arrayed diode laser bar development based on insulation micro-channel cooling (IMCC) and hard solder bonding technology

Science.gov (United States)

Wang, Boxue; Jia, Yangtao; Zhang, Haoyu; Jia, Shiyin; Liu, Jindou; Wang, Weifeng; Liu, Xingsheng

2018-02-01

An insulation micro-channel cooling (IMCC) has been developed for packaging high power bar-based vertical stack and horizontal array diode lasers, which eliminates many issues caused in its congener packaged by commercial copper formed micro-channel cooler(MCC), such as coefficient of thermal expansion (CTE) mismatch between cooler and diode laser bar, high coolant quality requirement (DI water) and channel corrosion and electro-corrosion induced by DI water if the DI-water quality is not well maintained The IMCC cooler separates water flow route and electrical route, which allows tap-water as coolant without electro-corrosion and therefore prolongs cooler lifetime dramatically and escalated the reliability of these diode lasers. The thickness of ceramic and copper in an IMCC cooler is well designed to minimize the CTE mismatch between laser bar and cooler, consequently, a very low "SMILE" of the laser bar can be achieved for small fast axis divergence after collimation. In additional, gold-tin hard solder bonding technology was also developed to minimize the risk of solder electromigration at high current density and thermal fatigue under hard-pulse operation mode. Testing results of IMCC packaged diode lasers are presented in this report.

Detección precoz del cancer de mama, la mamografía y el autoexamen

OpenAIRE

Abella Calle, José; Fundación Valle de Lili

2001-01-01

Problemática mundial/ ¿Qué causa el cáncer de mama?/Factores de riesgo/ ¿Cómo podemos detectar precozmente el cáncer de mama?/ ¿Qué es la mamografía?/La ecografía en el estudio de las mamas/Los rayos X y el cáncer/El autoexamen de las mamas.

A microfluidic platform for generating large-scale nearly identical human microphysiological system arrays

Science.gov (United States)

Hsu, Yu-Hsiang; Moya, Monica L.; Hughes, Christopher C.W.; Georgea, Steven C.; Lee, Abraham P.

2013-01-01

This paper reports a polydimethylsiloxane microfluidic model system that can develop an array of nearly identical human microtissues with interconnected vascular networks. The microfluidic system design is based on an analogy with an electric circuit, applying resistive circuit concepts to design pressure dividers in serially-connected microtissue chambers. A long microchannel (550, 620 and 775 mm) creates a resistive circuit with a large hydraulic resistance. Two media reservoirs with a large cross-sectional area and of different heights are connected to the entrance and exit of the long microchannel to serve as a pressure source, and create a near constant pressure drop along the long microchannel. Microtissue chambers (0.12 μl) serve as a two-terminal resistive component with an input impedance > 50-fold larger than the long microchannel. Connecting each microtissue chamber to two different positions along the long microchannel creates a series of pressure dividers. Each microtissue chamber enables a controlled pressure drop of a segment of the microchannel without altering the hydrodynamic behaviour of the microchannel. The result is a controlled and predictable microphysiological environment within the microchamber. Interstitial flow, a mechanical cue for stimulating vasculogenesis, was verified by finite element simulation and experiments. The simplicity of this design enabled the development of multiple microtissue arrays (5, 12, and 30 microtissues) by co-culturing endothelial cells, stromal cells, and fibrin within the microchambers over two and three week periods. This methodology enables the culturing of a large array of microtissues with interconnected vascular networks for biological studies and applications such as drug development. PMID:23723013

CFD Analysis for Optimum Thermal Design of Carbon Nanotube Based Micro-Channel Heatsink

Directory of Open Access Journals (Sweden)

M. Mahbub

2011-10-01

Full Text Available Carbon nanotube (CNT is considered as an ideal material for thermal management in electronic packaging because of its extraordinary high thermal conductivity. Fabricated onto a silicon substrate to form micro-channels, the CNT based cooling fins show high heat dissipation efficiency. A series of 2D and 3D CFD simulations have been carried out for CNT based micro-channel cooling architectures based on one and two dimensional fin array in this paper using COMSOL 4.0a software. Micro-channels are generally regarded as an effective method for the heat transfer in electronic products. The influence of various fluids, micro-fin structures, fluid velocity and heating powers on cooling effects have been simulated and compared in this study. Steady-state thermal stress analyses for the forced convection heat transfer are also performed to determine maximum allowable stress and deflections for the different types of cooling assembly.

Detección precoz del cáncer de mama

OpenAIRE

Uriarte Salterain, Andrea

2012-01-01

El cáncer de mama constituye un importante problema de salud en los países desarrollados por su elevada incidencia y mortalidad. El cáncer de mama es el tumor maligno más frecuente y una de las primeras causas de muerte por cáncer en las mujeres

New Yorgi La Mama hakkab mängima Oksase "Puhastust" / Andrers Laasik

Index Scriptorium Estoniae

Laasik, Andres, 1960-2016

2010-01-01

Sõltumatus teatris La Mama toimub veebruaris 2011 Sofi Oksase näidendi "Puhastus" esietendus Ameerika mandril. Lavastaja Zishan Ugurlu. La Mamas mängitud eesti autorite näidenditest ja lavastustest

MAMA- User Feedback and Training Summary

Energy Technology Data Exchange (ETDEWEB)

Porter, Reid B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ruggiero, Christy E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-05-21

This document describes the current state of the MAMA (Morphological Analysis of Materials) software user identified bugs, issues, and requests for improvements. It also lists Current users and current training methods.

Non-Photolithographic Manufacturing Processes for Micro-Channels Functioned by Micro-Contact-Printed SAMs

Science.gov (United States)

Saigusa, Hiroki; Suga, Yasuo; Miki, Norihisa

In this paper we propose non-photolithographic fabrication processes of micro-fluid channels with patterned SAMs (Self-Assembled-Monolayers). SAMs with a thiol group are micro-contact printed on a patterned Au/Ti layer, which is vapor-deposited through a shadow mask. Ti is an adhesion layer. Subsequently, the micro-channels are formed by bonding surface-activated PDMS onto the silicon substrate via a silanol group, producing a SAMs-functioned bottom wall of the micro-channel. No photolithographic processes are necessary and thus, the proposed processes are very simple, quick and low cost. The micro-reactors can have various functions associated with the micro-contact-printed SAMs. We demonstrate successful manufacturing of micro-reactors with two types of SAMs. The micro-reactor with patterned AUT (11-amino-1-undecanethiol) successfully trapped nano-particles with a carboxylic acid group, indicating that micro-contact-printed SAMs remain active after the manufacturing processes of the micro-reactor. AUT -functioned micro-channels are applicable to bioassay and to immobilize proteins for DNA arrays. ODT (1-octadecanethiol) makes surfaces hydrophobic with the methyl terminal group. When water was introduced into the micro-reactor with ODT-patterned surfaces, water droplets remained only in the hydrophilic areas where ODT was not patterned. ODT -functioned micro-channels are applicable to fluid handling.

Design and fabrication of magnetically functionalized flexible micropillar arrays for rapid and controllable microfluidic mixing

KAUST Repository

Zhou, BingPu

2015-03-25

Magnetically functionalized PDMS-based micropillar arrays have been successfully designed, fabricated and implanted for controllable microfluidic mixing. The arrangement of PDMS micropillar arrays inside the microchannel can be flexibly controlled by an external magnetic field. As a consequence, the flow fields inside the microchannel can be regulated at will via magnetic activation conveniently. When a microchannel is implanted with such micropillar arrays, two microstreams can be mixed easily and controllably upon the simple application of an on/off magnetic signal. Mixing efficiencies based on micropillar arrays with different densities were investigated and compared. It was found that micropillar arrays with higher density (i.e. smaller pillar pitch) would render better mixing performance. Our microfluidic system is capable of generating highly reproducible results within many cycles of mixing/non-mixing conversion. We believe that the simple mixing-triggering method together with rapid and controllable mixing control will be extraordinarily valuable for various biological or chemical applications in the future. This journal is © The Royal Society of Chemistry 2015.

Design and fabrication of magnetically functionalized flexible micropillar arrays for rapid and controllable microfluidic mixing

KAUST Repository

Zhou, BingPu; Xu, Wei; Syed, Ahad; Chau, Yeungyeung; Chen, Longqing; Chew, Basil; Yassine, Omar; Wu, Xiaoxiao; Gao, Yibo; Zhang, Jingxian; Xiao, Xiao; Kosel, Jü rgen; Zhang, Xixiang; Yao, Zhaohui; Wen, Weijia

2015-01-01

Magnetically functionalized PDMS-based micropillar arrays have been successfully designed, fabricated and implanted for controllable microfluidic mixing. The arrangement of PDMS micropillar arrays inside the microchannel can be flexibly controlled by an external magnetic field. As a consequence, the flow fields inside the microchannel can be regulated at will via magnetic activation conveniently. When a microchannel is implanted with such micropillar arrays, two microstreams can be mixed easily and controllably upon the simple application of an on/off magnetic signal. Mixing efficiencies based on micropillar arrays with different densities were investigated and compared. It was found that micropillar arrays with higher density (i.e. smaller pillar pitch) would render better mixing performance. Our microfluidic system is capable of generating highly reproducible results within many cycles of mixing/non-mixing conversion. We believe that the simple mixing-triggering method together with rapid and controllable mixing control will be extraordinarily valuable for various biological or chemical applications in the future. This journal is © The Royal Society of Chemistry 2015.

Flow Boiling in a Micro-Channel Coated With Carbon Nanotubes

OpenAIRE

Khanikar, Vikash; Mudawar, Issam; Fisher, Timothy

2009-01-01

This study examines the heat transfer enhancement attributes of carbon nanotubes (CNTs) applied to the bottom wall of a shallow rectangular micro-channel. Using deionized water as working fluid, experiments were performed with both a bare copper bottom wall and a CNT-coated copper wall. Boiling curves were generated for both walls, aided by high-speed video analysis of interfacial features. CNT arrays promoted earlier, abundant and intense bubble nucleation at low mass velocities, consistent ...

Carcinomatosis peritoneal secundaria a carcinoma Lobulillar de mama

OpenAIRE

PRIEGO J,PABLO; RODRÍGUEZ V,GLORIA; REGUERO C,Mª EUGENIA; CABANAS M,JACOBO; LISA C,EDUARDO; PEROMINGO F,ROBERTO; FRESNEDA M,VIRGILIO

2007-01-01

Introducción: Aunque el cáncer de mama metastatiza con mayor frecuencia en ganglios linfáticos, hueso, pulmón e hígado, también se puede extender hacia el tracto gastrointestinal, peritoneo y órganos ginecológicos. Material y Método: Describimos tres casos de carcinomatosis peritoneal secundaria a la diseminación metastásica de un carcinoma lobulillar infiltrante de mama. En los tres casos el diagnóstico se hizo varios años después del descubrimiento del tumor primario y en dos de ellos se ob...

Application of two-phase flow for cooling of hybrid microchannel PV cells: A comparative study

International Nuclear Information System (INIS)

Valeh-e-Sheyda, Peyvand; Rahimi, Masoud; Karimi, Ebrahim; Asadi, Masomeh

2013-01-01

Highlights: ► Showing cooling potential of gas–liquid two-phase flow in microchannels for PV cell. ► Introducing the concept of using slug flow in microchannels for cooling of PV cells. ► In single-phase flow, increasing the liquid flow rate enhances the PV power. ► Showing that in two-phase flow the output power related the fluid flow regime. ► By coupling PV and microchannel an increase up to 38% in output power was observed. - Abstract: This paper reports the experimental data from performance of two-phase flows in a small hybrid microchannel solar cell. Using air and water as two-phase fluid, the experiments were conducted at indoor condition in an array of rectangular microchannels with a hydraulic diameter of 0.667 mm. The gas superficial velocity ranges were between 0 and 3.27 m s −1 while liquid flow rate was 0.04 m s −1 . The performance analysis of the PV cell at slug and transitional slug/annular flow regimes are the focus of this study. The influence of two-phase working fluid on PV cell cooling was compared with single-phase. In addition, the great potential of slug flow for heat removal enhancement in PV/T panel was investigated. The obtained data showed the proposed hybrid system could substantially increases the output power of PV solar cells

CÁNCER DE MAMA Y DIETA: REVISIÓN

OpenAIRE

Fernández Ortega, Jairo Alejandro

2010-01-01

El cáncer es una de las principales causas de mortalidad y el número total de casos está aumentando en todo el mundo. En las mujeres, el cáncer de mama es el segundo cáncer más frecuente, su aparición está asociada a varios factores de riesgo: como estilos de vida poco sanos (consumo de tabaco y alcohol, dieta inadecuada, falta de actividad física) y exposición a carcinógenos. El propósito de este estudio es identificar y comprender las relaciones entre la dieta y el riesgo de cáncer de mama....

Separation process using microchannel technology

Science.gov (United States)

Tonkovich, Anna Lee [Dublin, OH; Perry, Steven T [Galloway, OH; Arora, Ravi [Dublin, OH; Qiu, Dongming [Bothell, WA; Lamont, Michael Jay [Hilliard, OH; Burwell, Deanna [Cleveland Heights, OH; Dritz, Terence Andrew [Worthington, OH; McDaniel, Jeffrey S [Columbus, OH; Rogers, Jr; William, A [Marysville, OH; Silva, Laura J [Dublin, OH; Weidert, Daniel J [Lewis Center, OH; Simmons, Wayne W [Dublin, OH; Chadwell, G Bradley [Reynoldsburg, OH

2009-03-24

The disclosed invention relates to a process and apparatus for separating a first fluid from a fluid mixture comprising the first fluid. The process comprises: (A) flowing the fluid mixture into a microchannel separator in contact with a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the first fluid is sorbed by the sorption medium, removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing first fluid from the sorption medium and removing desorbed first fluid from the microchannel separator. The process and apparatus are suitable for separating nitrogen or methane from a fluid mixture comprising nitrogen and methane. The process and apparatus may be used for rejecting nitrogen in the upgrading of sub-quality methane.

Performance test of miniature heat exchangers with microchannels

International Nuclear Information System (INIS)

Hong, Yong Ju; Koh, Deuk Yong

2005-01-01

Etched microchannel heat exchanger, a subfield within MEMS, has high heat flux capability. This capability makes microchannels well-suited for a wide variety of application of cooling and chemical reaction. In this study, counter flow type miniature heat exchangers, which have flat metal plates with chemically etched microchannels, were manufactured by brazing method. Four type of the heat exchangers, which have straight microchannels, wavy shape microchannels, pin-fin channels and serpentine shape microchannels, were investigated to compare their thermal and hydraulic performance. Gas to gas heat exchange experiments were performed to measure the pressure drop and effectiveness of the heat exchangers at given gas flow rates and temperature difference

Field-effect Flow Control in Polymer Microchannel Networks

Science.gov (United States)

Sniadecki, Nathan; Lee, Cheng S.; Beamesderfer, Mike; DeVoe, Don L.

2003-01-01

A new Bio-MEMS electroosmotic flow (EOF) modulator for plastic microchannel networks has been developed. The EOF modulator uses field-effect flow control (FEFC) to adjust the zeta potential at the Parylene C microchannel wall. By setting a differential EOF pumping rate in two of the three microchannels at a T-intersection with EOF modulators, the induced pressure at the intersection generated pumping in the third, field-free microchannel. The EOF modulators are able to change the magnitude and direction of the pressure pumping by inducing either a negative or positive pressure at the intersection. The flow velocity is tracked by neutralized fluorescent microbeads in the microchannels. The proof-of-concept of the EOF modulator described here may be applied to complex plastic ,microchannel networks where individual microchannel flow rates are addressable by localized induced-pressure pumping.

Comparison of the automated evaluation of phantom mama in digital and digitalized images; Comparacao da avaliacao automatizada do phantom mama em imagens digitais e digitalizadas

Energy Technology Data Exchange (ETDEWEB)

Santana, Priscila do Carmo, E-mail: pcs@cdtn.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares; Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Medicina. Dept. de Propedeutica Complementar; Gomes, Danielle Soares; Oliveira, Marcio Alves; Nogueira, Maria do Socorro, E-mail: mnogue@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Mammography is an essential tool for diagnosis and early detection of breast cancer if it is provided as a very good quality service. The process of evaluating the quality of radiographic images in general, and mammography in particular, can be much more accurate, practical and fast with the help of computer analysis tools. This work compare the automated methodology for the evaluation of scanned digital images the phantom mama. By applied the DIP method techniques was possible determine geometrical and radiometric images evaluated. The evaluated parameters include circular details of low contrast, contrast ratio, spatial resolution, tumor masses, optical density and background in Phantom Mama scanned and digitized images. The both results of images were evaluated. Through this comparison was possible to demonstrate that this automated methodology is presented as a promising alternative for the reduction or elimination of subjectivity in both types of images, but the Phantom Mama present insufficient parameters for spatial resolution evaluation. (author)

Uncertainty in the use of MAMA software to measure particle morphological parameters from SEM images

Energy Technology Data Exchange (ETDEWEB)

Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-06-05

The MAMA software package developed at LANL is designed to make morphological measurements on a wide variety of digital images of objects. At LANL, we have focused on using MAMA to measure scanning electron microscope (SEM) images of particles, as this is a critical part of our forensic analysis of interdicted radiologic materials. In order to successfully use MAMA to make such measurements, we must understand the level of uncertainty involved in the process, so that we can rigorously support our quantitative conclusions.

Cáncer de mama, su caracterización epidemiológica

Directory of Open Access Journals (Sweden)

Yisel de la Caridad Ramos Águila

2015-08-01

Full Text Available Introducción: el cáncer de mama constituye un problema de salud, ocupando la segunda causa de muerte por cáncer en mujeres. Objetivo: describir los aspectos epidemiológicos del cáncer de mama en las mujeres del municipio Pinar del Río en el período 2012-2013. Material y método: se realizó una investigación observacional, descriptiva. El universo de estudio lo constituyeron todas las mujeres del municipio Pinar del Río con diagnóstico clínico y anátomo-patológico de cáncer de mama (N=135, atendidas en el hospital oncológico de la provincia en los años 2012 y 2013. Para la obtención de la información se aplicó una encuesta cuyas variables principales recogían datos demográficos (edad, antecedentes personales de lesiones benignas y malignas y familiares de cáncer de mama, elementos relacionados con el estado nutricional, los estilos de vida de las pacientes, así como sus características endocrino-reproductivas. El procesamiento estadístico de los datos se realizó utilizando medidas de resumen para variables cualitativas (frecuencias absolutas y porcentajes y para variables cuantitativas (promedio. Resultados: predominó la enfermedad entre los 50 y 69 años de edad. Los factores de riesgo más frecuentes fueron menarquía precoz, no ofrecimiento o menos de 4 meses de lactancia materna y uso de anticonceptivos hormonales. Conclusión: en las mujeres estudiadas se identificó, al menos, un factor de riesgo conocido para desarrollar cáncer de mama, aunque la no existencia de estos no excluye la posibilidad de padecerlo.

Instability in flow boiling in microchannels

CERN Document Server

Saha, Sujoy Kumar

2016-01-01

This Brief addresses the phenomena of instability in flow boiling in microchannels occurring in high heat flux electronic cooling. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Critical Heat Flux in Flow Boiling in Microchannels,” and "Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,"by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

Nivel de adaptación y afrontamiento en las mujeres con cáncer de mama

Directory of Open Access Journals (Sweden)

Yoeli Leyva-Pescador

2011-12-01

Full Text Available Introducción: El cáncer de mama constituye una amenaza para la salud por ser la segunda causa de muerte en la mujer de 30 a 50 años de edad. El diagnostico, tratamiento y recuperación de las mujeres con cáncer de mama genera situaciones estresantes, la forma en cómo se afrontan influye en la adaptación. Objetivo: Conocer el nivel de adaptación y afrontamiento de las mujeres con cáncer de mama, atendidas en una institución de salud de Durango, Dgo. México. Materiales y Métodos: Estudio descriptivo cuantitativo, aplicando instrumento validado en población mexicana con un (alfa .7969, "escala de medición del proceso de afrontamiento y adaptación" de Callista Roy" en 22 mujeres con cáncer de mama. Resultados: Las mujeres con cáncer de mama se adaptan y afrontan su problema de salud, con un nivel de adaptación integrado y compensatorio pudiendodistinguir que dónde presenta dificultad es en el modo físico y fisiológico. Discusión y Conclusiones: De acuerdo al estudio "ajuste psicosocial y afrontamiento en pacientes con cáncer de mama" se encuentra una diferencia en que los participantes no experimentaron cambios a partir de la enfermedad contraria a nuestro trabajo ya que los participantes adquieren nuevas posibilidades y capacidades. La adaptación de las mujeres que han padecido cáncer de mama es un proceso dinámico, enfrentan múltiples desequilibrios que afectan sus dimensiones emocional, física, mental y social. Se pudo conocer el nivel de adaptación y afrontamiento de las mujeres con cáncer de mama comprobando que en su mayoría presentan un nivel de adaptación integrado y compensatorio. (Rev Cuid 2011; 2(2: 96- 104Palabras clave: Adaptación Psicológica, Atención de Enfermería, Cáncer de Mama. (Fuente: DeCs BIREME.

A review of entropy generation in microchannels

Directory of Open Access Journals (Sweden)

Mohamed M Awad

2015-12-01

Full Text Available In this study, a critical review of thermodynamic optimum of microchannels based on entropy generation analysis is presented. Using entropy generation analysis as evaluation parameter of microchannels has been reported by many studies in the literature. In these studies, different working fluids such as nanofluids, air, water, engine oil, aniline, ethylene glycol, and non-Newtonian fluids have been used. For the case of nanofluids, “nanoparticles” has been used in various kinds such as Al2O3 and Cu, and “base fluid” has been used in various kinds such as water and ethylene glycol. Furthermore, studies on thermodynamic optimum of microchannels based on entropy generation analysis are summarized in a table. At the end, recommendations of future work for thermodynamic optimum of microchannels based on entropy generation analysis are given. As a result, this article can not only be used as the starting point for the researcher interested in entropy generation in microchannels, but it also includes recommendations for future studies on entropy generation in microchannels.

A highly stable microchannel heat sink for convective boiling

International Nuclear Information System (INIS)

Lu, Chun Ting; Pan Chin

2009-01-01

To develop a highly stable two-phase microchannel heat sink, we experimented with convective boiling in diverging, parallel microchannels with different distributions of laser-etched artificial nucleation sites. Each microchannel had a mean hydraulic diameter of 120 µm. The two-phase flow visualization and the magnitudes of pressure drop and inlet temperature oscillations under boiling conditions demonstrated clearly the merits of using artificial nucleation sites to further stabilize the flow boiling in diverging, parallel microchannels. The stability map showed the plane of subcooling number versus phase change number. It illustrated that diverging, parallel microchannels with artificial nucleation cavities have a much wider stable region than parallel microchannels with uniform cross-sections or diverging, parallel microchannels without artificial nucleation cavities. In addition, the results revealed that the design with cavities distributed uniformly along the downstream half of the channel presented the best stability performance among the three distributions of nucleation sites. This particular design can be regarded as a highly stable microchannel heat sink for convective boiling

Gain stabilized microchannel plates and a treatment method for microchannel plates

International Nuclear Information System (INIS)

1979-01-01

Microchannel plates having increased gain and significantly improved aging characteristics are provided by forming a thin film of a cesium compound on the channel walls. In an exemplary embodiment, a suface film of cesium hydroxide is applied to the interior wall surfaces of an MCP by saturating the plate with a solution of the compound, then allowing the solvent to evaporate. The cesium hydroxide residue on the walls subsequently is converted to cesium oxide by a high temperature bake. Microchannel plates are used in image amplifiers, radiation detectors and such like equipment. (Auth.)

Cancro de mama hereditário: marcadores genéticos

OpenAIRE

Morais, Leonor de Sousa

2016-01-01

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz O cancro de mama é atualmente uma das doenças que mais afeta o sexo feminino, a incidência tem vindo a aumentar ao longo dos anos levando a comunidade científica a aprofundar o conhecimento sobre os mecanismos que provocam a cancerização e qual o papel da genética neste processo. Há 20 anos foram identificados os genes que contribuem para o desenvolvimento do cancro de mama hereditário, como o...

Optimization of triangular microchannel heat sinks using constructible theory

International Nuclear Information System (INIS)

Mardani, Moloud; Salimpour, Mohammad Reza

2016-01-01

The present paper examines the optimization of triangular microchannel heat sinks. The impact of volume fraction of solid material and pressure drop on the maximum temperature of the microchannel heat sinks are investigated and their optimum operating conditions are compared. From the results, it is seen that increasing the side angle of the triangular microchannel, improves its performance. Furthermore, there is an appropriate agreement between the analytical and numerical results. Finally, the effect of degrees of freedom on the performance of microchannels is investigated. To accomplish this end, the triangular microchannels with the side angle of 60 degree have been chosen as it has the best performance compared to other microchannels. It is observed that the minimized maximum temperatures of optimized microchannel heat sinks with three degrees of freedom are 10% lower than the ones with two degrees of freedom

Nanoparticle-Assisted Diffusion Brazing of Metal Microchannel Arrays: Nanoparticle Synthesis, Deposition, and Characterization

Science.gov (United States)

Eluri, Ravindranadh T.

Microchannel process technology (MPT) offers several advantages to the field of nanomanufacturing: 1) improved process control over very short time intervals owing to shorter diffusional distances; and 2) reduced reactor size due to high surface area to volume ratios and enhanced heat and mass transfer. The objective of this thesis was to consider how nanomaterials, produced in part using MPT, could be used to solve problems associated with the fabrication of MPT devices. Specifically, many MPT devices are produced using transient liquid-phase brazing involving an electroplated interlayer consisting of a brazing alloy designed for melting temperature suppression. Unfortunately, these alloys can form brittle secondary phases which significantly reduce bond strength. In contrast, prior efforts have shown that it is possible to leverage the size-dependent properties of nanomaterials to suppress brazing temperatures. In this prior work, thin films of off-the-shelf elemental nanoparticles were used as interlayers yielding joints with improved mechanical properties. In the present investigation, efforts have been made to characterize the synthesis and deposition of various elemental nanoparticle suspensions for use in the transient liquid-phase brazing of aluminum and stainless steel. Advances were used to demonstrate the nanoparticle-assisted diffusion brazing of a microchannel array. In the first section, a silver nanoparticle (AgNP) interlayer was produced for the diffusion brazing of heat exchanger aluminum. Efforts are made to examine the effect of braze filler particle size (˜5 nm and ˜50 nm) and processing parameters (heating rate: 5ºC/min and 25ºC/min; brazing temperature: 550ºC and 570ºC) on thin coupons of diffusion-brazed 3003 Al. A tensile strength of 69.7 MPa was achieved for a sample brazed at 570°C for 30 min under 1 MPa with an interlayer thickness of approximately 7 microm. Further suppression of the brazing temperature to 500ºC was achieved by

Cáncer de mama y exposición a hidrocarburos aromáticos

Directory of Open Access Journals (Sweden)

Ruth De Celis

2006-01-01

Full Text Available Los factores de riesgo que se han establecido para desarrollar cáncer de mama, no han podido explicar el incremento de este tipo de enfermedad en más de 50 por ciento de los casos. Debido a estas circunstancias, en los últimos 20 años se ha iniciado el estudio de factores ambientales, especialmente de las sustancias químicas que han mostrado tener actividad similar a los estrógenos (xenoestrógenos y con capacidad de estimular el tejido glandular de la mama. Los hidrocarburos aromáticos policíclicos han sido de mucho interés debido a su amplia distribución, persistencia en el ambiente por largos periodos y por su capacidad de bioacumularse en los alimentos y en el tejido adiposo de humanos y animales. Hasta la fecha, se han realizado numerosos estudios de tipo descriptivo, estudios de cohorte, epidemiológicos, de grupos seleccionados, que incluyen aspectos genéticos, alimentación, menopausia, métodos anticonceptivos y lactancia materna, en asociación con la formación de tumores de mama. En algunas de estas investigaciones se ha demostrado que los hidrocarburos guardan una estrecha relación con el cáncer de mama, en otros estudios no se ha podido sustentar esta relación. En esta revisión se realiza una compilación de los estudios más representativos de los principales tipos de hidrocarburos y su relación con el cáncer de mama

Dieta, obesidad y sedentarismo como factores de riesgo del cáncer de mama

Directory of Open Access Journals (Sweden)

Carlos Antonio Oliva Anaya

Full Text Available El cáncer de mama es la primera causa de muerte por tumores malignos entre las mujeres. Una dieta no saludable, el sedentarismo y la obesidad son factores de riesgo importantes para padecer cáncer de mama, sobre todo en mujeres posmenopáusicas. El objetivo del presente trabajo es revisar los estudios epidemiológicos más relevantes sobre dieta, obesidad y cáncer de mama en las mujeres. Se estableció una estrategia de información, educación y comunicación social como apoyo a las acciones del Programa Nacional de Control de Cáncer Mamario. Para la prevención y tratamiento de la obesidad e incidencia de cáncer de mama es necesario actividades de educación nutricional, para producir cambios en los patrones y hábitos alimentarios y por consiguiente de estilos de vida, que promuevan una dieta más variada y el aumento del ejercicio físico, entre otros aspectos.

MAMA MODEL APPROACH: ITS IMPLICATION TO COMMITMENT AND ORGANIZATIONAL CITEZENSHIP BEHAVIOR OF OPERATIONAL HOTEL EMPLOYEE

Directory of Open Access Journals (Sweden)

Ida Bagus Gede Udiyana

2015-09-01

Full Text Available The aims of this study is to find the existence of MAMA (Motivation, Ability, and Moral Awareness model to the commitment and Organizational Citizenship Behavior (OCB. The subject of the research is the five stars hotels at Nusa Dua Bali. Respondents of this study are the operational employees at the hotels who have Hindu religion with 198 samples. The method of collecting data was simple random sampling method with proportional allocation. Structural Equation Modeling (SEM analysis technique was utilized to analyze the data in this research. This research has found that MAMA model (Motivation, Ability, and Moral Awareness influences OCB. Furthermore this research has found a theory that the main variable which is causing the appearance of organizational citizenship behavior is MAMA (motivation, ability, and moral awareness as an intrinsic behavior, and commitment or organizational citizenship behavior function of MAMA, and commitment or to be formulated as OCB f. Info

Terapia combinada con Trastuzumab en el tratamiento del Cáncer de mama: eficacia y efectos adversos

OpenAIRE

Hernández Martín, María Sol

2015-01-01

Introducción: El cáncer de mama es el más frecuente entre la población femenina. Entre un 25-30% de los cánceres de mama son HER2-positivo. Este tipo de cáncer, se ha relacionado con una mayor agresividad clínica e histológica, mayor riesgo de recurrencia y muerte asociada al cáncer de mama. Trastuzumab, es un anticuerpo monoclonal humanizado contra este receptor. Actualmente se dispone de cuatro agentes anti-HER2 autorizados: Trastuzumab, Pertuzumab, Lapatinib y Trastuzumab...

Bienestar psicológico y cáncer de mama

Directory of Open Access Journals (Sweden)

Carmen Regina Victoria García Viniegras

2007-01-01

Full Text Available Se plantean los aspectos psicológicos más relevantes estudiados en las mujeres con cáncer de mama, tales como estilos de afrontamiento, preocupaciones, valoracionesde su enfermedad y efectos psicológicos del tratamiento. Se analizan los determinantes del bienestar psicológico de las pacientes, tales como la autoconfianza, la estabilidad emocional, la fortaleza, la afectividad positiva y la autoestima, así como el afrontamiento satisfactorio a situaciones de estrés, entre ellas al estrés de la enfermedad, y a los cambios que esta impone en el estilo de vida.Se considera en este análisis la influencia de determinadas variables sociodemográficas, así como de variables clínicas, que influyen en la calidadde vida y el bienestar de las pacientes con cáncer de mama. Se destaca la necesidad de que las estrategias de atención sanitaria a las pacientes con cáncer de mama incluyan elementos clínico-psicológicos que promuevan una mejoría del bienestar psicológico de estas mujeres.

Câncer de mama: relato de caso e critérios de diagnóstico

OpenAIRE

José Geraldo de Alencar Santos Júnior; Ivonete Aparecida Alves Sampaio; Polyana Amorim Cruz Nascimento; Ana Bruna Macêdo Matos; Sáskia Thamyles Bezerra Coutinho; Audrey Taveira de Souza Silva; José Wanderson Carvalho Noronha; João Pedro Viana Rodrigues; Thamara Caroline Cardoso Melo

2018-01-01

Objetivos: O objetivo do trabalho foi mostrar quais os de critérios de diagnósticos, do câncer de mama. Descrição do caso: M.S.S., 83 anos, sexo feminino, da cidade de Juazeiro do Norte/CE, solteira, aposentada por idade, nulípara, diabética e portadora de Alzheimer. Após sentir uma forte dor na mama e muita cefaleia, foi levada ao médico mastologista para uma consulta. Ao ser examinada, o médico diagnosticou um nódulo na mama direita, em seguida, pediu uma mamografia e um ultrassom mamário c...

Cáncer de mama y ejercicio físico: estudio piloto

OpenAIRE

Casla Barrio, S.; Sampedro Molinuelo, J.; López Díaz de Durana, A.; Coterón López, F.J.; Barakat Carballo, R.O.

2012-01-01

El cáncer de mama (CM) es el más común entre las mujeres occidentales, con un alto porcentaje de supervivencia, la cual no está exenta de numerosos efectos secundarios tanto por los tratamientos como por la enfermedad, afectando a la calidad de vida de estas mujeres. El objetivo de este proyecto es conocer el efecto de un programa de ejercicio físico conducido en la calidad de vida de mujeres afectadas por cáncer de mama. Método. El programa de ejercicio físico consistió en 24 sesiones (d...

Persistencia de las representaciones sociales del cáncer de mama

OpenAIRE

Giraldo-Mora, Clara V.

2012-01-01

Objetivo Comprender las representaciones sociales del cáncer de mama para un grupo de mujeres de la ciudad de Medellín, la influencia en su prevención y en las prácticas de autocuidado. Metodos Estudio cualitativo con 19 entrevistas semiestructuradas con mujeres adultas que no han tenido cáncer de mama, utilizando el criterio de máxima variación como técnica de muestreo. El análisis se orientó por la teoría fundamentada. Resultados Algunas mujeres tienen representaciones fisiológicas del cánc...

Afrontamiento al cáncer de mama en pacientes diagnosticadas.

Directory of Open Access Journals (Sweden)

Mónica Moreno Martín

2017-03-01

Full Text Available Introducción: El cáncer de mama representa la primera causa de muerte por cáncer en el sexo femenino y aceptar la idea de un cáncer es un asunto difícil de asimilar, por lo que el afrontamiento a esta enfermedad constituye un factor determinante en el transcurso de la misma. Objetivo: Describir el afrontamiento a la enfermedad de pacientes con cáncer de mama en el Servicio de Oncología del Hospital 10 de Octubre de la Habana.  Métodos: Se realizó un estudio observacional, descriptivo y de tipo transversal entre julio y noviembre del 2014. Se empleó el estudio de casos en profundidad. El universo estuvo constituido por 38 pacientes diagnosticadas de cáncer de mama que asistieron a la consulta de oncología. Bajo un diseño muestral no probabilístico de sujetos tipos, se seleccionaron 14 mujeres diagnosticadas de carcinoma de mama. Resultados: Las pacientes utilizaron estilos de afrontamientos centrados en la emoción y en el problema mostrando un ligero predominio en este último. Los recursos personales para el afrontamiento se caracterizaron por creencias positivas de control, creencias de optimismo y de religiosidad, acompañada también de creencias negativas de control externo y de identidad, así como la percepción salud y energía. Conclusiones: Hubo un ligero predominio al uso de estilos de afrontamiento centrados en el problema con estrategias de búsqueda de apoyo social y planificación. Las pacientes con estilos de afrontamiento centrados en las emociones utilizaron estrategias de distanciamiento y autocontrol.

Importancia de la pesquisa del cáncer de mama

OpenAIRE

Dinorah García Roque; Yaiset Borges de la Oliva

2017-01-01

El cáncer, es uno de los mayores problemas de Salud Pública en el mundo, siendo en términos epidemiológicos, la neoplasia maligna que más se diagnostica y la mayor causa de muerte en el sexo femenino. El cáncer de mama es el tumor más frecuente en mujeres, con una incidencia anual de casi 143 000 nuevos casos en los EEUU. Estas cifras han ido incrementándose progresivamente durante los últimos 50 años. En las Américas, el cáncer de mama es el más común y la segunda causa principal de muerte p...

Boiling in microchannels: a review of experiment and theory

International Nuclear Information System (INIS)

Thome, John R.

2004-01-01

A summary of recent research on boiling in microchannels is presented. The review addresses the topics of macroscale versus microscale heat transfer, two-phase flow regimes, flow boiling heat transfer results for microchannels, heat transfer mechanisms in microchannels and flow boiling models for microchannels. In microchannels, the most dominant flow regime appears to be the elongated bubble mode that can persist up to vapor qualities as high as 60-70% in microchannels, followed by annular flow. Flow boiling heat transfer coefficients have been shown experimentally to be dependent on heat flux and saturation pressure while only slightly dependent on mass velocity and vapor quality. Hence, these studies have concluded that nucleate boiling controls evaporation in microchannels. Instead, a recent analytical study has shown that transient evaporation of the thin liquid films surrounding elongated bubbles is the dominant heat transfer mechanism as opposed to nucleate boiling and is able to predict these trends in the experimental data. Newer experimental studies have further shown that there is in fact a significant effect of mass velocity and vapor quality on heat transfer when covering a broader range of conditions, including a sharp peak at low vapor qualities at high heat fluxes. Furthermore, it is concluded that macroscale models are not realistic for predicting flowing boiling coefficients in microchannels as the controlling mechanism is not nucleate boiling nor turbulent convection but is transient thin film evaporation (also, microchannel flows are typically laminar and not turbulent as assumed by macroscopic models). A more advanced three-zone flow boiling model for evaporation of elongated bubbles in microchannels is currently under development that so far qualitatively describes all these trends. Numerous fundamental aspects of two-phase flow and evaporation remain to be better understood and some of these aspects are also discussed

Cáncer de mama

OpenAIRE

Camino Bravo, Ivonne Aracely

2017-01-01

El cáncer de mama es una de las principales causas de muerte entre las mujeres de entre 45-55 años y en las de avanzada edad, incluso está por encima del cáncer de pulmón. Hay diferentes tipos de cáncer según el tamaño, las zonas afectadas y la cantidad de quiste que haya, el más grave de los casos es el CARCIROMA INFLAMATORIO que se da en el 1% de los casos, es muy agresivo y se extiende con mucha rapidez.

Process for separating nitrogen from methane using microchannel process technology

Science.gov (United States)

Tonkovich, Anna Lee [Marysville, OH; Qiu, Dongming [Dublin, OH; Dritz, Terence Andrew [Worthington, OH; Neagle, Paul [Westerville, OH; Litt, Robert Dwayne [Westerville, OH; Arora, Ravi [Dublin, OH; Lamont, Michael Jay [Hilliard, OH; Pagnotto, Kristina M [Cincinnati, OH

2007-07-31

The disclosed invention relates to a process for separating methane or nitrogen from a fluid mixture comprising methane and nitrogen, the process comprising: (A) flowing the fluid mixture into a microchannel separator, the microchannel separator comprising a plurality of process microchannels containing a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the methane or nitrogen is sorbed by the sorption medium, and removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing the methane or nitrogen from the sorption medium and removing the desorbed methane or nitrogen from the microchannel separator. The process is suitable for upgrading methane from coal mines, landfills, and other sub-quality sources.

Condensation in Microchannels

National Research Council Canada - National Science Library

Ameel, Timothy

1999-01-01

.... Evaporators and condensers for meso-scale energy systems will most likely be constructed of microchannels due to the microfabrication constraints that limit most structures to two-dimensional planar geometries...

Laser beam micro-milling of micro-channels in aerospace alloys

CERN Document Server

Ahmed, Naveed; Al-Ahmari, Abdulrahman

2017-01-01

This volume is greatly helpful to micro-machining and laser engineers as it offers obliging guidelines about the micro-channel fabrications through Nd:YAG laser beam micro-milling. The book also demonstrates how the laser beam micro-milling behaves when operating under wet conditions (under water), and explores what are the pros and cons of this hybrid technique. From the predictive mathematical models, the readers can easily estimate the resulting micro-channel size against the desired laser parametric combinations. The book considers micro-channels in three highly important research materials commonly used in aerospace industry: titanium alloy Ti-6Al-4V, nickel alloy Inconel 718 and aluminum alloy AA 2024. Therefore, the book is highly practicable in the fields of micro-channel heat exchangers, micro-channel aerospace turbine blades, micro-channel heat pipes, micro-coolers and micro-channel pulsating heat plates. These are frequently used in various industries such as aerospace, automotive, biomedical and m...

METHODS ADVANCEMENT FOR MILK ANALYSIS: THE MAMA STUDY

Science.gov (United States)

The Methods Advancement for Milk Analysis (MAMA) study was designed by US EPA and CDC investigators to provide data to support the technological and study design needs of the proposed National Children=s Study (NCS). The NCS is a multi-Agency-sponsored study, authorized under the...

Heat transfer and fluid flow in minichannels and microchannels

CERN Document Server

Kandlikar, Satish; Li, Dongqing; Colin, Stephane; King, Michael R

2014-01-01

Heat exchangers with minichannel and microchannel flow passages are becoming increasingly popular due to their ability to remove large heat fluxes under single-phase and two-phase applications. Heat Transfer and Fluid Flow in Minichannels and Microchannels methodically covers gas, liquid, and electrokinetic flows, as well as flow boiling and condensation, in minichannel and microchannel applications. Examining biomedical applications as well, the book is an ideal reference for anyone involved in the design processes of microchannel flow passages in a heat exchanger. Each chapter is accompan

Synthesis of Rh/Macro-Porous Alumina Over Micro-Channel Plate and Its Catalytic Activity Tests for Diesel Reforming.

Science.gov (United States)

Seong, Yeon Baek; Kim, Yong Sul; Park, No-Kuk; Lee, Tae Jin

2015-11-01

Macro-porous Al2O3 as the catalytic support material was synthesized using colloidal polystyrene spheres over a micro-channel plate. The colloidal polystyrene spheres were used as a template for the production of an ordered macro porous material using an alumina nitrate solution as the precursor for Al2O3. The close-packed colloidal crystal array template method was applied to the formulation of ordered macro-porous Al2O3 used as a catalytic support material over a micro-channel plate. The solvent in the mixture solution, which also contained the colloidal polystyrene solution, aluminum nitrate solution and the precursor of the catalytic active materials (Rh), was evaporated in a vacuum oven at 50 degrees C. The ordered polystyrene spheres and aluminum salt of the solid state were deposited over a micro channel plate, and macro-porous Al2O3 was formed after calcination at 600 degrees C to remove the polystyrene spheres. The catalytic activity of the Rh/macro-porous alumina supported over the micro-channel plate was tested for diesel reforming.

Microchannel boiling mechanisms leading to burnout

International Nuclear Information System (INIS)

Landram, C.S.; Riddle, R.A.

1994-01-01

The authors are analyzing the thermal performance of microchannel heat sinks to extend their applied heat loads beyond coolant single-phase limits. This is the first investigation of boiling in the narrow (50-μm) microchannels having typically high-aspect-ratio (of order 10/1) flow cross-sections. The prescription of local, wall-coolant, interfacial, two-phase correlations first required development of a validated, approximate, thermal-model accounting for conjugate heat transfer. The strongest mechanism for heat transfer in two-phase microchannel flow was found to be saturated boiling in a channel region near the heated base. When this region dried out, burnout occurred, both in the computations and in the experiment

Insônia em pacientes com câncer de mama

OpenAIRE

Rafihi-Ferreira,Renatha El; Soares,Maria Rita Zoéga

2012-01-01

A insônia é uma queixa frequente em pacientes com câncer de mama, e suas consequências podem causar impacto na qualidade de vida e no curso da doença. O objetivo deste estudo foi revisar a literatura especializada sobre a relação entre insônia e câncer de mama, abordando definição, prevalência, fatores etiológicos e as consequências da insônia no contexto da neoplasia mamária, bem como os tratamentos para insônia nessa população. A busca da literatura ocorreu nos bancos de dados Scopus, Web o...

Rastreamento do câncer de mama: quais as tendências atuais?

Directory of Open Access Journals (Sweden)

Andréa Pires Souto Damin

2012-07-01

Full Text Available O câncer de mama é a neoplasia maligna mais frequente no mundo. No Brasil, representa a principal causa de morte por câncer em mulheres (1,2. Segundo o INCA (Instituto Nacional do Câncer são esperados 52 casos para 100.000 mulheres em 2012. Porto Alegre tem a maior incidência no país, com estimativa de 125 casos por 100.000 mulheres (2. Nesta edição da Revista do HCPA, um grupo de Minas Gerais avalia o papel da mamografia no rastreamento do câncer de mama. Até o momento, não existe prevenção primária efetiva para o câncer de mama. Como apresenta uma fase subclínica longa, variando entre 2 e 4 anos, a diminuição da mortalidade depende da detecção precoce. A sobrevida da doença em estágios iniciais pode alcançar 98% em 5 anos (1.

Linfoma No Hodgkin Primario de Mama: Reporte de un Caso.

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H. Gámez Oliva

2016-01-01

Full Text Available El linfoma no Hodgkin primario de la mama es una patología poco frecuente, constituye menos del 0,5% de todos los tumores mamarios malignos, debido a que carecen de características propias, tanto clínicas, mamográficas como ultrasonográficas. Es difícil el diagnóstico preoperatorio, la citología mediante BAAF tiene mejor rendimiento que el estudio con material congelado ya que este último tiende a confundirse con el carcinoma. En la actualidad se prefiere el tratamiento con quimioterapia tanto para el tratamiento local como para el regional. Presentamos el caso de un linfoma no Hodgkin primario de la mama en una paciente de 72 años.

Comparison of the automated evaluation of phantom mama in digital and digitalized images

International Nuclear Information System (INIS)

Santana, Priscila do Carmo

2011-01-01

Mammography is an essential tool for diagnosis and early detection of breast cancer if it is provided as a very good quality service. The process of evaluating the quality of radiographic images in general, and mammography in particular, can be much more accurate, practical and fast with the help of computer analysis tools. This work compare the automated methodology for the evaluation of scanned digital images the phantom mama. By applied the DIP method techniques was possible determine geometrical and radiometric images evaluated. The evaluated parameters include circular details of low contrast, contrast ratio, spatial resolution, tumor masses, optical density and background in Phantom Mama scanned and digitized images. The both results of images were evaluated. Through this comparison was possible to demonstrate that this automated methodology is presented as a promising alternative for the reduction or elimination of subjectivity in both types of images, but the Phantom Mama present insufficient parameters for spatial resolution evaluation. (author)

Study of condensation of refrigerants in a micro-channel for development of future compact micro-channel condensers

Science.gov (United States)

Chowdhury, Sourav

2009-12-01

Mini- and micro-channel technology has gained considerable ground in the recent years in industry and is favored due to its several advantages stemming from its high surface to volume ratio and high values of proof pressure it can withstand. Micro-channel technology has paved the way to development of highly compact heat exchangers with low cost and mass penalties. In the present work, the issues related to the sizing of compact micro-channel condensers have been explored. The considered designs encompass both the conventional and MEMS fabrication techniques. In case of MEMS-fabricated micro-channel condenser, wet etching of the micro-channel structures, followed by bonding of two such wafers with silicon nitride layers at the interface was attempted. It was concluded that the silicon nitride bonding requires great care in terms of high degree of surface flatness and absence of roughness and also high degree of surface purity and thus cannot be recommended for mass fabrication. Following this investigation, a carefully prepared experimental setup and test micro-channel with hydraulic diameter 700 mum and aspect ratio 7:1 was fabricated and overall heat transfer and pressure drop aspects of two condensing refrigerants, R134a and R245fa were studied at a variety of test conditions. To the best of author's knowledge, so far no data has been reported in the literature on condensation in such high aspect ratio micro-channels. Most of the published experimental works on condensation of refrigerants are concerning conventional hydraulic diameter channels (> 3mm) and only recently some experimental data has been reported in the sub-millimeter scale channels for which the surface tension and viscosity effects play a dominant role and the effect of gravity is diminished. It is found that both experimental data and empirically-derived correlations tend to under-predict the present data by an average of 25%. The reason for this deviation could be because a high aspect ratio

Staging by tomography: Lung, esophagus, mama and pleural cancer

International Nuclear Information System (INIS)

Gigirey, V.

2012-01-01

This presentation shows images of different types of cancer in the lung, esophagus, mama and pleura. The chest radiography, computed tomography, magnetic resonance and PET CT contribute to detect the morphology, size, location, metastasize, malignant and benign nodules, lymph glands.

Metastização pulmonar de neoplasia da mama

Directory of Open Access Journals (Sweden)

Jorge Dionísio

2002-03-01

Full Text Available RESUMO: Para caracterizar os doentes com metastização pulmonar de neoplasia da mama, procedemos a um estudo retrospectivo dos processos de 129 doentes referenciados à Unidade de Pneumologia entre Julho de 1990 e Janeiro de 2000.Foi considerada a existência de metastização pulmonar em 89 casos.Avaliámos as manifestações clínicas apresentadas, o intervalo de tempo até ao diagnóstico de metastização pulmonar, os aspectos radiológicos, endoscópicos, as terapêuticas efectuadas e a sobrevida.O intervalo médio entre o diagnóstico da neoplasia da mama e o diagnóstico de metastização pulmonar foi de 81,9±5,7 meses. Os sintomas respiratórios foram referidos em 83,1% dos doentes. O padrão radiológico mais comum foi a presença de massas ou nódulos pulmonares (66,3%. Foram observadas 49 com sinais directos de neoplasia na broncofibroscopia. Em 47 os aspectos anatomopatológicos encontrados foram compatíveis com metastização endobrônquica de tumor da mamaO tratamento mais frequentemente utilizado após o diagnóstico de metástase pulmonar foi a quimioterapia, em 60,2% dos casos.Após o diagnóstico de metastização, a sobrevida mediana foi de 20,1 meses, com 63,4% dos doentes vivos ao fim de 1 ano.Nos doentes com carcinoma da mama e suspeita de metastização verificámos um grande intervalo livre entre o diagnóstico do tumor da mama e o aparecimento de metastização. Os sintomas respiratórios tra-duziram a grande frequência de envolvimento endobrônquico. O diagnóstico anatomopatológico de metastização pulmonar foi obtido em 52,8% dos doentes. A terapêutica mais utilizada após diagnóstico de metastização foi a quimioterapia e a sobrevida ao ano foi de 63,4%.REV PORT PNEUMOL 2002; VIII (2: ABSTRACT: We performed a retrospective study of 129 patients observed in Pneumology unit between July 1990 and January 2000 to evaluate the clinical, radiological and endoscopic patterns as well as the clinical evolution of

POSIBLES MECANISMOS DE ACCIÓN BIOLÓGICA DE LA ACTIVIDAD FÍSICA EN EL CÁNCER DE MAMA

Directory of Open Access Journals (Sweden)

Jairo Alejandro Fernández Ortega

2014-11-01

Full Text Available La evidencia científica ha demostrado la importancia de la actividad física como una estrategia efectiva para disminuir el riesgo y la recidiva del cáncer de mama. Sin embargo, hasta el momento no se conocen con precisión los mecanismos de acción biológicos del ejercicio sobre el cáncer de mama. El propósito de este artículo es realizar una revisión sistemática exhaustiva de la literatura e identificar las posibles hipótesis que se plantean de los mecanismos de acción biológicos del ejercicio sobre el cáncer de mama. Se realizó una revisión sistemática de la literatura publicada desde 1990 hasta 2011 sobre los efectos del ejercicio en el cáncer de mama.

Study of different cross-shaped microchannels affecting thermal-bubble-actuated microparticle manipulation

Science.gov (United States)

Li, Weichen; Tsou, Chingfu

2015-10-01

This paper presents a thermal-bubble-actuated microfluidic chip with cross-shaped microchannels for evaluating the effect of different microchannel designs on microparticle manipulation. Four cross-shaped microchannel designs, with orthogonal, misaligned, skewed, and antiskewed types, were proposed in this study. The thermal bubble micropump, which is based on a resistive bulk microheater, was used to drive fluid transportation, and it can be realized using a simple microfabrication process with a silicon-on-isolator wafer. Using commercial COMSOL software, the flow profiles of microfluidics in various cross-shaped microchannels were simulated qualitatively under different pumping pressures. Microbeads, with a diameter of 20 μm, manipulated in four cross-shaped microchannels, were also implemented in this experiment. The results showed that a skewed microchannel design has a higher sorting rate compared with orthogonal, misaligned, and antiskewed microchannels because its flow velocity in the main microchannel is significantly reduced by pumping pressure. Typically, the successful sorting rate for this type of skewed microchannel can reach 30% at a pumping frequency of 100 Hz.

Formation of microchannels from low-temperature plasma-deposited silicon oxynitride

Science.gov (United States)

Matzke, Carolyn M.; Ashby, Carol I. H.; Bridges, Monica M.; Manginell, Ronald P.

2000-01-01

A process for forming one or more fluid microchannels on a substrate is disclosed that is compatible with the formation of integrated circuitry on the substrate. The microchannels can be formed below an upper surface of the substrate, above the upper surface, or both. The microchannels are formed by depositing a covering layer of silicon oxynitride over a mold formed of a sacrificial material such as photoresist which can later be removed. The silicon oxynitride is deposited at a low temperature (.ltoreq.100.degree. C.) and preferably near room temperature using a high-density plasma (e.g. an electron-cyclotron resonance plasma or an inductively-coupled plasma). In some embodiments of the present invention, the microchannels can be completely lined with silicon oxynitride to present a uniform material composition to a fluid therein. The present invention has applications for forming microchannels for use in chromatography and electrophoresis. Additionally, the microchannels can be used for electrokinetic pumping, or for localized or global substrate cooling.

Effect of microchannel structure on the reaction performance of methanol steam reforming

International Nuclear Information System (INIS)

Pan, Minqiang; Wu, Qiuyu; Jiang, Lianbo; Zeng, Dehuai

2015-01-01

Highlights: • Effect of microchannel cross-section and distribution on MSR are investigated. • Microchannel distribution shows much more influence on reaction performance. • SLDR and ELR with rectangular cross-section present better reaction performance. • DLSR and EUU with tooth cross-section have better reaction performance. • Equal-distribution of microchannels present the best reaction performance. - Abstract: Methanol steam reforming inside microchannel reactors is regarded as one of effective methods for supplying hydrogen for fuel cells. Microchannel structure plays an important role on the reaction performance of methanol steam reforming. Parallel and uniform-distributed microchannels with rectangular cross-section are generally adopted. In this work, two kinds of microchannel cross-sections and four kinds of microchannel distributions are selected to investigate the effect of microchannel structure on the reaction performance of methanol steam reforming. The result indicates that microchannel distribution shows much more influences on the reaction performance of methanol steam reforming than the microchannel cross-section. Sparse-distribution in the Left direction and Dense-distribution in the Right direction (SLDR) as well as Equal-distribution in the Left–Right direction (ELR) with rectangular cross-section present relatively good reaction performances, whereas Dense-distribution in the Left direction and Sparse-distribution in the Right direction (DLSR) as well as Equal-distribution in the Upside–Underside direction (EUU) with tooth cross-section have relatively good performances. ELR presents the best reaction performances of methanol steam reforming among all the investigated microchannel structures, whether rectangular or tooth cross-section

Comportamiento del cáncer de mama en la provincia de Cienfuegos. Quinquenio 2007-2011

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Lidia Torres Ajá

2013-09-01

Full Text Available Fundamento: el cáncer de mama representa la primera localización y segunda causa de muerte por tumores malignos en el sexo femenino en Cuba, lo cual ha hecho que sea considerado un problema de salud y una línea priorizada de investigación por parte del Ministerio de Salud Pública. Objetivo: caracterizar el comportamiento del cáncer de mama en la provincia de Cienfuegos en el quinquenio 2007-2011. Métodos: se realizó un estudio descriptivo, prospectivo, del total de pacientes operados de cáncer de mama en la provincia de Cienfuegos durante 5 años, comprendidos desde el 1 de enero de 2007 al 31 de diciembre del 2011. Se analizaron las variables: sexo, edad, mama afectada, localización topográfica, variante histológica, etapa clínica en el momento del diagnóstico, modalidad de biopsia utilizada y técnicas quirúrgicas aplicadas. Para la recolección de los datos se confeccionó un modelo que fue aplicado a cada paciente, además de revisarse las historias clínicas y protocolos biópsicos. Resultados: existen tasas de incidencia altas en este quinquenio. Existe predominio de afectación en pacientes mayores de 50 años y el carcinoma ductal infiltrante es la modalidad más diagnosticada. El 80,6 % de los tumores se diagnosticaron en etapas tempranas. Conclusiones: el cáncer de mama constituye un problema de salud en la provincia de Cienfuegos, con altas tasas de incidencia, y con un 80,6 % de los tumores diagnosticados en etapas curables.

Ansiedad y depresión en mujeres con cáncer de mama en radioterapia: Prevalencia y factores asociados

OpenAIRE

Ornelas-Mejorada,Rosa Elena; Tufiño Tufiño,Mónica Anahí; Sánchez-Sosa,Juan José

2011-01-01

Someterse a radioterapia y padecer los efectos secundarios son situaciones que generan ansiedad y depresión en las mujeres con cáncer de mama. El objetivo fue evaluar la prevalencia de ansiedad y depresión que presentan las mujeres con cáncer de mama en radioterapia y analizar los efectos y las diferencias de variables clínicas y sociodemográficas sobre su malestar psicológico. Participaron 203 mujeres mexicanas con cáncer de mama en estadios 0-III. Para evaluar ansiedad y depresión se utiliz...

Melt analysis of mismatch amplification mutation assays (Melt-MAMA: a functional study of a cost-effective SNP genotyping assay in bacterial models.

Directory of Open Access Journals (Sweden)

Dawn N Birdsell

Full Text Available Single nucleotide polymorphisms (SNPs are abundant in genomes of all species and biologically informative markers extensively used across broad scientific disciplines. Newly identified SNP markers are publicly available at an ever-increasing rate due to advancements in sequencing technologies. Efficient, cost-effective SNP genotyping methods to screen sample populations are in great demand in well-equipped laboratories, but also in developing world situations. Dual Probe TaqMan assays are robust but can be cost-prohibitive and require specialized equipment. The Mismatch Amplification Mutation Assay, coupled with melt analysis (Melt-MAMA, is flexible, efficient and cost-effective. However, Melt-MAMA traditionally suffers from high rates of assay design failures and knowledge gaps on assay robustness and sensitivity. In this study, we identified strategies that improved the success of Melt-MAMA. We examined the performance of 185 Melt-MAMAs across eight different pathogens using various optimization parameters. We evaluated the effects of genome size and %GC content on assay development. When used collectively, specific strategies markedly improved the rate of successful assays at the first design attempt from ~50% to ~80%. We observed that Melt-MAMA accurately genotypes across a broad DNA range (~100 ng to ~0.1 pg. Genomic size and %GC content influence the rate of successful assay design in an independent manner. Finally, we demonstrated the versatility of these assays by the creation of a duplex Melt-MAMA real-time PCR (two SNPs and conversion to a size-based genotyping system, which uses agarose gel electrophoresis. Melt-MAMA is comparable to Dual Probe TaqMan assays in terms of design success rate and accuracy. Although sensitivity is less robust than Dual Probe TaqMan assays, Melt-MAMA is superior in terms of cost-effectiveness, speed of development and versatility. We detail the parameters most important for the successful application of

Avaliação da eficácia de um programa de intervenção multidisciplinar em sobreviventes de cancro da mama

OpenAIRE

Correia, Tânia Alexandra Silva

2015-01-01

Com os avanços que se têm alcançado na deteção precoce e no tratamento do cancro da mama tem-se verificado um aumento no número de sobreviventes de cancro da mama. A intervenção multidisciplinar tem demonstrado a sua eficácia em sobreviventes de cancro da mama. O presente estudo pretende implementar e avaliar um programa de intervenção multidisciplinar, que integra a psicoeducação com a fisioterapia, em mulheres sobreviventes de cancro da mama. A amostra foi constituída por 19 sobreviventes d...

Microfabrication of Microchannels for Fuel Cell Plates

Directory of Open Access Journals (Sweden)

Ho Su Jang

2009-12-01

Full Text Available Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

Replicating the MamaToto Program in Rural Tanzania (IMCHA ...

International Development Research Centre (IDRC) Digital Library (Canada)

This project draws on the low-cost MamaToto (mother-baby) process implemented in Uganda, where substantial gains in maternal and child health were achieved. These gains took place through an approach that strengthened services at health facilities and within communities. This project will implement and evaluate a ...

Fibroadenoma en mama axilar supernumeraria; reporte de un caso

OpenAIRE

M. Nuvia Aliaga, Dra; V. Alvaro Ibarra, Dr.; V. Paulina Neira, Dra.; M. Luis Contreras, Dr.

2010-01-01

Se presenta el caso de una paciente de 41 años portadora de mamas axilares bilaterales que consulta por dolor más masa palpable en una de ellas. La paciente es sometida a resección quirúrgica que mostró que el tumor era un fibroadenoma.

Prevalencia de depresión en pacientes con cáncer de mama. Revisión de la literatura

OpenAIRE

Sagardoy Muniesa, L.; Miguel Romeo, C.; Sebastián Meneses, N.

2013-01-01

1.- INTRODUCCIÓN: La depresión es una sintomatología muy frecuente en los pacientes diagnosticados con cáncer de mama y su tratamiento. Se plantea una revisión de la literatura para analizar la prevalencia de la depresión en personas con cáncer de mama. 2.- METODOS: Revisión sistemática. Bases de datos: EMBASE (1999-2010) PUBMED (1981-2010). Se incluyeron los artículos que relacionaban prevalencia y depresión en cáncer de mama. 3.- RESULTADOS: Se localizaron 49 estudios; sólo 12 cumplieron lo...

Carcinoma in situ dentro de un fibroadenoma de mama: Tres casos clínicos

OpenAIRE

TAPIA N,GRACE; CARRASCO A,GONZALO; CAMUS A,MAURICIO; ODDÓ B,DAVID

2008-01-01

El fibroadenoma (FA) es un tumor frecuente de la mama que se presenta usualmente en la segunda y tercera década de la vida. Los carcinomas de la mama raramente se desarrollan dentro de un FA, existiendo alrededor de 200 casos descritos en la literatura. Nosotros reportamos la presencia de carcinoma ductal in s/fu(CDIS) al interior de un FAen tres pacientes mujeres de 31, 45 y 47 años. La presencia de microcalcificaciones en dos pacientes y la sospecha de un papiloma intraductal en la tercera,...

Localized electric field induced transition and miniaturization of two-phase flow patterns inside microchannels.

Science.gov (United States)

Sharma, Abhinav; Tiwari, Vijeet; Kumar, Vineet; Mandal, Tapas Kumar; Bandyopadhyay, Dipankar

2014-10-01

Strategic application of external electrostatic field on a pressure-driven two-phase flow inside a microchannel can transform the stratified or slug flow patterns into droplets. The localized electrohydrodynamic stress at the interface of the immiscible liquids can engender a liquid-dielectrophoretic deformation, which disrupts the balance of the viscous, capillary, and inertial forces of a pressure-driven flow to engender such flow morphologies. Interestingly, the size, shape, and frequency of the droplets can be tuned by varying the field intensity, location of the electric field, surface properties of the channel or fluids, viscosity ratio of the fluids, and the flow ratio of the phases. Higher field intensity with lower interfacial tension is found to facilitate the oil droplet formation with a higher throughput inside the hydrophilic microchannels. The method is successful in breaking down the regular pressure-driven flow patterns even when the fluid inlets are exchanged in the microchannel. The simulations identify the conditions to develop interesting flow morphologies, such as (i) an array of miniaturized spherical or hemispherical or elongated oil drops in continuous water phase, (ii) "oil-in-water" microemulsion with varying size and shape of oil droplets. The results reported can be of significance in improving the efficiency of multiphase microreactors where the flow patterns composed of droplets are preferred because of the availability of higher interfacial area for reactions or heat and mass exchange. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Static response of deformable microchannels: a comparative modelling study

Science.gov (United States)

Shidhore, Tanmay C.; Christov, Ivan C.

2018-02-01

We present a comparative modelling study of fluid-structure interactions in microchannels. Through a mathematical analysis based on plate theory and the lubrication approximation for low-Reynolds-number flow, we derive models for the flow rate-pressure drop relation for long shallow microchannels with both thin and thick deformable top walls. These relations are tested against full three-dimensional two-way-coupled fluid-structure interaction simulations. Three types of microchannels, representing different elasticity regimes and having been experimentally characterized previously, are chosen as benchmarks for our theory and simulations. Good agreement is found in most cases for the predicted, simulated and measured flow rate-pressure drop relationships. The numerical simulations performed allow us to also carefully examine the deformation profile of the top wall of the microchannel in any cross section, showing good agreement with the theory. Specifically, the prediction that span-wise displacement in a long shallow microchannel decouples from the flow-wise deformation is confirmed, and the predicted scaling of the maximum displacement with the hydrodynamic pressure and the various material and geometric parameters is validated.

Fatores genéticos associados ao câncer de mama masculino: uma revisão de literatura

Directory of Open Access Journals (Sweden)

Nathalia Maria Tomaz Silveira

2016-10-01

Full Text Available O câncer de mama masculino é um quadro neoplásico raro, abrange 1% dos casos de câncer de mama no mundo todo, 1% dos tumores malignos em homens e apresenta incidência anual de 1 por 100.000. Reuniram-se informações acerca da atualidade de estudos relacionados ao caráter genético na patologia abordada, cujo objetivo foi analisar aspectos da predisposição e associação, utilizando 15 artigos originais indexados no período entre janeiro de 2011 a fevereiro de 2016, escritos em inglês e espanhol, com delineamento experimental ou observacional, utilizando os descritores câncer de mama masculino, tratamento do câncer, câncer de mama e fator genético do câncer de mama, assim como suas traduções em inglês male breast cancer, cancer treatment, breast cancer e genetic factors. Discutiu-se principalmente a influência genética na ocorrência do câncer de mama masculino, como alterações em genes supressores BRCA, relações com o ponto de checagem CHECK2, histórico familiar e ligações com a síndrome de Klinefelter, entre outros fatores. Aspectos ambientais também são sugeridos por parte da literatura na manifestação clínica da neoplasia, porém com menores ênfases conclusivas. Apesar da literatura sobre o tema ainda necessitar de crescimento e aprofundamento, observaram-se reafirmações científicas sobre a importância da influência genética, sobretudo do BRCA 2, além de confirmações quanto a multifatoriedade da neoplasia.

Microchannel plate assembly parameters with micron gaps

International Nuclear Information System (INIS)

Demchenkova, A.A.

1987-01-01

Performance of chevron microchannel plate assembly with 5 and 15 μm gaps between them has been investigated. The assembly is placed into a vacuum chamber under pressure -6 Torr and irradiated by neutral He and Ar atom beams with 1.5 and 3 keV energies as well as by ultraviolet photons with 147 nm wave length. Dependence of the gain and amplitude resolution on power voltage in plates are measured. The results obtained have shown that microchannel plates permit to obtain the gain up to 3x10 7 and amplitude resolution up to 30% when detecting both atomic particles and ultraviolet photons. The assembly can be effectively used in those cases when it is necessary to use microchannel plates with curved channels

Material Selection for Microchannel Heatsink: Conjugate Heat Transfer Simulation

Science.gov (United States)

Uday Kumar, A.; Javed, Arshad; Dubey, Satish K.

2018-04-01

Heat dissipation during the operation of electronic devices causes rise in temperature, which demands an effective thermal management for their performance, life and reliability. Single phase liquid cooling in microchannels is an effective and proven technology for electronics cooling. However, due to the ongoing trends of miniaturization and developments in the microelectronics technology, the future needs of heat flux dissipation rate are expected to rise to 1 kW/cm2. Air cooled systems are unable to meet this demand. Hence, liquid cooled heatsinks are preferred. This paper presents conjugate heat transfer simulation of single phase flow in microchannels with application to electronic cooling. The numerical model is simulated for different materials: copper, aluminium and silicon as solid and water as liquid coolant. The performances of microchannel heatsink are analysed for mass flow rate range of 20-40 ml/min. The investigation has been carried out on same size of electronic chip and heat flux in order to have comparative study of different materials. This paper is divided into two sections: fabrication techniques and numerical simulation for different materials. In the first part, a brief discussion of fabrication techniques of microchannel heatsink have been presented. The second section presents conjugate heat transfer simulation and parametric investigation for different material microchannel heatsink. The presented study and findings are useful for selection of materials for microchannel heatsink.

Microchannel plate photodetectors

International Nuclear Information System (INIS)

Majka, R.

1977-01-01

A review is given the status of development work on photodetectors using microchannel plates (MCP) as the electron gain element. Projections are made and opinions are presented on what might be available in the next few years. Several uses for these devices at ISABELLE are mentioned

Fibroadenoma en mama axilar supernumeraria; reporte de un caso

Directory of Open Access Journals (Sweden)

M. Nuvia Aliaga, Dra

2010-03-01

Full Text Available Se presenta el caso de una paciente de 41 años portadora de mamas axilares bilaterales que consulta por dolor más masa palpable en una de ellas. La paciente es sometida a resección quirúrgica que mostró que el tumor era un fibroadenoma.

Avaliação do tempo para acesso ao tratamento do câncer de mama no Distrito Federal

OpenAIRE

Barros, Ângela Ferreira [UNESP

2011-01-01

A alta taxa de mortalidade do câncer de mama em países em desenvolvimento é associada à falta de programas de detecção precoce, ao retardo no diagnóstico e tratamento, bem como às dificuldades para acesso aos serviços de saúde. O objetivo desse estudo foi identificar artigos que associaram o retardo no diagnóstico e tratamento com a evolução do câncer de mama, verificar os fatores associados ao atraso e apontar sugestões para minimizar o atraso no diagnóstico e tratamento do câncer de mama. F...

Detector array and method

International Nuclear Information System (INIS)

Timothy, J.G.; Bybee, R.L.

1978-01-01

A detector array and method are described in which sets of electrode elements are provided. Each set consists of a number of linear extending parallel electrodes. The sets of electrode elements are disposed at an angle (preferably orthogonal) with respect to one another so that the individual elements intersect and overlap individual elements of the other sets. Electrical insulation is provided between the overlapping elements. The detector array is exposed to a source of charged particles which in accordance with one embodiment comprise electrons derived from a microchannel array plate exposed to photons. Amplifier and discriminator means are provided for each individual electrode element. Detection means are provided to sense pulses on individual electrode elements in the sets, with coincidence of pulses on individual intersecting electrode elements being indicative of charged particle impact at the intersection of the elements. Electronic readout means provide an indication of coincident events and the location where the charged particle or particles impacted. Display means are provided for generating appropriate displays representative of the intensity and locaton of charged particles impacting on the detector array

Numerical Investigation of Effect of Surface Roughness in a Microchannel

Energy Technology Data Exchange (ETDEWEB)

Shin, Myung Seob; Byun, Sung Jun; Yoon, Joon Yong [Hanyang University, Seoul (Korea, Republic of)

2010-05-15

In this paper, lattice Boltzmann method(LBM) results for a laminar flow in a microchannel with rough surface are presented. The surface roughness is modeled as an array of rectangular modules placed on the top and bottom surface of a parallel-plate channel. The effects of relative surface roughness, roughness distribution, and roughness size are presented in terms of the Poiseuille number. The roughness distribution characterized by the ratio of the roughness height to the spacing between the modules has a negligible effect on the flow and friction factors. Finally, a significant increase in the Poiseuille number is observed when the surface roughness is considered, and the effects of roughness on the microflow field mainly depend on the surface roughness.

CW-laser induced microchannels in dye-polymethacrylic acid films

OpenAIRE

M.A. Camacho-López

2007-01-01

In this work we report on the formation of microchannels on dye-polymethacrylic acid films using a cw-laser. A focalized beam of a He-Ne laser (632.8 nm emission line) was used to form microchannels on the films. It was found that there exists a laser power density threshold for a pit formation that depends on the dye concentration. The dimensions of the laser-induced channels are dependent on the laser power density. Microchannel formation in the transparent polymethacrylic acid films was no...

Scanning Microscopes Using X Rays and Microchannels

Science.gov (United States)

Wang, Yu

2003-01-01

Scanning microscopes that would be based on microchannel filters and advanced electronic image sensors and that utilize x-ray illumination have been proposed. Because the finest resolution attainable in a microscope is determined by the wavelength of the illumination, the xray illumination in the proposed microscopes would make it possible, in principle, to achieve resolutions of the order of nanometers about a thousand times as fine as the resolution of a visible-light microscope. Heretofore, it has been necessary to use scanning electron microscopes to obtain such fine resolution. In comparison with scanning electron microscopes, the proposed microscopes would likely be smaller, less massive, and less expensive. Moreover, unlike in scanning electron microscopes, it would not be necessary to place specimens under vacuum. The proposed microscopes are closely related to the ones described in several prior NASA Tech Briefs articles; namely, Miniature Microscope Without Lenses (NPO-20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43; and Reflective Variants of Miniature Microscope Without Lenses (NPO-20610), NASA Tech Briefs, Vol. 26, No. 9 (September 2002) page 6a. In all of these microscopes, the basic principle of design and operation is the same: The focusing optics of a conventional visible-light microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. A microchannel plate containing parallel, microscopic-cross-section holes much longer than they are wide is placed between a specimen and an image sensor, which is typically the CCD. The microchannel plate must be made of a material that absorbs the illuminating radiation reflected or scattered from the specimen. The microchannels must be positioned and dimensioned so that each one is registered with a pixel on the image sensor. Because most of the radiation incident on the microchannel walls becomes absorbed, the radiation that reaches the

Determinación de células tumorales circulantes y estudio molecular de ganglio centinela en carcinoma precoz de mama

OpenAIRE

Pérez Quintanilla, Almudena

2013-01-01

El cáncer de mama es un problema sanitario y social de primera magnitud en todo el mundo, a pesar de los avances significativos en su diagnóstico y tratamiento. La principal causa de muerte relativa al cáncer de mama es la metástasis. Esta última es el resultado de diversos procesos al final de los cuales la célula tumoral es capaz de sobrevivir en órganos a distancia. En la actualidad un gran porcentaje de las neoplasias de mama se diagnostican en estadios operables y, de ellas, sólo el 24% ...

Mama na Mtoto: Barriers and enablers to gender, equity and scale ...

International Development Research Centre (IDRC) Digital Library (Canada)

Mama na Mtoto: Barriers and enablers to gender, equity and scale-up in Tanzania ... Call for new OWSD Fellowships for Early Career Women Scientists now open ... conference of McGill's Institute for the Study of International Development.

Ansiedad, resiliencia e inteligencia emocional percibida en mujeres con cáncer de mama

OpenAIRE

García-Maroto Fernández, Sagrario

2016-01-01

Introducción. En el presente trabajo de investigación se ha estudiado la ansiedad, la resiliencia y la inteligencia emocional percibida en un grupo de mujeres con cáncer de mama y otro grupo de mujeres sin la enfermedad. Así mismo, se ha realizado el diseño, la aplicación y la evaluación de un programa de inteligencia emocional en un grupo de mujeres con cáncer de mama. - Contenido de la investigación. El marco teórico se centra en los constructos principales de estudio, ansiedad, resilien...

Experimental investigation of heat transfer performance for a novel microchannel heat sink

International Nuclear Information System (INIS)

Wang, Y; Ding, G-F

2008-01-01

We demonstrated a novel microchannel heat sink with a high local heat transfer efficiency contributed by a complicated microchannel system, which comprises parallel longitudinal microchannels etched in a silicon substrate and transverse microchannels electroplated on a copper heat spreader. The thermal boundary layer develops in transverse microchannels. Meanwhile, the heat transfer area is increased compared with the conventional microchannel heat sink only having parallel longitudinal microchannels. Both benefits yield high local heat transfer efficiency and enhance the overall heat transfer, which is attractive for the cooling of high heat flux electronic devices. Infrared tests show the temperature distribution in the test objects. The effects of flow rate and heat flux levels on heat transfer characteristics are presented. A uniform temperature distribution is obtained through the heating area. The reference temperatures decrease with the increasing flow rate from 0.64 ml min −1 to 6.79 ml min −1 for a constant heat flux of 10.4 W cm −2 . A heat flux of 18.9 W cm −2 is attained at a flow rate of 6.79 ml min −1 for assuring the maximum temperature of the microchannel heat sink less than the maximum working temperature of electronic devices

Study on Boiling Heat Transfer Phenomenon in Micro-channels

Energy Technology Data Exchange (ETDEWEB)

Jeong, Namgyun [Inha Technical College, Incheon (Korea, Republic of)

2017-09-15

Recently, efficient heat dissipation has become necessary because of the miniaturization of devices, and research on boiling on micro-channels has attracted attention. However, in the case of micro-channels, the friction coefficient and heat transfer characteristics are different from those in macro-channels. This leads to large errors in the micro scale results, when compared to correlations derived from the macro scale. In addition, due to the complexity of the mechanism, the boiling phenomenon in micro-channels cannot be approached only by experimental and theoretical methods. Therefore, numerical methods should be utilized as well, to supplement these methods. However, most numerical studies have been conducted on macro-channels. In this study, we applied the lattice Boltzmann method, proposed as an alternative numerical tool to simulate the boiling phenomenon in the micro-channel, and predicted the bubble growth process in the channel.

A review on the analysis and experiment of fluid flow and mixing in micro-channels

International Nuclear Information System (INIS)

Kang, Sang Mo; Suh, Yong Kweon; Jayaraj, Simon

2007-01-01

The studies with respect to micro-channels and micro-mixers are expanding in many dimensions. Most significant area of micro-mixer study is the flow analysis in various micro-channel configurations. The flow phenomena in microchannel devices are quite different from that of the macro-scale devices. An attempt is made here to review the important recent literature available in the area of micro-channel flow analysis and mixing. The topics covered include the physics of flow in micro-channels and integrated simulation of the micro-channel flow. Also, the flow control models and electro-kinetically driven micro-channel flows are dealt in detail. A survey of important numerical methods, which are currently popular for micro-channel flow analysis, is carried out. Different options for mixing in microchannels are provided, in sufficient detail

Enabling Microliquid Chromatography by Microbead Packing of Microchannels

Science.gov (United States)

Balvin, Manuel; Zheng, Yun

2014-01-01

The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid

Impedance biosensor based on interdigitated electrode array for detection of E.coli O157:H7 in food products

Science.gov (United States)

Ghosh Dastider, Shibajyoti; Barizuddin, Syed; Dweik, Majed; Almasri, Mahmoud F.

2012-05-01

An impedance biosensor was designed, fabricated and tested for detection of viable Escherichia coli O157:H7 in food samples. This device consists of interdigitated microelectrode array (IDEA) fabricated using thin layer of sputtered gold, embedded under a polydimethylsiloxane (PDMS) microchannel. The array of electrodes is designed to detect viable EColi in different food products. The active surface area of the detection array was modified using goat anti-E.coli polyclonal IgG antibody. Contaminated food samples were tested by infusing the supernatant containing bacteria over the IDEA's, through the microchannel. Antibody-antigen binding on the electrodes results in impedance change. Four serial concentrations of E.coli contaminated food samples (3x102 CFUmL-1 to 3x105 CFUmL-1) were tested. The biosensor successfully detected the E.coli samples, with the lower detection limit being 3x103 CFUmL-1 (up to 3cells/μl). Comparing the test results with an IDEA impedance biosensor without microchannel (published elsewhere) indicates that this biosensor have two order of magnitude times higher sensitivity. The proposed biosensor provides qualitative and quantitative detection, and potentially could be used for detection of other type of bacteria by immobilizing the specific type of antibody.

Aspectos Psicosociales Relacionados con el TEPT en Pacientes con Cáncer de Mama

OpenAIRE

Hernández Moreno, Fresia Paloma; Landero Hernández, René

2015-01-01

El objetivo del estudio fue analizar la relación del estrés, la depresión y las estrategias de afrontamiento con el Trastorno de Estrés Postraumático (TEPT) en una muestra de pacientes con cáncer de mama. Se realizó con una muestra no probabilística de 52 mujeres con cáncer de mama. Se encontró una relación entre TEPT y estrés (r= .344, p= .014), TEPT y depresión (rs=.346, p= .013). El TEPT correlacionó con evitación cognitiva (r= .437, p= .001), TEPT y desesperanza (rs= .437, p= .001) y TEPT...

Transient response of nonideal ion-selective microchannel-nanochannel devices

Science.gov (United States)

Leibowitz, Neta; Schiffbauer, Jarrod; Park, Sinwook; Yossifon, Gilad

2018-04-01

We report evidence of variation in ion selectivity of a fabricated microchannel-nanochannel device resulting in the appearance of a distinct local maximum in the overlimiting chronopotentiometric response. In this system consisting of shallow microchannels joined by a nanochannel, viscous shear at the microchannel walls suppresses the electro-osmotic instability and prevents any associated contribution to the nonmonotonic response. Thus, this response is primarily electrodiffusive. Numerical simulations indicate that concentration polarization develops not only within the microchannel but also within the nanochannel itself, with a local voltage maximum in the chronopotentiometric response correlated with interfacial depletion and having the classic i-2 Sands time dependence. Furthermore, the occurrence of the local maxima is correlated with the change in selectivity due to internal concentration polarization. Understanding the transient nonideal permselective response is essential for obtaining fundamental insight and for optimizing efficient operation of practical fabricated nanofluidic and membrane devices.

Periodic flow patterns of the magnetic fluid in microchannel

International Nuclear Information System (INIS)

Chang, C.-W.; Cheng, Y.-T.; Tsai, C.-Y.; Chien, J.-H.; Wang, P.-Y.; Chen, P.-H.

2007-01-01

In this study, of interests are the periodic flow patterns of the oil-based magnetic fluid in microchannels. A microfluidic chip is made of poly-dimethylsiloxane (PDMS) and contains cross-shape microchannels. The microchannels are 1000 μm in width and 200 μm in depth. A syringe pump was used to drive the fluids. Periodic flow patterns were seen and the slugs of magnetic fluid and DI water were generated. The operating factors discussed in the present work are the flow rates and the magnetic field. The frequency of generation of the slugs increases with increase in the flow rates. Besides, by settling the permanent magnet around the microchannel, the periods of the slug generation are changed. Different positions of the magnet lead to different periods for generating the slugs. By adjusting operating conditions, to control the frequency and the volume of the slugs is practical

Surface roughness influences on the behaviour of flow inside microchannels

Science.gov (United States)

Farias, M. H.; Castro, C. S.; Garcia, D. A.; Henrique, J. S.

2018-03-01

This work discusses influence of the surface roughness on the behavior of liquids flowing inside microchannels. By measuring the flow profile using the micro-PIV technique, the flow of water inside two rectangular microchannels of different wall roughness and in a circular smooth microchannel was studied. Comparisons were made among the experimental results, showing that a metrological approach concerning surface characteristics of microdevices is required to ensure reliability of the measurements for flow analyses in microfluidic processes.

Study of a high gain microchannel plate photomultiplier having low statistical gain fluctuations

International Nuclear Information System (INIS)

Audier, M.

1980-12-01

A new photomultiplier configuration which synthesizes the performances of several models is proposed. The principles of microchannel plate photomultipliers are reviewed. The physical phenomena which limit the electron multiplication process in a microchannel and the detection efficiency of the microchannel plates are investigated. The operation of a herring-bone pattern device and of a system of two microchannel plate photomultipliers are described and characterized [fr

Feminine Melancholia in Gloria Naylor‟s Mama Day : A Kristevan ...

African Journals Online (AJOL)

This paper investigates Gloria Naylor's Mama Day with the intention of identifying the behavioural traits in the major protagonists of the narrative that establish them as victims of 'melancholia'. The paper is a psychoanalytic critical reading of the novel in which Julia Kristeva's postulations are utilized in determining the ...

Carcinoma de mama: novos conceitos na classificação Breast cancer: new concepts in classification

Directory of Open Access Journals (Sweden)

Daniella Serafin Couto Vieira

2008-01-01

Full Text Available O carcinoma de mama é a neoplasia maligna mais comum em mulheres. Estudos moleculares do carcinoma de mama, baseados na identificação do perfil de expressão gênica por meio do cDNA microarray, permitiram definir pelo menos cinco sub-grupos distintos: luminal A, luminal B, superexpressão do HER2, basal e normal breast-like. A técnica de tissue microarray (TMA, descrita pela primeira vez em 1998, permitiu estudar, em várias amostras de carcinoma, os perfis de expressão protéica de diferentes neoplasias. No carcinoma de mama, os TMAs têm sido utilizados para validar os achados dos estudos preliminares, identificando, desta forma, os novos subtipos fenotípicos do carcinoma de mama. Dentre os subtipos classicamente descritos, o grupo basal constitui um dos mais intrigantes subtipos tumorais e é freqüentemente associado com pior prognóstico e ausência de alvos terapêuticos definidos. A classificação histopatológica do carcinoma de mama tem pobre valor preditivo. Portanto, a associação entre o diagnóstico histológico com técnicas moleculares nos laboratórios de anatomia patológica, por meio do estudo imunoistoquímico, pode determinar o perfil molecular do carcinoma de mama, buscando melhorar a resposta terapêutica. Este estudo visou resumir os mais recentes conhecimentos em que se baseiam os novos conceitos da classificação do carcinoma de mama.Breast cancer is the principal cause of death from cancer in women. Molecular studies of breast cancer, based in the identification of the molecular profiling techniques through cDNA microarray, had allowed defining at least five distinct sub-group: luminal A, luminal B, HER-2-overexpression, basal and " normal" type breast-like. The technique of tissue microarrays (TMA, described for the first time in 1998, allows to study, in some samples of breast cancer, distinguished by differences in their gene expression patterns, which provide a distinctive molecular portrait for each tumor

Numerical Simulation and Analysis of Gas-Liquid Flow in a T-Junction Microchannel

Directory of Open Access Journals (Sweden)

Hongtruong Pham

2012-01-01

Full Text Available Gas-liquid flow in microchannels is widely used in biomedicine, nanotech, sewage treatment, and so forth. Particularly, owing to the high qualities of the microbubbles and spheres produced in microchannels, it has a great potential to be used in ultrasound imaging and controlled drug release areas; therefore, gas-liquid flow in microchannels has been the focus in recent years. In this paper, numerical simulation of gas-liquid flows in a T-junction microchannel was carried out with computational fluid dynamics (CFD software FLUENT and the Volume-of-Fluid (VOF model. The distribution of velocity, pressure, and phase of fluid in the microchannel was obtained, the pressure distribution along the channel walls was analyzed in order to give a better understanding on the formation of microbubbles in the T-junction microchannel.

Critical heat flux in flow boiling in microchannels

CERN Document Server

Saha, Sujoy Kumar

2015-01-01

This Brief concerns the important problem of critical heat flux in flow boiling in microchannels. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,” by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

Axisymmetric polydimethysiloxane microchannels for in vitro hemodynamic studies

International Nuclear Information System (INIS)

Lima, Rui; Oliveira, Monica S N; Ishikawa, Takuji; Kaji, Hirokazu; Nishizawa, Matsuhiko; Tanaka, Shuji; Yamaguchi, Takami

2009-01-01

The current microdevices used for biomedical research are often manufactured using microelectromechanical systems (MEMS) technology. Although it is possible to fabricate precise and reproducible rectangular microchannels using soft lithography techniques, this kind of geometry may not reflect the actual physiology of the microcirculation. Here, we present a simple method to fabricate circular polydimethysiloxane (PDMS) microchannels aiming to mimic an in vivo microvascular environment and suitable for state-of-the-art microscale flow visualization techniques, such as confocal μPIV/PTV. By using a confocal μPTV system individual red blood cells (RBCs) were successfully tracked trough a 75 μm circular PDMS microchannel. The results show that RBC lateral dispersion increases with the volume fraction of RBCs in the solution, i.e. with the hematocrit.

NASA's Platform for Cross-Disciplinary Microchannel Research

Science.gov (United States)

Son, Sang Young; Spearing, Scott; Allen, Jeffrey; Monaco, Lisa A.

2003-01-01

A team from the Structural Biology group located at the NASA Marshall Space Flight Center in Huntsville, Alabama is developing a platform suitable for cross-disciplinary microchannel research. The original objective of this engineering development effort was to deliver a multi-user flight-certified facility for iterative investigations of protein crystal growth; that is, Iterative Biological Crystallization (IBC). However, the unique capabilities of this facility are not limited to the low-gravity structural biology research community. Microchannel-based research in a number of other areas may be greatly accelerated through use of this facility. In particular, the potential for gas-liquid flow investigations and cellular biological research utilizing the exceptional pressure control and simplified coupling to macroscale diagnostics inherent in the IBC facility will be discussed. In conclusion, the opportunities for research-specific modifications to the microchannel configuration, control, and diagnostics will be discussed.

Non-Newtonian fluid structure interaction in flexible biomimetic microchannels

Science.gov (United States)

Kiran, M.; Dasgupta, Sunando; Chakraborty, Suman

2017-11-01

To investigate the complex fluid structure interactions in a physiologically relevant microchannel with deformable wall and non-Newtonian fluid that flows within it, we fabricated cylindrical microchannels of various softness out of PDMS. Experiments to measure the transient pressure drop across the channel were carried out with high sampling frequencies to capture the intricate flow physics. In particular, we showed that the waveforms varies greatly for each of the non-Newtonian and Newtonian cases for both non-deformable and deformable microchannels in terms of the peak amplitude, r.m.s amplitude and the crest factor. In addition, we carried out frequency sweep experiments to evaluate the frequency response of the system. We believe that these results will aid in the design of polymer based microfluidic phantoms for arterial FSI studies, and in particular for studying blood analog fluids in cylindrical microchannels as well as developing frequency specific Lab-on-chip systems for medical diagnostics.

Microchannel electron multiplier

International Nuclear Information System (INIS)

Beranek, I.; Janousek, L.; Vitovsky, O.

1981-01-01

A microchannel electron multiplier is described for detecting low levels of alpha, beta, soft X-ray and UV radiations. It consists of a glass tube or a system of tubes of various shapes made of common technological glass. The inner tube surface is provided with an active coat with photoemitter and secondary emitter properties. (B.S.)

Integrated microchannel cooling in a three dimensional integrated circuit: A thermal management

Directory of Open Access Journals (Sweden)

Wang Kang-Jia

2016-01-01

Full Text Available Microchannel cooling is a promising technology for solving the three-dimensional integrated circuit thermal problems. However, the relationship between the microchannel cooling parameters and thermal behavior of the three dimensional integrated circuit is complex and difficult to understand. In this paper, we perform a detailed evaluation of the influence of the microchannel structure and the parameters of the cooling liquid on steady-state temperature profiles. The results presented in this paper are expected to aid in the development of thermal design guidelines for three dimensional integrated circuit with microchannel cooling.

Silicon-micromachined microchannel plates

CERN Document Server

Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

Thermal performance of nanofluid flow in microchannels

Energy Technology Data Exchange (ETDEWEB)

Li Jie [Department of Mechanical and Aerospace Engineering, University of North Carolina, Campus Box 7910, Broungton Hall 4160, Raleigh, NC 27695-7910 (United States); Kleinstreuer, Clement [Department of Mechanical and Aerospace Engineering, University of North Carolina, Campus Box 7910, Broungton Hall 4160, Raleigh, NC 27695-7910 (United States)], E-mail: ck@eos.ncsu.edu

2008-08-15

Two effective thermal conductivity models for nanofluids were compared in detail, where the new KKL (Koo-Kleinstreuer-Li) model, based on Brownian motion induced micro-mixing, achieved good agreements with the currently available experimental data sets. Employing the commercial Navier-Stokes solver CFX-10 (Ansys Inc., Canonsburg, PA) and user-supplied pre- and post-processing software, the thermal performance of nanofluid flow in a trapezoidal microchannel was analyzed using pure water as well as a nanofluid, i.e., CuO-water, with volume fractions of 1% and 4% CuO-particles with d{sub p} = 28.6 nm. The results show that nanofluids do measurably enhance the thermal performance of microchannel mixture flow with a small increase in pumping power. Specifically, the thermal performance increases with volume fraction; but, the extra pressure drop, or pumping power, will somewhat decrease the beneficial effects. Microchannel heat sinks with nanofluids are expected to be good candidates for the next generation of cooling devices.

Dynamic Modelling of the DEP Controlled Boiling in a Microchannel

Science.gov (United States)

Lackowski, Marcin; Kwidzinski, Roman

2018-04-01

The paper presents theoretical analysis of flow dynamics in a heated microchannel in which flow rate may be controlled by dielectrophoretic (DEP) forces. Proposed model equations were derived in terms of lumped parameters characterising the system comprising of DEP controller and the microchannel. In result, an equation for liquid height of rise in the controller was obtained from momentum balances in the two elements of the considered system. In the model, the boiling process in the heated section of microchannel is taken into account through a pressure drop, which is a function of flow rate and uniform heat flux. Presented calculation results show that the DEP forces influence mainly the flow rate in the microchannel. In this way, by proper modulation of voltage applied to the DEP controller, it is possible to lower the frequency of Ledinegg instabilities.

Slip flow through a converging microchannel: experiments and 3D simulations

International Nuclear Information System (INIS)

Varade, Vijay; Agrawal, Amit; Pradeep, A M

2015-01-01

An experimental and 3D numerical study of gaseous slip flow through a converging microchannel is presented in this paper. The measurements reported are with nitrogen gas flowing through the microchannel with convergence angles (4°, 8° and 12°), hydraulic diameters (118, 147 and 177 µm) and lengths (10, 20 and 30 mm). The measurements cover the entire slip flow regime and a part of the continuum and transition regimes (the Knudsen number is between 0.0004 and 0.14); the flow is laminar (the Reynolds number is between 0.5 and 1015). The static pressure drop is measured for various mass flow rates. The overall pressure drop increases with a decrease in the convergence angle and has a relatively large contribution of the viscous component. The numerical solutions of the Navier–Stokes equations with Maxwell’s slip boundary condition explore two different flow behaviors: uniform centerline velocity with linear pressure variation in the initial and the middle part of the microchannel and flow acceleration with nonlinear pressure variation in the last part of the microchannel. The centerline velocity and the wall shear stress increase with a decrease in the convergence angle. The concept of a characteristic length scale for a converging microchannel is also explored. The location of the characteristic length is a function of the Knudsen number and approaches the microchannel outlet with rarefaction. These results on gaseous slip flow through converging microchannels are observed to be considerably different than continuum flow. (paper)

Acoustophoretic Synchronization of Mammalian Cells in Microchannels

DEFF Research Database (Denmark)

Thévoz, P.; Adams, J.D.; Shea, H.

2010-01-01

We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel to selec......We report the first use of ultrasonic standing waves to achieve cell cycle phase synchronization in mammalian cells in a high-throughput and reagent-free manner. The acoustophoretic cell synchronization (ACS) device utilizes volume-dependent acoustic radiation force within a microchannel...

Streaming potential of superhydrophobic microchannels.

Science.gov (United States)

Park, Hung Mok; Kim, Damoa; Kim, Se Young

2017-03-01

For the purpose of gaining larger streaming potential, it has been suggested to employ superhydrophobic microchannels with a large velocity slip. There are two kinds of superhydrophobic surfaces, one having a smooth wall with a large Navier slip coefficient caused by the hydrophobicity of the wall material, and the other having a periodic array of no- shear slots of air pockets embedded in a nonslip wall. The electrokinetic flows over these two superhydrophobic surfaces are modelled using the Navier-Stokes equation and convection-diffusion equations of the ionic species. The Navier slip coefficient of the first kind surfaces and the no-shear slot ratio of the second kind surfaces are similar in the sense that the volumetric flow rate increases as these parameter values increase. However, although the streaming potential increases monotonically with respect to the Navier slip coefficient, it reaches a maximum and afterward decreases as the no-shear ratio increases. The results of the present investigation imply that the characterization of superhydrophobic surfaces employing only the measurement of volumetric flow rate against pressure drop is not appropriate and the fine structure of the superhydrophobic surfaces must be verified before predicting the streaming potential and electrokinetic flows accurately. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silicon-micromachined microchannel plates

International Nuclear Information System (INIS)

Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

Retorno al trabajo tras cáncer de mama

Directory of Open Access Journals (Sweden)

Araceli López-Guillén García

Full Text Available Resumen El cáncer de mama frecuentemente es causa de largos procesos de baja. La duración media de las bajas por cáncer de mama es de unos 320 días, estando entre los tres procesos principales que causan bajas de más de 365 días junto con la lumbalgia y el trastorno ansioso depresivo. Cada año se producen 26.000 casos nuevos en España de los que en su mayoría se producen en plena edad laboral. La supervivencia a los cinco años entre mujeres de 30 a 60 años es del 86%. El cáncer de mama es la segunda causa de inicio de expedientes de incapacidad permanente a los doce meses, tras la lumbalgia. Sólo el 53% retomará el trabajo. El retorno al trabajo se vuelve dificultoso tanto por la intensidad y pauta espaciada de los tratamientos, como por la afectación de la calidad de vida, como por la ausencia prolongada del trabajo. Influyendo factores personales de la trabajadora, unos por ella misma, otros ligados al cáncer y su evolución, y factores laborales ligados al tipo de trabajo, riesgos, condiciones y exigencias del mismo y otros factores del mercado de trabajo; que todos ellos considerados no siempre hacen que la vuelta al trabajo sea posible. Material y método: Se han revisado hasta octubre de 2016 las siguientes bases de datos bibliográficas: SciELO, y PUBMED. Así como la Bibliografía y documentos de consulta citados en la misma. Conclusiones: Es preciso facilitar el retorno al trabajo, en especial de aquellos casos más complicados que han precisado de largas bajas pero aun así ya están curados o con una mejoría que permite trabajar. Ante el fenómeno del cáncer de mama y su impacte incapacitante, es preciso conocer el mismo con certeza por lo que se hace necesario la realización urgente del Mapa de Incapacidad en España. Para evitar controversias entre el alta médica para trabajar y la no aptitud para el trabajo debe de institucionalizarse el uso de la Ficha de Valoración Ocupacional. Ante la toma de decisiones es

Cirurgia conservadora no câncer de mama Breast-conserving surgery for breast cancer

Directory of Open Access Journals (Sweden)

Daniel Guimarães Tiezzi

2007-08-01

Full Text Available O tratamento cirúrgico do câncer de mama sofreu expressivas mudanças nas últimas décadas. A cirurgia conservadora é o tratamento padrão para o câncer de mama em estádio inicial. Com a implementação dos programas de rastreamento e o uso emergente de tratamento sistêmico neoadjuvante, um crescente número de pacientes está sendo considerado elegível para o tratamento conservador. No entanto, uma série de fatores importantes merecem ser considerados no planejamento terapêutico destas pacientes. Esta revisão fornece uma visão geral da metodologia cirúrgica no tratamento conservador do carcinoma da mama.The surgical strategy for breast cancer treatment has changed considerably over the last decade. The breast conserving surgery (BCS is the standard treatment for early stage breast cancer nowadays. With the current population breast cancer screening programs and the emerging use of systemic neoadjuvant therapy, an increasing number of patients have been eligible to BCS. However, several specific factors must be considered for the therapeutic planning for these patients. This review provides a surgical methodology overview for the BCS in breast carcinoma.

Resolving Overlimiting Current Mechanisms in Microchannel-Nanochannel Interface Devices

Science.gov (United States)

Yossifon, Gilad; Leibowitz, Neta; Liel, Uri; Schiffbauer, Jarrod; Park, Sinwook

2015-11-01

We present results demonstrating the space charge-mediated transition between classical, diffusion-limited current and surface-conduction dominant over-limiting currents in a shallow micro-nanochannel device. The extended space charge layer develops at the depleted micro-nanochannel entrance at high current and is correlated with a distinctive maximum in the dc resistance. Experimental results for a shallow surface-conduction dominated system are compared with theoretical models, allowing estimates of the effective surface charge at high voltage to be obtained. Further, we extend the study to microchannels of moderate to large depths where the role of various electro-convection mechanisms becomes dominant. In particular, electro-osmotic of the second kind and electro-osmotic instability (EOI) which competes each other at geometrically heterogeneous (e.g. undulated nanoslot interface, array of nanoslots) nanoslot devices. Also, these effects are also shown to be strongly modulated by the non-ideal permselectivity of the nanochannel.

Influence of sinusoidal flow on the thermal and hydraulic performance of microchannel heat sink

International Nuclear Information System (INIS)

Om, N I; Gunnasegaran, P; Rajasegaran, S

2013-01-01

In this paper, the effect of sinusoidal flow on the thermal and hydraulic performance of microchannel heat sink (MCHS) is numerically investigated. This investigation covers Reynolds number in the range of 100 ≤ Re ≤ 1000 and pure water is used as a working fluid. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using finite volume method (FVM). The water flow field and heat transfer performance inside the sinusoidal microchannels is simulated and the results are compared with the straight microchannels. The effect of using sinusoidal microchannels on temperature distribution, Nusselt number, friction factor and thermal resistance is presented in this paper. It is found that with same rectangular cross-section, sinusoidal microchannels have a better heat transfer performance compared to the straight microchannels.

Characterization of microchannel anechoic corners formed by surface acoustic waves

Science.gov (United States)

Destgeer, Ghulam; Alam, Ashar; Ahmed, Husnain; Park, Jinsoo; Jung, Jin Ho; Park, Kwangseok; Sung, Hyung Jin

2018-02-01

Surface acoustic waves (SAWs) generated in a piezoelectric substrate couple with a liquid according to Snell's law such that a compressional acoustic wave propagates obliquely at a Rayleigh angle ( θ t) inside the microchannel to form a region devoid of a direct acoustic field, which is termed a microchannel anechoic corner (MAC). In the present study, we used microchannels with various heights and widths to characterize the width of the MAC region formed by a single travelling SAW. The attenuation of high-frequency SAWs produced a strong acoustic streaming flow that moved the particles in and out of the MAC region, whereas reflections of the acoustic waves within the microchannel resulted in standing acoustic waves that trapped particles at acoustic pressure nodes located within or outside of the MAC region. A range of actuation frequencies and particle diameters were used to investigate the effects of the acoustic streaming flow and the direct acoustic radiation forces by the travelling as well as standing waves on the particle motion with respect to the MAC region. The width of the MAC ( w c), measured experimentally by tracing the particles, increased with the height of the microchannel ( h m) according to a simple trigonometric equation w c = h m × tan ( θ t ).

Mama na Mtoto: Barriers and enablers to gender, equity and scale ...

International Development Research Centre (IDRC) Digital Library (Canada)

In Tanzania, a project popularly known as “MamaToto” (mother-baby) is building local capacity to improve maternal, newborn, and child health (MNCH). It is testing a comprehensive MNCH package that builds on district-led implementation, evidence, and best practices from similar efforts in Uganda. It aims to reduce ...

Detection of Aeromonas hydrophila Using Fiber Optic Microchannel Sensor

Directory of Open Access Journals (Sweden)

Samla Gauri

2017-01-01

Full Text Available This research focuses on the detection of Aeromonas hydrophila using fiber optic microchannel biosensor. Microchannel was fabricated by photolithography method. The fiber optic was chosen as signal transmitting medium and light absorption characteristic of different microorganisms was investigated for possible detection. Experimental results showed that Aeromonas hydrophila can be detected at the region of UV-Vis spectra between 352 nm and 354 nm which was comparable to measurement provided by UV spectrophotometer and also theoretical calculation by Beer-Lambert Absorption Law. The entire detection can be done in less than 10 minutes using a total volume of 3 μL only. This result promises good potential of this fiber optic microchannel sensor as a reliable, portable, and disposable sensor.

Metástasis hipofisaria de carcinoma de mama debutando como diabetes insípida

Directory of Open Access Journals (Sweden)

Ana Arévalo

2012-03-01

Full Text Available Los tumores metastáticos que afectan a la glándula hipofisaria son hallazgos pocos comunes, presentándose en cerca del 1% de las cirugías hipofisarias. Los autores presentan el caso de una paciente mujer de 46 años que debuta con síntomas de diabetes insípida. Había sido tratada 3 años antes por un carcinoma ductal infiltrante de la mama derecha. Las imágenes de resonancia magnética cerebral mostraron una masa en la silla turca con extensión supraselar. La paciente fue sometida a resección tumoral vía transesfenoidal que demostró metástasis de carcinoma de mama.

Two-phase flow instabilities in a silicon microchannels heat sink

International Nuclear Information System (INIS)

Bogojevic, D.; Sefiane, K.; Walton, A.J.; Lin, H.; Cummins, G.

2009-01-01

Two-phase flow instabilities are highly undesirable in microchannels-based heat sinks as they can lead to temperature oscillations with high amplitudes, premature critical heat flux and mechanical vibrations. This work is an experimental study of boiling instabilities in a microchannel silicon heat sink with 40 parallel rectangular microchannels, having a length of 15 mm and a hydraulic diameter of 194 μm. A series of experiments have been carried out to investigate pressure and temperature oscillations during the flow boiling instabilities under uniform heating, using water as a cooling liquid. Thin nickel film thermometers, integrated on the back side of a heat sink with microchannels, were used in order to obtain a better insight related to temperature fluctuations caused by two-phase flow instabilities. Flow regime maps are presented for two inlet water temperatures, showing stable and unstable flow regimes. It was observed that boiling leads to asymmetrical flow distribution within microchannels that result in high temperature non-uniformity and the simultaneously existence of different flow regimes along the transverse direction. Two types of two-phase flow instabilities with appreciable pressure and temperature fluctuations were observed, that depended on the heat to mass flux ratio and inlet water temperature. These were high amplitude/low frequency and low amplitude/high frequency instabilities. High speed camera imaging, performed simultaneously with pressure and temperature measurements, showed that inlet/outlet pressure and the temperature fluctuations existed due to alternation between liquid/two-phase/vapour flows. It was also determined that the inlet water subcooling condition affects the magnitudes of the temperature oscillations in two-phase flow instabilities and flow distribution within the microchannels.

Stabilization of two-phase octanol/water flows inside poly(dimethylsiloxane) microchannels using polymer coatings

NARCIS (Netherlands)

van der Linden, H. J.; Jellema, L. C.; Holwerda, M.; Verpoorte, E.

In this paper we present our first results on the realization of stable water/octanol, two-phase flows inside poly(dimethylsiloxane) (PDMS) microchannels. Native PDMS microchannels were coated with high molecular weight polymers to change the surface properties of the microchannels and thus

A new ion detector array and digital-signal-processor-based interface

International Nuclear Information System (INIS)

Langstaff, D.P.; McGinnity, T.M.; Forbes, D.M.; Birkinshaw, K.; Lawton, M.W.

1994-01-01

A new one-dimensional ion detector array on a silicon chip has been developed for use in mass spectrometry. It is much smaller and simpler than electro-optical arrays currently in use and in addition has a higher resolution and a zero noise level. The array consists of a one-dimensional array of metal strips (electrodes) with a pitch of 25 μm on the top surface of a silicon chip, each electrode having its own charge pulse sensor, 8-bit counter and control/interface circuitry. The chip is mounted on a ceramic substrate and is preceded by a micro-channel plate electron multiplier. Chips are butted to give a longer array. Test results show a stable operating region. A digital-signal-processor-based interface is described, which controls the mode of operation and reads the accumulated array data at the maximum rate to avoid counter overflow. (author)

A new ion detector array and digital-signal-processor-based interface

Energy Technology Data Exchange (ETDEWEB)

Langstaff, D.P.; McGinnity, T.M.; Forbes, D.M.; Birkinshaw, K. (University Coll. of Wales, Aberystwyth (United Kingdom). Dept. of Physics); Lawton, M.W. (University of Wales Aberystwyth (United Kingdom). Dept. of Computer Science)

1994-04-01

A new one-dimensional ion detector array on a silicon chip has been developed for use in mass spectrometry. It is much smaller and simpler than electro-optical arrays currently in use and in addition has a higher resolution and a zero noise level. The array consists of a one-dimensional array of metal strips (electrodes) with a pitch of 25 [mu]m on the top surface of a silicon chip, each electrode having its own charge pulse sensor, 8-bit counter and control/interface circuitry. The chip is mounted on a ceramic substrate and is preceded by a micro-channel plate electron multiplier. Chips are butted to give a longer array. Test results show a stable operating region. A digital-signal-processor-based interface is described, which controls the mode of operation and reads the accumulated array data at the maximum rate to avoid counter overflow. (author).

Aleitamento materno como fator de proteção para o câncer de mama

Directory of Open Access Journals (Sweden)

Clícia Valim Côrtes Gradim

2011-01-01

Full Text Available Estudio cuantitativo, transversal que tuvo como objetivo verificar si las mujeres que amamantaron relacionan este acto como un factor de protección para el cáncer de mama. Se aplicó un formulario a 200 mujeres que amamantaron, y solían frecuentar una clínica municipal en Alfenas-Míi, entre mayo y julio de 2008. El análisis de los datos se basó en la estadística descriptiva yen el test chí cuadrado, con nivel de sígntñcancta de 5%. El índice de asociación entre la lactancia materna y el cáncer de mama fue de 3S%. La escolaridad estuvo significativamente relacionada al conocimiento de la lactancia materna no exclusiva como un factor de protección para esa neoplasia mamaria (p <0,001. Los profesionales de la salud deben alentar y concíentízar a las mujeres acerca de las ventajas de la lactancia materna, tanto sobre los beneficios para el niño como para la madre, pues la protege del cáncer de mama.

Entrevista motivacional no suporte social de cuidadores de pacientes com câncer de mama em quimioterapia

Directory of Open Access Journals (Sweden)

Carla Monique Lopes Mourão

2017-12-01

Full Text Available RESUMO Objetivo: Avaliar os efeitos da entrevista motivacional para mudança de comportamento de suporte social junto a cuidadores de pacientes com câncer de mama em quimioterapia. Método: Estudo quase experimental, realizado com mulheres em quimioterapia para câncer de mama e com os cuidadores das respectivas mulheres entrevistadas. A intervenção foi a Entrevista Motivacional Breve, aplicada aos cuidadores indicados pelas pacientes em quatro sessões individuais, com intervalos semanais e duração de 30 minutos cada. O comportamento de suporte social foi avaliado pelas mulheres antes e depois da intervenção pela Escala de Suporte Social. Resultados: Participaram do estudo 18 mulheres e 18 cuidadores. O suporte social das mulheres se mostrou elevado tanto para a dimensão emocional quanto para a instrumental da Escala de Suporte Social, após intervenção utilizada com os cuidadores pela Entrevista Motivacional Breve. Os achados contribuem para a prática clínica de diversas categorias profissionais, na utilização de estratégias de intervenção de baixo custo para melhoria da qualidade de vida durante e após o tratamento de mulheres com câncer de mama. Conclusão: A intervenção utilizada promoveu de forma positiva a mudança comportamental, melhorando o suporte social prestado pelos cuidadores às pacientes com câncer de mama e em realização de quimioterapia.

Enhanced MicroChannel Heat Transfer in Macro-Geometry using Conventional Fabrication Approach

Science.gov (United States)

Ooi, KT; Goh, AL

2016-09-01

This paper presents studies on passive, single-phase, enhanced microchannel heat transfer in conventionally sized geometry. The intention is to allow economical, simple and readily available conventional fabrication techniques to be used for fabricating macro-scale heat exchangers with microchannel heat transfer capability. A concentric annular gap between a 20 mm diameter channel and an 19.4 mm diameter insert forms a microchannel where heat transfer occurs. Results show that the heat transfer coefficient of more than 50 kW/m·K can be obtained for Re≈4,000, at hydraulic diameter of 0.6 mm. The pressure drop values of the system are kept below 3.3 bars. The present study re-confirms the feasibility of fabricating macro-heat exchangers with microchannel heat transfer capability.

Desarrollo investigativo en salud sexual de mujeres con cáncer de mama: una revisión integrativa

Directory of Open Access Journals (Sweden)

Luz Stella Bueno Robles

2016-01-01

Full Text Available Objetivo: Caracterizar la producción científica relacionada con la salud sexual en mujeres con cáncer de mama. Metodología: Revisión integrativa. Se realizó una búsqueda en las bases de datos Scopus, Medline, LILACS y SciELO, así como búsquedas secundarias en revistas científicas. Se encontraron 85 artículos organizados y caracterizados por año, idioma y continente; edad promedio y tipos de tratamiento; metodología, perspectiva, enfoque, diseño, perspectiva disciplinar y tendencia temática. Resultados: La temática reportó mayor producción de conocimiento en los últimos 10 años. La tendencia de investigación se orienta hacia tres categorías: Salud sexual y cáncer de mama; Salud sexual en la mujer y tratamientos del cáncer de mama; y Salud sexual y relaciones de pareja. Conclusiones: La salud sexual en mujeres con cáncer de mama es un aspecto importante en la calidad de vida, que continuamente se ve alterada como resultado de la enfermedad y los efectos adversos de los tratamientos. Esta condición no sólo aqueja a la persona enferma, sino también a su pareja, por lo que se requiere del desarrollo de líneas de acción que permitan dar una atención integral a las mujeres con esta enfermedad.

Morbilidad del cáncer de mama en la mujer

Directory of Open Access Journals (Sweden)

Raúl Morales González

1999-01-01

Full Text Available Realizamos un estudio retroprospectivo con 50 pacientes pertenecientes al área de salud del Policlínico Comunitario No. 1 de Manzanillo, con diagnóstico citomorfológico de cáncer de mama, atendidas en la Consulta Central de Mama del Hospital "Celia Sánchez Manduley", desde enero de 1990 hasta diciembre de 1997. Se analizan algunos factores relacionados con la morbilidad del cáncer de mama en la mujer de nuestro medio. La información se procesó por medidas estadísticas como números absolutos, porcentajes y tasa de prevalencia. La enfermedad fue más frecuente en la 5ta. y 7ma. décadas de la vida; el mayor riesgo de enfermar se presentó de los 70 años, y la tasa de prevalencia del área es de 21,9 por 10 000 mujeres. Las mujeres con embarazos múltiples se asociaron con una disminución en la incidencia del cáncer mamario, el cáncer afectó más a las obesas y a las que tenían el hábito de ingerir bebidas alcohólicas.A retrospective study of 50 patients from the health area of the Community Polyclinic No. 1, in Manzanillo, was conducted. These women had a cytomorphological diagnosis of breast cancer and were attended at the Central Breast Department of the "Celia Sánchez Manduley" Hospital, from January, 1990, to December, 1997. Some factors related to morbidity from breast cancer in our environment were analyzed. The information was processed by statistical measures with absolute numbers, percentages and prevalence rate. The disease was more frequent in the 5th and 7th decades of life. Those aged 70 were at the highest risk for getting sick. The prevalence rate of the area was 21.9 per 10 000 women. Multiparous women were associated with a reduction in the incidence of breast cancer. Obese women and those with drinking habit were more affected by cancer.

Plaguicidas y cáncer de mama en mujeres cordobesas

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R. Angulo Lucena

2001-06-01

Full Text Available La exposición a contaminantes ambientales constituye en la actualidad un problema importante en salud pública, sobre todo con respecto al papel que dichos tóxicos juegan como carcinogenéticos. Este hecho junto con la incidencia creciente del cáncer de mama en España y de que no existe una relación clara entre esta patología y la exposición a plaguicidas, conduce a plantearnos evaluar el papel de los plaguicidas como factor de riesgo en el cáncer de mama en mujeres cordobesas.Se realiza un estudio de casos-controles en 134 mujeres que fueron sometidas a intervenciones quirúrgicas por lesiones mamarias en el Hospital Universitario Reina Sofía de Córdoba. A todas se les realiza un cuestionario, así como un estudio anatomopatológico y determinaciones en grasa mamaria de cuatro plaguicidas (HCB, HCH, p,p’DDE y Aldrín mediante cromatografía de gases.Tras el estudio anatomopatológico se estableció que 69 presentaban lesiones malignas (casos y 65 lesiones benignas (controles. Las determinaciones analíticas respecto a los 4 plaguicidas, detectan niveles elevados de p,p’DDE en todas las muestras, seguidas del HCB y Aldrín y en menores niveles y muestras se detecta el HCH.El análisis univariante detectó la edad, duración de la lactancia y niveles de Aldrín como factores de riesgo en las lesiones malignas, pero el análisis multivariante identificó los niveles del pesticida Aldrín como el factor más significativo en dichas lesiones (p < 0.001.Se establece la relación causal entre Aldrín y cáncer de mama, y se sugiere la necesidad de realizar nuevos estudios para eliminar los factores de confusión.

A bio-inspired, microchanneled hydrogel with controlled spacing of cell adhesion ligands regulates 3D spatial organization of cells and tissue.

Science.gov (United States)

Lee, Min Kyung; Rich, Max H; Lee, Jonghwi; Kong, Hyunjoon

2015-07-01

Bioactive hydrogels have been extensively studied as a platform for 3D cell culture and tissue regeneration. One of the key desired design parameters is the ability to control spatial organization of biomolecules and cells and subsequent tissue in a 3D matrix. To this end, this study presents a simple but advanced method to spatially organize microchanneled, cell adherent gel blocks and non-adherent ones in a single construct. This hydrogel system was prepared by first fabricating a bimodal hydrogel in which the microscale, alginate gel blocks modified with cell adhesion peptides containing Arg-Gly-Asp sequence (RGD peptides), and those free of RGD peptides, were alternatingly presented. Then, anisotropically aligned microchannels were introduced by uniaxial freeze-drying of the bimodal hydrogel. The resulting gel system could drive bone marrow stromal cells to adhere to and differentiate into neuron and glial cells exclusively in microchannels of the alginate gel blocks modified with RGD peptides. Separately, the bimodal gel loaded with microparticles releasing vascular endothelial growth factor stimulated vascular growth solely into microchannels of the RGD-alginate gel blocks in vivo. These results were not attained by the bimodal hydrogel fabricated to present randomly oriented micropores. Overall, the bimodal gel system could regulate spatial organization of nerve-like tissue or blood vessels at sub-micrometer length scale. We believe that the hydrogel assembly demonstrated in this study will be highly useful in developing a better understanding of diverse cellular behaviors in 3D tissue and further improve quality of a wide array of engineered tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cirugía conservadora y radical en estadíos tempranos del cáncer de mama

OpenAIRE

Nápoles Izquierdo, Yunexis; García Novoa, Wilfredo; Díaz Agüero, Heriberto; Báez Pupo, María Margarita

2009-01-01

Fundamento: El cáncer de mama es un problema de salud a escala internacional la cual ha aumentado en los últimos años las tasas de morbilidad y mortalidad, se plantea que cada quince minutos fallece una mujer por esta causa. Objetivo: Valorar los resultados de la cirugía conservadora y radical en estadíos tempranos del cáncer de mama. Método: Se realizó un estudio retrospectivo de casos y controles, la muestra estuvo constituida por treinta pacientes, a las que se le aplicó cirugía conservado...

Developing a method of fabricating microchannels using plant root structure

Science.gov (United States)

Nakashima, Shota; Tokumaru, Kazuki; Tsumori, Fujio

2018-06-01

Complicated three-dimensional (3D) microchannels are expected to be applied to a lab-on-a-chip, especially an organ-on-a-chip. There are fine microchannel networks such as blood vessels in a living organ. However, it is difficult to recreate the complicated 3D microchannels of real living structures. Plant roots have a similar structure to blood vessels. They spread radially and three-dimensionally, and become thinner as they branch. In this research, we propose a method of fabricating microchannels using a live plant root as a template to mimic a blood vessel structure. We grew a plant in ceramic slurry instead of soil. The slurry consists of ceramic powder, binder and water, so it plays a similar role to soil consisting of fine particles in water. After growing the plant, the roots inside the slurry were burned and a sintered ceramic body with channel structures was obtained by heating. We used two types of slurry with different composition ratios, and compared the internal channel structures before and after sintering.

Thermal mixing of two miscible fluids in a T-shaped microchannel.

Science.gov (United States)

Xu, Bin; Wong, Teck Neng; Nguyen, Nam-Trung; Che, Zhizhao; Chai, John Chee Kiong

2010-10-01

In this paper, thermal mixing characteristics of two miscible fluids in a T-shaped microchannel are investigated theoretically, experimentally, and numerically. Thermal mixing processes in a T-shaped microchannel are divided into two zones, consisting of a T-junction and a mixing channel. An analytical two-dimensional model was first built to describe the heat transfer processes in the mixing channel. In the experiments, de-ionized water was employed as the working fluid. Laser induced fluorescence method was used to measure the fluid temperature field in the microchannel. Different combinations of flow rate ratios were studied to investigate the thermal mixing characteristics in the microchannel. At the T-junction, thermal diffusion is found to be dominant in this area due to the striation in the temperature contours. In the mixing channel, heat transfer processes are found to be controlled by thermal diffusion and convection. Measured temperature profiles at the T-junction and mixing channel are compared with analytical model and numerical simulation, respectively.

Unificación de subunidades estéticas de la mama en reconstrucción autóloga postmastectomia

Directory of Open Access Journals (Sweden)

M. Mendieta-Espinosa

2015-12-01

Full Text Available La restauración de la mama es un componente esencial en el tratamiento curativo del cáncer tras la mastectomía, ya que una cicatriz o una reconstrucción con malos resultados estéticos se traducen para la mujer en un recordatorio constante de la enfermedad. Para la reconstrucción de mama planteamos un modelo según subunidades estéticas, ya que en ella se encuentran distintos componentes y diferentes distribuciones de volúmenes que caracterizan a cada mama en particular según el hábito corporal de la paciente. Nuestro objetivo es no ver la mama como un montículo único, sino compuesto por distintas subunidades que pueden ser restauradas con un adecuado posicionamiento de los colgajos autólogos. Realizamos un total de 32 reconstrucciones mamarias con colgajos basados en el abdomen para la restauración e integración de sus subunidades estéticas, ya que los colgajos abdominales brindan la ventaja de poder ser moldeados según las necesidades, particularidad que no ofrecen los materiales aloplásticos, y así poder lograr una transición suave de la mama a la pared torácica. La reconstrucción del complejo areola pezón y los procedimientos de simetrización de la mama sana como reducción o mastopexia, los efectuamos 6 meses después del procedimiento inicial, utilizando las mismas subunidades para valorar el resultado así como para mejorar las zonas de continuidad mediante la aplicación de lipoinyección grasa o revisión de cicatrices. De las 32 reconstrucciones autólogas realizadas, 28 obtuvieron un adecuado contorno del colgajo, continuidad con la pared torácica, y un adecuado posicionamiento del surco submamario, con buena simetría de la mama contralateral. En 4 reconstrucciones no logramos la adecuada unificación de las subunidades: en 2 hubo una apariencia del colgajo en parche, y en 2 quedó un posicionamiento muy bajo del nuevo surco submamario. El enfoque del principio de subunidades propuesto para la reconstrucci

Supervivencia al cáncer de mama: Una historia personal (Breast Cancer Survivorship—A Personal Story)

Centers for Disease Control (CDC) Podcasts

2016-10-18

Pam Bryant, una sobreviviente de cáncer de mama, habla sobre su viaje personal y cómo impactó su vida el recibir un diagnóstico de cáncer de mama antes de los 45 años. .  Created: 10/18/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Division of Cancer Prevention and Control (DCPC).   Date Released: 10/18/2016.

Mulher portadora de câncer de mama: percepção sobre a doença, família e sociedade

Directory of Open Access Journals (Sweden)

Sinvalana Schwerez Funghetto

2003-10-01

Full Text Available Estudo da compreensão das diferentes situações vivenciadas pelas mulheres portadoras de câncer de mama que participavam no grupo de apoio do Ambulatório de Quimioterapia, da Sociedade Hospital de Caridade de Santa Rosa - RS, no período de agosto de 1999 a setembro de 2000.Teve como objetivo, a partir de alguns conceitos teóricos da Teoria de Consecução de Metas, de Imogene King, avaliar a percepção da mulher portadora de câncer de mama em relação a sua doença, família e sociedade. Para coleta de dados foram realizadas entrevistas semi­estruturadas. À mulher, com câncer de mama, sente limitações de ordem social, física e emocional em busca de conhecimentos e de informações sobre a doença e a vida. À enfermagem cabe repensar a prática do cuidar de uma mulher com câncer de mama, assistindo­a com respeito, ética, valorização da vida humana e sensibilidade.

Experimental and theoretical analysis of defocused CO2 laser microchanneling on PMMA for enhanced surface finish

Science.gov (United States)

Prakash, Shashi; Kumar, Subrata

2017-02-01

The poor surface finish of CO2 laser-micromachined microchannel walls is a major limitation of its utilization despite several key advantages, like low fabrication cost and low time consumption. Defocused CO2 laser beam machining is an effective solution for fabricating smooth microchannel walls on polymer and glass substrates. In this research work, the CO2 laser microchanneling process on PMMA has been analyzed at different beam defocus positions. Defocused processing has been investigated both theoretically and experimentally, and the depth of focus and beam diameter have been determined experimentally. The effect of beam defocusing on the microchannel width, depth, surface roughness, heat affected zone and microchannel profile were examined. A previously developed analytical model for microchannel depth prediction has been improved by incorporating the threshold energy density factor. A semi-analytical model for predicting the microchannel width at different defocus positions has been developed. A semi-empirical model has also been developed for predicting microchannel widths at different defocusing conditions for lower depth values. The developed models were compared and verified by performing actual experiments. Multi-objective optimization was performed to select the best optimum set of input parameters for achieving the desired surface roughness.

A two-step sealing-and-reinforcement SU8 bonding paradigm for the fabrication of shallow microchannels

Science.gov (United States)

Mehboudi, Aryan; Yeom, Junghoon

2018-03-01

Adhesive bonding is a key technique to create microfluidic devices when two separate substrates are used to form microchannels. Among many adhesives explored in microchannel fabrication, SU8 has been widely used as an adhesive layer for sealing the microchannel sidewalls. The majority of the available SU8-based bonding methods, however, suffer from the difficulties associated with sealing of two important types of the microchannel architecture: (1) shallow microchannels with small patterns on a large area, and (2) microchannels with ultra-low aspect ratios (e.g. 6 mm in width and 2~μ m in height). In this paper, a new bonding paradigm based upon the low-temperature and low-pressure SU8 bonding, consisting of two steps of sealing using a thin-SU8-coated PET film and bonding reinforcement using a SU8-coated glass slide, is proposed to resolve the aforementioned difficulties. Since it does not need complicated instruments such as a wafer bonding machine and a lamination device, the developed bonding paradigm is convenient and economical. We successfully demonstrate the compatibility of the proposed bonding paradigm with the two microchannel fabrication approaches based on the glass wet etching and the SU8 photo-lithography, where small microchannels with the innermost surfaces fully made of SU8 are obtained. A theoretical model is employed to better investigate the flow characteristics and the structural behavior of the microchannel including the PET film deformation, strain and von Mises stress distributions, bonding strength, etc. Moreover, we demonstrate the fabrication of the multi-height deep-shallow microchannel sidewalls and their sealing using the SU8-coated PET film. Finally, as a proof-of-concept device, a microfluidic filter consisting of the double-height deep-shallow microchannel is fabricated for separation of 3 µm and 10 µm particles.

Study of the electric field inside microchannel plate multipliers

International Nuclear Information System (INIS)

Gatti, E.; Oba, K.; Rehak, P.

1982-01-01

Electric field inside high gain microchannel plate multipliers was studied. The calculations were based directly on the solution of the Maxwell equations applied to the microchannel plate (MCP) rather than on the conventional lumped RC model. The results are important to explain the performance of MCP's, (1) under a pulsed bias tension and, (2) at high rate conditions. The results were tested experimentally and a new method of MCP operation free from the positive ion feedback was demonstrated

Compact Ceramic Microchannel Heat Exchangers

Energy Technology Data Exchange (ETDEWEB)

Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)

2016-10-31

The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

CÂNCER DE MAMA: ESTIMATIVA DA PREVALÊNCIA DE ANSIEDADE E DEPRESSÃO EM PACIENTES EM TRATAMENTO AMBULATORIAL

OpenAIRE

Ferreira, Andreia Silva; Bicalho, Bruna Pereira; Oda, Julie Massayo Maeda; Duarte, Sebastião Junior Henrique; Machado, Richardson Miranda

2016-01-01

A ansiedade e a depressão são doenças psicoemocionais que afetam grande parte das mulheres acometidas pelo câncer de mama. Pouco se sabe sobre os meios de identificação precoce, constituindo-se em desafios à equipe multiprofissional da saúde a integralidade do cuidado à vítima dessa doença. O objetivo deste estudo foi identificar a prevalência da ansiedade e depressão em mulheres em tratamento ambulatorial para o câncer de mama. Estudo descritivo transversal, realizado com 138 mulheres em tra...

Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

Energy Technology Data Exchange (ETDEWEB)

McCann, Ronán [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Bagga, Komal; Groarke, Robert [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); Stalcup, Apryll [Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Vázquez, Mercedes, E-mail: mercedes.vazquez@dcu.ie [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Brabazon, Dermot [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland)

2016-11-30

Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

International Nuclear Information System (INIS)

McCann, Ronán; Bagga, Komal; Groarke, Robert; Stalcup, Apryll; Vázquez, Mercedes; Brabazon, Dermot

2016-01-01

Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

Theoretical Study of Molecular Transport Through a Permeabilized Cell Membrane in a Microchannel.

Science.gov (United States)

Mahboubi, Masoumeh; Movahed, Saeid; Hosseini Abardeh, Reza; Hoshyargar, Vahid

2017-06-01

A two-dimensional model is developed to study the molecular transport into an immersed cell in a microchannel and to investigate the effects of finite boundary (a cell is suspended in a microchannel), amplitude of electric pulse, and geometrical parameter (microchannel height and size of electrodes) on cell uptake. Embedded electrodes on the walls of the microchannel generate the required electric pulse to permeabilize the cell membrane, pass the ions through the membrane, and transport them into the cell. The shape of electric pulses is square with the time span of 6 ms; their intensities are in the range of 2.2, 2.4, 2.6, 3 V. Numerical simulations have been performed to comprehensively investigate the molecular uptake into the cell. The obtained results of the current study demonstrate that calcium ions enter the cell from the anodic side (the side near positive electrode); after a while, the cell faces depletion of the calcium ions on a positive electrode-facing side within the microchannel; the duration of depletion depends on the amplitude of electric pulse and geometry that lasts from microseconds to milliseconds. By keeping geometrical parameters and time span constant, increment of a pulse intensity enhances molecular uptake and rate of propagation inside the cell. If a ratio of electrode size to cell diameter is larger than 1, the transported amount of Ca 2+ into the cell, as well as the rate of propagation, will be significantly increased. By increasing the height of the microchannel, the rate of uptake is decreased. In an infinite domain, the peak concentration becomes constant after reaching the maximum value; this value depends on the intra-extracellular conductivity and diffusion coefficient of interior and exterior domains of the cell. In comparison, the maximum concentration is changed by geometrical parameters in the microchannel. After reaching the maximum value, the peak concentration reduces due to the depletion of Ca 2+ ions within the

Farmacocinética, metabolismo e excreção renal da doxorrubicina em pacientes com câncer de mama

OpenAIRE

Leandro Francisco Pippa

2016-01-01

O presente estudo visa descrever a farmacocinética, o metabolismo e a excreção renal da doxorrubicina, uma antraciclina utilizada no tratamento do câncer de mama. A doxorrubicina é biotransformada a doxorrubicinol pelas enzimas carbonil redutase 1 e 3 e aldo-ceto redutase. Foram investigadas 12 pacientes portadoras de câncer de mama no primeiro ciclo de tratamento adjuvante ou neoadjuvante com doxorrubicina (60 mg/m2) administrada por infusão intravenosa durante 30 min. As amostras seriadas d...

Vital Signs – Derrotemos al cáncer de mama (Defeating Breast Cancer)

Centers for Disease Control (CDC) Podcasts

2012-11-12

Este podcast está basado en el informe Vital Signs de los CDC de noviembre del 2012. El cáncer de mama es la segunda causa principal de muerte por cáncer en las mujeres en los Estados Unidos. Mejores pruebas de detección y tratamientos han contribuido a una disminución en las muertes por cáncer de mama; sin embargo, no todas las mujeres se han beneficiado igualmente de estos avances. Sepa cómo todos podemos ayudar a reducir las muertes por esta enfermedad.  Created: 11/12/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 11/12/2012.

Caracterização da dor em mulheres após tratamento do câncer de mama

Directory of Open Access Journals (Sweden)

Vânia Tie Koga Ferreira

2014-03-01

Full Text Available Este estudo pretendeu caracterizar e localizar a dor nas mulheres submetidas ao tratamento por câncer de mama. Estudo de caráter exploratório, descritivo, com abordagem quantitativa, pelas medidas de tendência central e percentual. Pesquisa desenvolvida no Núcleo de Ensino e Pesquisa e Assistência na Reabilitação de Mastectomizadas com 30 mulheres. Os dados foram coletados no período de fevereiro a agosto de 2008, por meio de instrumento contendo variáveis capazes de caracterizar e localizar a dor, e foram tratados por meio de média, mediana, moda e desvio-padrão e percentual. Destacou-se que 56,7% mulheres referiram que a dor é diária, 46,7% mulheres referiram que a dor teve início após a cirurgia da mama, e para 40% a dor é constante. Conhecimento, reconhecimento e manejo do sintoma permitem ofertas terapêuticas alternativas para o alívio da dor, minimizando efeitos físicos e emocionais que podem ser causados na vida de mulheres submetidas ao tratamento por câncer de mama.

Investigation of Size Effects to the Mixing Performance on the X-shaped Micro-Channels

Directory of Open Access Journals (Sweden)

S Tu

2016-09-01

Full Text Available Due to the developing of micro-electro-mechanical-system, MEMS, the fabrication of the microminiaturization devices becomes obviously important. The advances in the basic understanding of fluid physics have opened an era of application of fluid dynamics systems using microchannels. The purpose of this study is to research the flow transport phenomenon by employing different kinds of micro-channel sizing in X-shaped micro-channels. As the working fluid, water is injected to microchannel at different mass flow rate. Over a wide range of flow condition, 1.06 < Re < 514, in X-shaped micro-channels, the mixture performances of numerical simulation, flow visualization, and temperature distribution remain the same. At the same mass flow rate as the Reynolds number below 112.53, the biggest channel size had the slowest flow velocity and got the best mixing performance; as the Reynolds number above 112.53, the smaller the channel sizing, the lower the pressure drops and the faster velocity becomes. The transition form early from laminar flow, the unsteady flow is an advantage for mixing in the limited mixing area, therefore 0.7 mm got the best mixing performance. It is clear that the size of the channel plays an important role in the X-shaped micro-channels.

Modular and efficient ozone systems based on massively parallel chemical processing in microchannel plasma arrays: performance and commercialization

Science.gov (United States)

Kim, M.-H.; Cho, J. H.; Park, S.-J.; Eden, J. G.

2017-08-01

Plasmachemical systems based on the production of a specific molecule (O3) in literally thousands of microchannel plasmas simultaneously have been demonstrated, developed and engineered over the past seven years, and commercialized. At the heart of this new plasma technology is the plasma chip, a flat aluminum strip fabricated by photolithographic and wet chemical processes and comprising 24-48 channels, micromachined into nanoporous aluminum oxide, with embedded electrodes. By integrating 4-6 chips into a module, the mass output of an ozone microplasma system is scaled linearly with the number of modules operating in parallel. A 115 g/hr (2.7 kg/day) ozone system, for example, is realized by the combined output of 18 modules comprising 72 chips and 1,800 microchannels. The implications of this plasma processing architecture for scaling ozone production capability, and reducing capital and service costs when introducing redundancy into the system, are profound. In contrast to conventional ozone generator technology, microplasma systems operate reliably (albeit with reduced output) in ambient air and humidity levels up to 90%, a characteristic attributable to the water adsorption/desorption properties and electrical breakdown strength of nanoporous alumina. Extensive testing has documented chip and system lifetimes (MTBF) beyond 5,000 hours, and efficiencies >130 g/kWh when oxygen is the feedstock gas. Furthermore, the weight and volume of microplasma systems are a factor of 3-10 lower than those for conventional ozone systems of comparable output. Massively-parallel plasmachemical processing offers functionality, performance, and commercial value beyond that afforded by conventional technology, and is currently in operation in more than 30 countries worldwide.

POSIBLES MECANISMOS DE ACCIÓN BIOLÓGICA DE LA ACTIVIDAD FÍSICA EN EL CÁNCER DE MAMA

OpenAIRE

Jairo Alejandro Fernández Ortega; José Antonio de Paz Fernández

2014-01-01

La evidencia científica ha demostrado la importancia de la actividad física como una estrategia efectiva para disminuir el riesgo y la recidiva del cáncer de mama. Sin embargo, hasta el momento no se conocen con precisión los mecanismos de acción biológicos del ejercicio sobre el cáncer de mama. El propósito de este artículo es realizar una revisión sistemática exhaustiva de la literatura e identificar las posibles hipótesis que se plantean de los mecanismos de acción biológicos del ejercicio...

Micro-channel convective boiling heat transfer with flow instabilities

International Nuclear Information System (INIS)

Consolini, L.; Thome, J.R.

2009-01-01

Flow boiling heat transfer in micro-channels has attracted much interest in the past decade, and is currently a strong candidate for high performance compact heat sinks, such as those required in electronics systems, automobile air conditioning units, micro-reactors, fuel cells, etc. Currently the literature presents numerous experimental studies on two-phase heat transfer in micro-channels, providing an extensive database that covers many different fluids and operating conditions. Among the noteworthy elements that have been reported in previous studies, is the sensitivity of micro-channel evaporators to oscillatory two-phase instabilities. These periodic fluctuations in flow and pressure drop either result from the presence of upstream compressibility, or are simply due to the interaction among parallel channels in multi-port systems. An oscillating flow presents singular characteristics that are expected to produce an effect on the local heat transfer mechanisms, and thus on the estimation of the two-phase heat transfer coefficients. The present investigation illustrates results for flow boiling of refrigerants R-134a, R-236fa, and R-245fa in a 510 μm circular micro-channel, exposed to various degrees of oscillatory compressible volume instabilities. The data describe the main features of the fluctuations in the temperatures of the heated wall and fluid, and draw attention to the differences in the measured unstable time-averaged heat transfer coefficients with respect to those for stable flow boiling. (author)

Micro-channel convective boiling heat transfer with flow instabilities

Energy Technology Data Exchange (ETDEWEB)

Consolini, L.; Thome, J.R. [Ecole Polytechnique Federale de Lausanne (Switzerland). Lab. de Transfert de Chaleur et de Masse], e-mail: lorenzo.consolini@epfl.ch, e-mail: john.thome@epfl.ch

2009-07-01

Flow boiling heat transfer in micro-channels has attracted much interest in the past decade, and is currently a strong candidate for high performance compact heat sinks, such as those required in electronics systems, automobile air conditioning units, micro-reactors, fuel cells, etc. Currently the literature presents numerous experimental studies on two-phase heat transfer in micro-channels, providing an extensive database that covers many different fluids and operating conditions. Among the noteworthy elements that have been reported in previous studies, is the sensitivity of micro-channel evaporators to oscillatory two-phase instabilities. These periodic fluctuations in flow and pressure drop either result from the presence of upstream compressibility, or are simply due to the interaction among parallel channels in multi-port systems. An oscillating flow presents singular characteristics that are expected to produce an effect on the local heat transfer mechanisms, and thus on the estimation of the two-phase heat transfer coefficients. The present investigation illustrates results for flow boiling of refrigerants R-134a, R-236fa, and R-245fa in a 510 {mu}m circular micro-channel, exposed to various degrees of oscillatory compressible volume instabilities. The data describe the main features of the fluctuations in the temperatures of the heated wall and fluid, and draw attention to the differences in the measured unstable time-averaged heat transfer coefficients with respect to those for stable flow boiling. (author)

Cuidando a las mujeres con cáncer de mama: el afrontamiento como predictor de la calidad de vida

OpenAIRE

Bueno Ferrán, Mercedes

2016-01-01

El cáncer de mama es un problema de salud relevante como indican sus cifras de incidencia, prevalencia, mortalidad y coste. La consideración del cáncer como enfermedad crónica, donde el paciente experimenta cambios que afectan tanto a nivel físico como psíquico y social, requiere un enfoque integral de la atención sanitaria. El impacto del cáncer en general y del cáncer de mama en particular, se extiende a todas las esferas de la vida de las personas afectadas y sus familias, impacto que detr...

Oficina de autoexame de mamas: uma estratégia para o autoconhecimento de adolescentes Taller de autoexamen de mamas: una estrategia para el autoconocimiento de adolescentes Workshop on breast self-examination: a strategy for self-knowledge of adolescents

Directory of Open Access Journals (Sweden)

Maria da Conceição Grego

2011-01-01

Full Text Available OBJETIVOS: Verificar a repercussão do conhecimento transmitido por meio da Oficina de autoexame de mamas e identificar a multiplicação de informações pelas participantes adolescentes. MÉTODOS: Trata-se de um estudo quantitativo, tipo Survey, realizado com 474 adolescentes de três escolas de Ensino Médio e Fundamental do município de Embu das Artes, em 2006 e 2007. RESULTADOS: Os dados das questões estruturadas e semiestruturadas, respondidas pelas participantes, mostraram as frequências das respostas acima de 50% da estimativa sobre a "repercussão do conteúdo da oficina" e abaixo dos 50% sobre a "ação multiplicadora". CONCLUSÃO: A Oficina auxilia a elaboração do conceito de si pelas adolescentes, de seu corpo, informa sobre o câncer de mama e os benefícios da adoção de práticas e atitudes saudáveis em seu cotidiano, empregando a técnica do autoexame de mamas como instrumento pedagógico.OBJETIVOS: Verificar la repercusión del conocimiento transmitido por medio del Taller de autoexamen de mamas e identificar la multiplicación de las informaciones por las participantes adolescentes. MÉTODOS: Se trata de un estudio cuantitativo, tipo Survey, realizado con 474 adolescentes de tres escuelas de Enseñanza Media y Fundamental del municipio de Embu de las Artes, en el 2006 y 2007. RESULTADOS: Los datos de las preguntas estructuradas y semiestructuradas, respondidas por las participantes, mostraron las frecuencias de las respuestas encima del 50% de la estimativa sobre la "repercusión del contenido del Taller" y abajo del 50% sobre la "acción multiplicadora". CONCLUSIÓN: El taller auxilia en la elaboración del concepto de sí por parte de las adolescentes, de su cuerpo, informa sobre el cáncer de mama y los beneficios de la adopción de prácticas y actitudes saludables en su cotidiano, empleando la técnica del autoexamen de mamas como instrumento pedagógico.OBJECTIVES: To verify the repercussions of knowledge

3D printed microchannel networks to direct vascularisation during endochondral bone repair.

Science.gov (United States)

Daly, Andrew C; Pitacco, Pierluca; Nulty, Jessica; Cunniffe, Gráinne M; Kelly, Daniel J

2018-04-01

Bone tissue engineering strategies that recapitulate the developmental process of endochondral ossification offer a promising route to bone repair. Clinical translation of such endochondral tissue engineering strategies will require overcoming a number of challenges, including the engineering of large and often anatomically complex cartilage grafts, as well as the persistence of core regions of avascular cartilage following their implantation into large bone defects. Here 3D printing technology is utilized to develop a versatile and scalable approach to guide vascularisation during endochondral bone repair. First, a sacrificial pluronic ink was used to 3D print interconnected microchannel networks in a mesenchymal stem cell (MSC) laden gelatin-methacryloyl (GelMA) hydrogel. These constructs (with and without microchannels) were next chondrogenically primed in vitro and then implanted into critically sized femoral bone defects in rats. The solid and microchanneled cartilage templates enhanced bone repair compared to untreated controls, with the solid cartilage templates (without microchannels) supporting the highest levels of total bone formation. However, the inclusion of 3D printed microchannels was found to promote osteoclast/immune cell invasion, hydrogel degradation, and vascularisation following implantation. In addition, the endochondral bone tissue engineering strategy was found to support comparable levels of bone healing to BMP-2 delivery, whilst promoting lower levels of heterotopic bone formation, with the microchanneled templates supporting the lowest levels of heterotopic bone formation. Taken together, these results demonstrate that 3D printed hypertrophic cartilage grafts represent a promising approach for the repair of complex bone fractures, particularly for larger defects where vascularisation will be a key challenge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Monte Carlo simulations of microchannel plate detectors I: steady-state voltage bias results

Energy Technology Data Exchange (ETDEWEB)

Ming Wu, Craig Kruschwitz, Dane Morgan, Jiaming Morgan

2008-07-01

X-ray detectors based on straight-channel microchannel plates (MCPs) are a powerful diagnostic tool for two-dimensional, time-resolved imaging and timeresolved x-ray spectroscopy in the fields of laser-driven inertial confinement fusion and fast z-pinch experiments. Understanding the behavior of microchannel plates as used in such detectors is critical to understanding the data obtained. The subject of this paper is a Monte Carlo computer code we have developed to simulate the electron cascade in a microchannel plate under a static applied voltage. Also included in the simulation is elastic reflection of low-energy electrons from the channel wall, which is important at lower voltages. When model results were compared to measured microchannel plate sensitivities, good agreement was found. Spatial resolution simulations of MCP-based detectors were also presented and found to agree with experimental measurements.

Experimental investigation of two-phase gas-liquid flow in microchannel with T-junction

Science.gov (United States)

Bartkus, German; Kozulin, Igor; Kuznetsov, Vladimir

2017-10-01

Using high-speed video recording and the method of dual laser scanning the gas-liquid flow was investigated in rectangular microchannels with an aspect ratio of 2.35 and 1.26. Experiments were earned out for the vertical flow of ethanol-nitrogen mixture in a microchannel with a cross section of 553×235 µm and for the horizontal flow of water-nitrogen mixture in a microchannel with a cross section of 315×250 µm. The T-mixer was used at the channel's inlet for gas-liquid flow formation. It was observed that elongated bubble, transition, and annular flows are the main regimes for a microchannel with a hydraulic diameter substantially less than the capillary constant. Using laser scanning, the maps of flow regimes for ethanol-nitrogen and water-nitrogen mixtures were obtained and discussed.

Efecto de las alteraciones genéticas, epigenéticas y expresión transcripcional de cadherina-E en la susceptibilidad al cáncer de mama

Directory of Open Access Journals (Sweden)

Andrés Felipe Aristizábal-Pachón

2016-12-01

Full Text Available Introducción. La cadherina-E (CDH1 cumple un papel importante en la transición epitelio-mesénquima y está relacionada con la invasión y metástasis en varios tipos de carcinomas. Sin embargo, el efecto de mutaciones y epimutaciones germinales en la susceptibilidad al cáncer de mama no es claro. Objetivo. Evaluar el polimorfismo rs5030625, cambios en el patrón de metilación del promotor y expresión transcripcional de CDH1 en pacientes con cáncer de mama. Materiales y métodos. Fueron colectadas muestras de sangre periférica de 102 pacientes con cáncer de mama y 102 mujeres control. La genotipificación del polimorfismo rs5030625 fue realizado a través de PCR-RFLP; la PCR y el análisis de disociación de alta resolución sensibles a metilación fueron usadas para determinar el estatus y semicuantificar el nivel de metilación del promotor de CDH1; finalmente, la RT-qPCR permitió evaluar el nivel de expresión transcripcional de CDH1. Resultados. Los resultados no mostraron asociación entre el polimorfismo rs5030625 y el cáncer de mama. Se encontraron perfiles aberrantes de metilación del promotor de CDH1, en las pacientes con cáncer de mama, relacionados con las primeras etapas de desarrollo del cáncer. La disminución de la expresión de CDH1 fue asociada con la presencia de metástasis y el estatus metilado del promotor. Conclusión. Alteraciones en CDH1 fueron relacionadas con invasión y metástasis en cáncer de mama, proporcionando evidencia adicional de la relevancia de CDH1 en el desarrollo y progresión del cáncer de mama.

Characterization of a patch-clamp microchannel array towards neuronal networks analysis

DEFF Research Database (Denmark)

Alberti, Massimo; Snakenborg, Detlef; Lopacinska, Joanna M.

2010-01-01

for simultaneous patch clamping of cultured cells or neurons in the same network. A disposable silicon/silicon dioxide (Si/SiO2) chip with a microhole array was integrated in a microfluidic system for cell handling, perfusion and electrical recording. Fluidic characterization showed that our PC mu CA can work...

A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

Science.gov (United States)

Kimble, Randy A.; Pain, Bedabrata; Norton, Timothy J.; Haas, J. Patrick; Oegerle, William R. (Technical Monitor)

2002-01-01

Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest of by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

Micro-PIV/LIF measurements on electrokinetically-driven flow in surface modified microchannels

International Nuclear Information System (INIS)

Ichiyanagi, Mitsuhisa; Sasaki, Seiichi; Sato, Yohei; Hishida, Koichi

2009-01-01

Effects of surface modification patterning on flow characteristics were investigated experimentally by measuring electroosmotic flow velocities, which were obtained by micron-resolution particle image velocimetry using a confocal microscope. The depth-wise velocity was evaluated by using the continuity equation and the velocity data. The microchannel was composed of a poly(dimethylsiloxane) chip and a borosilicate cover-glass plate. Surface modification patterns were fabricated by modifying octadecyltrichlorosilane (OTS) on the glass surface. OTS can decrease the electroosmotic flow velocity compared to the velocity in the glass microchannel. For the surface charge varying parallel to the electric field, the depth-wise velocity was generated at the boundary area between OTS and the glass surfaces. For the surface charge varying perpendicular to the electric field, the depth-wise velocity did not form because the surface charge did not vary in the stream-wise direction. The surface charge pattern with the oblique stripes yielded a three-dimensional flow in a microchannel. Furthermore, the oblique patterning was applied to a mixing flow field in a T-shaped microchannel, and mixing efficiencies were evaluated from heterogeneity degree of fluorescent dye intensity, which was obtained by laser-induced fluorescence. It was found that the angle of the oblique stripes is an important factor to promote the span-wise and depth-wise momentum transport and contributes to the mixing flow in a microchannel

3D simulation of Heat transfer in MEMS-based microchannel

International Nuclear Information System (INIS)

Choi, Chi Woong; Huh, Cheol; Kim, Dong Eok; Kim, Moo Hwan

2007-01-01

The microchannel heat sink is promising heat dissipation method for high heat flux source. Contrary to conventional circular channel, MEMS based microchannel had rectangular or trapezoidal cross-sectional shape. In our study, we conducted three dimensional conjugate heat transfer calculation for rectangular shape microchannel. First, we simulated that channel was completely drained with known heating power. As a result we obtained calibration line, which indicates heat loss was function of temperature. Second, we simulated single phase heat transfer with various mass flux, 100-400 kg/m 2 s. In conclusion, the single phase test verified that the present heat loss evaluation method is applicable to micro scale heat transfer devices. Heat fluxes from each side wall shows difference due to non-uniform heating. However those ratios were correlated with supplied total heat. Finally, we proposed effective area correction factor to evaluate appropriate heat flux

Microchannel Reactor System for Catalytic Hydrogenation

Energy Technology Data Exchange (ETDEWEB)

Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie

2010-12-22

We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 – 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstrated on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.

Validez y seguridad del estadiamiento clínico axilar en el carcinoma infiltrante de mama

Directory of Open Access Journals (Sweden)

Yamilka Rodríguez Alberteri

Full Text Available Introducción: el correcto estadiamiento clínico en el cáncer de mama contribuye al éxito de la terapéutica, debe basarse en pruebas válidas y seguras. Objetivo: determinar la validez y seguridad del estadiamiento clínico axilar del cáncer de mama. Métodos: se realizó un estudio retrospectivo de 74 y 63 pacientes con carcinoma infiltrante de la mama y cirugía como primera opción terapéutica atendida en el Instituto Nacional de Oncología y Radiobiología de La Habana y el Centro Oncológico Territorial de Holguín en el primer semestre de 2010 y 2012. Se determinaron la validez y seguridad del estadiamiento clínico axilar empleado en ambos centros de conjunto y en cada uno de manera aislada, a través del cálculo de la sensibilidad, especificidad y sus índices de error complementarios: proporción de falsos positivos y de falsos negativos, así como los valores predictivos positivo y negativo como índices de seguridad. La prueba de oro fue el diagnóstico histopatológico. Resultados: en los tres casos, la sensibilidad superior al 54 % demostró una probabilidad de los métodos empleados para encontrar positividad axilar cuando había invasión metastásica y la especificidad mayor del 71 % expresó la capacidad del estadiamiento clínico axilar para clasificar clínicamente como negativas a las axilas no afectadas. Una axila clínicamente positiva fue dos veces más probable en un paciente con invasión axilar que en uno sin metástasis a este nivel. En los tres casos los valores predictivos positivos superaron el 61 % y los negativos el 73 %. Conclusiones: el estadiamiento clínico axilar en ambos centros fue una prueba válida y segura en pacientes con carcinoma infiltrante de la mama y cirugía como primera opción terapéutica.

O surgimento do câncer de mama na visão de um grupo de mulheres mastectomizadas

Directory of Open Access Journals (Sweden)

Ana Fátima Fernandes Carvalho

2004-01-01

Full Text Available El objetivo de este estudio fue identificar el surgimiento del cáncer de mama según la visión de un grupo de mujeres mastectomizadas. El estudio cualitativo fue desarrollado con 16 mujeres mastectomizadas, integrantes de un grupo de auto-ayuda, a través de observaciones y entrevistas. Las mujeres atribuyeron su cáncer a: sentimientos reprimidos, herencia familiar, estrés, trauma físico, hábitos alimentarios y la falta de cuidado con su propio cuerpo. Concluimos que las mujeres se mostraron más claras sobre la causa del surgimiento de su enfermedad, cuando indican los principales factores determinantes del cáncer de mama

Nuevas aportaciones a la búsqueda de genes de predisposición al cáncer de mama hereditario

OpenAIRE

Fernández García, Daniel

2014-01-01

[ES] El cáncer de mama es el más frecuente en mujeres y la principal causa de muerte tanto en países desarrollados como en países en desarrollo, representando un 23 % del total de nuevos casos de cáncer (se estima en 1 millón de nuevos casos cada año) y un 14 % del total de muertes en 2008 (Jemal et al. 2011). Aproximadamente un 5-10% de los cánceres de mama tienen una predisposición genética debido a la presencia de mutaciones germinales de genes de susceptibilidad, de forma que el aumen...

Linfoma no Hodgkin primario de mama, revisión de la literatura y presentación de un caso

Directory of Open Access Journals (Sweden)

Caridad Verdecia Cañizares

2011-06-01

Full Text Available El linfoma no Hodgkin primario de la mama es una entidad poco frecuente en pediatría y representa el 0,4 al 0,5 % de todos los tumores mamarios malignos. Debido a que carecen de características propias, tanto clínicas, citológicas como ecográficas, resulta muy difícil establecer el diagnóstico preoperatorio. Se presenta el caso de un linfoma no Hodgkin primario de la mama en una paciente de 3 años que llegó en estadio avanzado de la enfermedad, y se subraya la importancia del tratamiento en un equipo multidisciplinario.

Microchannel plates as detectors and amplifiers of x-ray images

International Nuclear Information System (INIS)

Wiedwald, J.D.

1992-08-01

Two decades of development driven largely by military night vision applications has led to the availability of a wide selection of microchannel plates for use by the scientific community. Microchannel plates (MCPs) are electron multipliers which retain a high degree of spatial resolution making it possible to amplify electron images by factors of 1,000 or more. Plates having 40 mm diameter and intrinsic spatial resolution of 8 μm are readily available. By coating the front surface of a microchannel plate with an x-ray sensitive photocathode material, x-ray images can be detected and amplified. While the detective quantum efficiency is relatively low, the low noise of the MCP (including the ability to construct images by single photon detection) and its high dynamic range make it suitable for some x-ray microscopy applications. The principles of MCP operation and typical performance are discussed. Examples of related applications and commercial capabilities are also presented

Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

Energy Technology Data Exchange (ETDEWEB)

Masilamani, Kannan; Ganguly, Suvankar; Feichtinger, Christian; Bartuschat, Dominik; Rüde, Ulrich, E-mail: suva_112@yahoo.co.in [Department of Computer Science 10 University of Erlangen-Nuremberg, Cauerstr.11 91058 Erlangen (Germany)

2015-06-15

In this paper, a hybrid lattice-Boltzmann and finite-difference (LB-FD) model is applied to simulate the effects of three-dimensional surface roughness and electrokinetic heterogeneity on electroosmotic flow (EOF) in a microchannel. The lattice-Boltzmann (LB) method has been employed to obtain the flow field and a finite-difference (FD) method is used to solve the Poisson-Boltzmann (PB) equation for the electrostatic potential distribution. Numerical simulation of flow through a square cross-section microchannel with designed roughness is conducted and the results are critically analysed. The effects of surface heterogeneity on the electroosmotic transport are investigated for different roughness height, width, roughness interval spacing, and roughness surface potential. Numerical simulations reveal that the presence of surface roughness changes the nature of electroosmotic transport through the microchannel. It is found that the electroosmotic velocity decreases with the increase in roughness height and the velocity profile becomes asymmetric. For the same height of the roughness elements, the EOF velocity rises with the increase in roughness width. For the heterogeneously charged rough channel, the velocity profile shows a distinct deviation from the conventional plug-like flow pattern. The simulation results also indicate locally induced flow vortices which can be utilized to enhance the flow and mixing within the microchannel. The present study has important implications towards electrokinetic flow control in the microchannel, and can provide an efficient way to design a microfluidic system of practical interest. (paper)

Active Micro structured Optical Arrays of Grazing Incidence Reflectors

International Nuclear Information System (INIS)

Willingale, R.; Feldman, Ch.; Michette, A.; Hart, D.; McFaul, Ch; Morrison, G.R.; Pfauntsch, S.; Powell, A.K.; Sahraei, Sh.; Shand, M.T.; Button, T.; Rodriguez-Sanmartin, D.; Zhang, D.; Dunare, C.; Parkes, W.; Stevenson, T.; Folkard, M.; Vojnovic, B.; Vojnovic, B.

2011-01-01

The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is micro structured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to poly capillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the micro probing of biological cells and tissue samples using Ti Ka radiation (4.5?keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics

Microchannel Methanation Reactors Using Nanofabricated Catalysts, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

Computational Fluid Dynamics Study of Channel Geometric Effect for Fischer-Tropsch Microchannel Reactor

International Nuclear Information System (INIS)

Na, Jonggeol; Jung, Ikhwan; Kshetrimayum, Krishnadash S.; Park, Seongho; Park, Chansaem; Han, Chonghun

2014-01-01

Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been preferred over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent

Coordinate sensitive detectors based on microchannel plates

International Nuclear Information System (INIS)

Gruntman, M.A.

1984-01-01

Coordinate-sensitive detectors (CSD) on the basis of microchannel plates permit to determine in a digital form the coordinates of every recorded particle and they are used in different fields of physical experiment. The sensitive surface diameter of such detectors can reach 10 cm, and spatial resolution - 10 μm. In the review provided CSD with microchannel plates are classified according to the ways of coordinate determination, different types of the detectors, pecUliarities of their design and electron flowsheet are described. It is pointed out that there are reasons for introduction of CSD into practice of laboratory physical investigations in various fields, where the particle recorded is electron or is able to form a secondary electron. It is attributed to nuclear physics, physics of electron and atom collisions, optics, mass-spectrometry, electron microscopy, X-ray analysis, investigation of surfaces

Micro-Channel Embedded Pulsating Heat Pipes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — As the need for thermal control technology becomes more demanding Micro-Channel Embedded Pulsating Heat Pipes (ME-PHPs) represents a sophisticated and enabling...

Distillation process using microchannel technology

Science.gov (United States)

Tonkovich, Anna Lee [Dublin, OH; Simmons, Wayne W [Dublin, OH; Silva, Laura J [Dublin, OH; Qiu, Dongming [Carbondale, IL; Perry, Steven T [Galloway, OH; Yuschak, Thomas [Dublin, OH; Hickey, Thomas P [Dublin, OH; Arora, Ravi [Dublin, OH; Smith, Amanda [Galloway, OH; Litt, Robert Dwayne [Westerville, OH; Neagle, Paul [Westerville, OH

2009-11-03

The disclosed invention relates to a distillation process for separating two or more components having different volatilities from a liquid mixture containing the components. The process employs microchannel technology for effecting the distillation and is particularly suitable for conducting difficult separations, such as the separation of ethane from ethylene, wherein the individual components are characterized by having volatilities that are very close to one another.

Numerical study on boiling heat transfer enhancement in a microchannel heat exchanger

International Nuclear Information System (INIS)

Jeon, Jin Ho; Suh, Young Ho; Son, Gi Hun

2008-01-01

Flow boiling in a microchannel heat exchanger has received attention as an effective heat removal mechanism for high power-density microelectronics. Despite extensive experimental studied, the bubble dynamics coupled with boiling heat transfer in a microchannel heat exchanger is still not well understood due to the technological difficulties in obtaining detailed measurements of microscale two-phase flows. In this study, complete numerical simulations are performed to further clarify the dynamics of flow boiling in a microchannel heat exchanger. The level set method for tracking the liquid-vapor interface is modified to include the effects of phase change and contact angle and to treat an immersed solid surface. Based on the numerical results, the effects of modified channel shape on the bubble growth and heat transfer are quantified

An experimental study on flow friction and heat transfer of water in sinusoidal wavy silicon microchannels

Science.gov (United States)

Huang, Houxue; Wu, Huiying; Zhang, Chi

2018-05-01

Sinusoidal wavy microchannels have been known as a more heat transfer efficient heat sink for the cooling of electronics than normal straight microchannels. However, the existing experimental study on wavy silicon microchannels with different phase differences are few. As a result of this, in this paper an experimental study has been conducted to investigate the single phase flow friction and heat transfer of de-ionized water in eight different sinusoidal wavy silicon microchannels (SWSMCs) and one straight silicon microchannel (SMC). The SWSMCs feature different phase differences (α  =  0 to π) and different relative wavy amplitudes (β  =  A/l  =  0.05 to 0.4), but the same average hydraulic diameters (D h  =  160 µm). It is found that both flow friction constant fRe and the Nusselt number depend on the phase difference and relative wavy amplitude. For sinusoidal wavy microchannels with a relative wavy amplitude (β  =  0.05), the Nusselt number increased noticeably with the phase difference for Re  >  250, but the effect was insignificant for Re  reducing the wavy wave length induced higher pressure drop and apparent friction constant fRe, while the Nusselt number increased with relative wavy amplitude for Re  >  300. The results indicate that the thermal resistances of sinusoidal wavy silicon microchannels were generally lower than that of straight silicon microchannels, and the thermal resistance decreased with the increase in relative wavy amplitude. The enhancement of thermal performance is attributed to the flow re-circulation occurring in the corrugation troughs and the secondary flows or Dean vortices introduced by curved channels. It is concluded that silicon sinusoidal wavy microchannels provide higher heat transfer rate albeit with a higher flow friction, making it a better choice for the cooling of high heat flux electronics.

Estado del arte el diagnóstico y tratamiento del cáncer de mama

Directory of Open Access Journals (Sweden)

C. Soledad Torres, Dra.

2013-07-01

En este capítulo revisaremos las estrategias de diagnóstico por imágenes frente a la sospecha de malignidad. En patología se explican los conceptos más recientes de la clasificación molecular del cáncer de mama y su rol pronóstico y predictivo. En tratamiento locorregional se presentan las alternativas quirúrgicas, de radioterapia y de reconstrucción mamaria según la presentación de la enfermedad. En tratamiento sistémico se señalan las indicaciones de adyuvancia pre y postoperatoria, incluyendo las terapias endocrina, biológica y quimioterapia. En la etapa metastásica se revisan los distintos tratamientos que compatibilizan la prolongación de la supervivencia con la mejor calidad de vida posible. Finalmente presentamos una serie de intervenciones que constituyen el soporte emocional de las pacientes con cáncer de mama.

Use of the μPIV technique for an indirect determination of the microchannel cross-section passage geometry

International Nuclear Information System (INIS)

Puccetti, G; Pulvirenti, B; Morini, G L

2014-01-01

In this work the possible use of the μPIV technique for the experimental determination of the microchannel cross-section geometry has been investigated by means of a blind test in which a series of experimental measurements obtained using glass microchannels having a declared rectangular cross-section with a depth of 100 μm and width of 300 μm and a square microchannel with a 300 μm side have been compared with the direct SEM visualisation of the real cross section of the microchannels. For the (oPIV measurements water is used as working fluid. The laminar fully developed 2D velocity profile has been reconstructed by moving the focal plane of the microscope objective from the bottom to the top of the microchannel. The results shown in this paper demonstrate that the real cross section geometry of the microchannel can be predicted by minimizing the difference between the theoretical and the experimental 2D velocity profiles. When the right passage geometry is determined, the average difference between the theoretical and the experimental velocity is within 4-6%.

UTILIZAÇÃO DE KITS COMO MARCADORES ONCOLÓGICOS PARA O CÂNCER DE MAMA: UMA PROSPECÇÃO TECNOLÓGICA

Directory of Open Access Journals (Sweden)

Antonio Luiz Gomes Júnior

2014-09-01

Full Text Available O câncer de mama é a neoplasia maligna mais comum entre as mulheres e sua taxa de mortalidade ainda é alta. É essencial desenvolver ferramentas de diagnóstico mais sensíveis, que não só complementem a mamografia, mas também permitam a detecção e diagnóstico precoce do câncer de mama, permitindo uma terapia menos invasiva, levando a uma menor morbidade nessas pacientes, ao passo que se torna mais eficaz. O presente trabalho teve como objetivo realizar uma prospecção tecnológica dos kits de identificação de marcados oncológicos para o câncer de mama, por meio da verificação de pedidos de patentes nas bases de dados do Instituto Nacional de Propriedade Industrial (INPI, Organização Mundial de Propriedade Intelectual (WIPO, Banco Europeu de Patente (EPO e no Banco Americano de Marcas e Patentes (USPTO. Após a pesquisa foi constatado que apenas 34 patentes foram encontradas nos bancos de dados analisados, classificandos em classes diferentes, com maior prevalência para a C12Q. Contudo, em relação a aplicabilidade clínica do uso dos marcadores oncológicos no câncer de mama, ainda são necessários consideráveis investimentos para a obtenção de dados provenientes de novos estudos, visto que o câncer é um problema em ascenção.

Imaging microchannel plate detectors for XUV sky survey experiments

International Nuclear Information System (INIS)

Barstow, M.A.; Fraser, G.W.; Milward, S.R.

1986-01-01

Attention is given to the development of microchannel plate detectors for the Wide Field Camera (WFC) XUV (50-300 A) sky survey experiment on Rosat. A novel feature of the detector design is that the microchannel plates and their resistive anode readout are curved to the same radius as the WFC telescope focal surface. It is shown that curving the channel plates is not detrimental to gain uniformity. The paper describes the design of a curved resistive anode readout element and contrasts the present measurements of spatial resolution, global and local uniformity and temperature coefficient of resistance with the poor performance recently ascribed to resistive anodes in the literature. 18 references

The Effect of the Rolling Direction, Temperature, and Etching Time on the Photochemical Machining of Monel 400 Microchannels

Directory of Open Access Journals (Sweden)

Deepakkumar H. Patil

2016-01-01

Full Text Available The present paper describes the effect of the rolling direction on the quality of microchannels manufactured using photochemical machining (PCM of Monel 400. Experiments were carried out to fabricate microchannels along and across the rolling direction to investigate the effect of the grain orientation on microchannel etching. The input parameters considered were channel width and rolling direction, whereas the depth of etch was the response parameters. Different channels of widths of 60, 100, 150, 200, and 250 μm were etched. The effects of the etching time and temperature of the etchant solution on the undercut and depth of the microchannels were studied. For good quality microchannels, the effects of spinning time, spinning speed, exposure time, and photoresist film strength were also taken into consideration. Optimized values of the above were used for the experimentation. The results show that the depth of etch of the microchannel increases more along the rolling direction than across the rolling direction. The channel width and depth are significantly affected by the etching time and temperature. The proposed study reports an improvement in the quality of microchannels produced using PCM.

Cáncer de mama: Diagnóstico temprano (Breast Cancer - Early Diagnosis)

Centers for Disease Control (CDC) Podcasts

2011-04-28

Este podcast responde a la pregunta de una señora del público sobre cómo saber si tiene cáncer de mama.  Created: 4/28/2011 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/1/2011.

Thermal effect of a thermoelectric generator on parallel microchannel heat sink

DEFF Research Database (Denmark)

Kolaei, Alireza Rezania; Rosendahl, Lasse

2012-01-01

Thermoelectric generators (TEG) convert heat energy to electrical power by means of semiconductor charge carriers serving as working fluid. In this work, a TEG is applied to a parallel microchannel heat sink. The effect of the inlet plenum arrangement on the laminar flow distribution...... in the channels is considered at a wide range of the pressure drop along the heat sink. The particular focus of this study is geometrical effect of the TEG on the heat transfer characteristics in the micro-heat sink. The hydraulic diameter of the microchannels is 270 μm, and three heat fluxes are applied...... on the hot surface of the TEG. By considering the maximum temperature limitation for Bi_2 Te_3 material and using the microchannel heat sink for cooling down the TEG system, an optimum pumping power is achieved. The results are in a good agreement with the previous experimental and theoretical studies....

Sono, qualidade de vida e depressão em mulheres no pós-tratamento de câncer de mama

OpenAIRE

Rafihi-Ferreira,Renatha El; Pires,Maria Laura Nogueira; Soares,Maria Rita Zoéga

2012-01-01

Este trabalho investigou a qualidade de sono de mulheres com câncer de mama e suas relações com qualidade de vida e depressão. Cinqüenta mulheres com câncer de mama (grupo clínico) e cinqüenta controles responderam um questionário médico-demográfico e ao instrumento Pittsburgh Sleep Quality Index. O grupo clínico também respondeu aos instrumentos Quality of Life Cancer-Survivor e Brief Zung Self-Rating Depression Scale. Verificou-se que mulheres com câncer tinham significativamente mais queix...

Flow friction and heat transfer of ethanol–water solutions through silicon microchannels

International Nuclear Information System (INIS)

Wu Huiying; Wu Xinyu; Wei Zhen

2009-01-01

An experimental investigation was performed on the flow friction and convective heat transfer characteristics of the ethanol–water solutions flowing through five sets of trapezoidal silicon microchannels having hydraulic diameters ranging from 141.7 µm to 268.6 µm. Four kinds of ethanol–water solutions with the ethanol volume concentrations ranging from 0 to 0.8 were tested under different flow and heating conditions. It was found that the cross-sectional geometric parameters had great effect on the flow friction and heat transfer, and the microchannels with a larger W b /W t (bottom width-to-top width ratio) and a smaller H/W t (depth-to-top width ratio) usually had a larger friction constant and a higher Nusselt number. Entrance effects were significant for the flow friction and heat transfer in silicon microchannels, and decreased with the increase of dimensionless hydrodynamic length L and dimensionless thermal length L + h . When L > 1.0, the hydrodynamic entrance effect on the flow friction was ignorable. For the developed laminar flow in silicon microchannels, the Navier–Stokes equation was applicable. It was also found that the volume concentrations had different effects on the flow friction and heat transfer. Within the experimental range, the effect of volume concentrations on the flow friction was ignorable, and the friction constants of the ethanol–water solutions having different concentrations were the same as those of the pure water. However, volume concentrations had great effect on the convection heat transfer in silicon microchannels. With the increase of the volume concentrations, the Nusselt number of the ethanol–water solutions increased obviously, which was attributed to the combination effect of the increase in the Prantdtl number as well as the volatilization effect of the ethanol. Based on the experimental data, the dimensionless correlations for the flow friction and heat transfer of the ethanol–water solutions in the silicon

Electro-osmotic flows inside triangular microchannels

International Nuclear Information System (INIS)

Vocale, P; Spiga, M; Geri, M; Morini, G L

2014-01-01

This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.

O risco familiar de câncer de mama: a psicanálise diante da pesquisa genética

Directory of Open Access Journals (Sweden)

Luciane Loss Jardim

Full Text Available A Pesquisa Genética está definitivamente na pauta da ciência deste século. Em poucas ocasiões, porém, foi analisada sob a ótica da psicanálise. Este trabalho assume a perspectiva de abordar o risco familiar de câncer de mama pelo viés psicanalítico. Para tal, avalia a posição de quatro mulheres que se submeteram à pesquisa genética desenvolvida, em nível regional, pelo Instituto da Mama do Rio Grande do Sul, vinculado ao Banco Nacional de DNA, com o intuito de verificar a ocorrência de mutação genética responsável pelo câncer de mama hereditário. Aborda as influências tecnológicas na subjetividade e a posição do sujeito frente à hereditariedade, à herança e à enfermidade. Este trabalho de pesquisa é parte de um estudo denominado “Estudo psicanalítico do adoecer de câncer de mama” que , por sua vez fez parte do projeto mais amplo designado como Projeto do Banco Nacional de DNA, executado junto ao Ministério da Saúde.

Numerical investigation of fluid flow and heat transfer under high heat flux using rectangular micro-channels

KAUST Repository

Mansoor, Mohammad M.

2012-02-01

A 3D-conjugate numerical investigation was conducted to predict heat transfer characteristics in a rectangular cross-sectional micro-channel employing simultaneously developing single-phase flows. The numerical code was validated by comparison with previous experimental and numerical results for the same micro-channel dimensions and classical correlations based on conventional sized channels. High heat fluxes up to 130W/cm 2 were applied to investigate micro-channel thermal characteristics. The entire computational domain was discretized using a 120×160×100 grid for the micro-channel with an aspect ratio of (α=4.56) and examined for Reynolds numbers in the laminar range (Re 500-2000) using FLUENT. De-ionized water served as the cooling fluid while the micro-channel substrate used was made of copper. Validation results were found to be in good agreement with previous experimental and numerical data [1] with an average deviation of less than 4.2%. As the applied heat flux increased, an increase in heat transfer coefficient values was observed. Also, the Reynolds number required for transition from single-phase fluid to two-phase was found to increase. A correlation is proposed for the results of average Nusselt numbers for the heat transfer characteristics in micro-channels with simultaneously developing, single-phase flows. © 2011 Elsevier Ltd.

Forced convection flow boiling and two-phase flow phenomena in a microchannel

Science.gov (United States)

Na, Yun Whan

2008-07-01

The present study was performed to numerically analyze the evaporation phenomena through the liquid-vapor interface and to investigate bubble dynamics and heat transfer behavior during forced convective flow boiling in a microchannel. Flow instabilities of two-phase flow boiling in a microchannel were studied as well. The main objective of this research is to investigate the fundamental mechanisms of two-phase flow boiling in a microchannel and provide predictive tools to design thermal management systems, for example, microchannel heat sinks. The numerical results obtained from this study were qualitatively and quantitatively compared with experimental results in the open literature. Physical and mathematical models, accounting for evaporating phenomena through the liquid-vapor interface in a microchannel at constant heat flux and constant wall temperature, have been developed, respectively. The heat transfer mechanism is affected by the dominant heat conduction through the thin liquid film and vaporization at the liquid-vapor interface. The thickness of the liquid film and the pressure of the liquid and vapor phases were simultaneously solved by the governing differential equations. The developed semi-analytical evaporation model that takes into account of the interfacial phenomena and surface tension effects was used to obtain solutions numerically using the fourth-order Runge-Kutta method. The effects of heat flux 19 and wall temperature on the liquid film were evaluated. The obtained pressure drops in a microchannel were qualitatively consistent with the experimental results of Qu and Mudawar (2004). Forced convective flow boiling in a single microchannel with different channel heights was studied through a numerical simulation to investigate bubble dynamics, flow patterns, and heat transfer. The momentum and energy equations were solved using the finite volume method while the liquid-vapor interface of a bubble is captured using the VOF (Volume of Fluid

Inertial effects on heat transfer in superhydrophobic microchannels

Science.gov (United States)

Cowley, Adam; Maynes, Daniel; Crockett, Julie; Iverson, Brian; BYU Fluids Team

2015-11-01

This work numerically studies the effects of inertia on thermal transport in superhydrophbic microchannels. An infinite parallel plate channel comprised of structured superhydrophbic walls is considered. The structure of the superhydrophobic surfaces consists of square pillars organized in a square array aligned with the flow direction. Laminar, fully developed flow is explored. The flow is assumed to be non-wetting and have an idealized flat meniscus. A shear-free, adiabatic boundary condition is used at the liquid/gas interface, while a no-slip, constant heat flux condition is used at the liquid/solid interface. A wide range of Peclet numbers, relative channel spacing distances, and relative pillar sizes are considered. Results are presented in terms of Poiseuille number, Nusselt number, hydrodynamic slip length, and temperature jump length. Interestingly, the thermal transport is varied only slightly by inertial effects for a wide range of parameters explored and compares well with other analytical and numerical work that assumed Stokes flow. It is only for very small relative channel spacing and large Peclet number that inertial effects exert significant influence. Overall, the heat transfer is reduced for the superhydrophbic channels in comparison to classic smooth walled channels. This research was supported by the National Science Foundation (NSF) - United States (Grant No. CBET-1235881).

Cáncer de mama triple negativo: una enfermedad de difícil diagnóstico y tratamiento

Directory of Open Access Journals (Sweden)

Mayer Zaharia

Full Text Available El cáncer de mama triple negativo (CMTN es una neoplasia maligna caracterizada por la ausencia de la expresión de los receptores de estrógeno, de progesterona y HER2. Estudios recientes han señalado que el CMTN es un grupo heterogéneo de distintas neoplasias, con pronósticos diferentes. Sin embargo, debido a que la realización de perfiles genéticos no es una práctica estándar para el diagnóstico convencional del cáncer de mama, se dificulta la apropiada identificación de este subtipo de cáncer de mama. El CMTN se caracteriza por tener patrones epidemiológicos de alta incidencia en poblaciones afroamericanas y latinas, y de menor incidencia en población caucásica y constituye un problema de salud pública por su elevada morbilidad y mortalidad. Ante la ausencia de blancos terapéuticos, la quimioterapia cumple un rol importante en el tratamiento, y muchos esfuerzos están destinándose a buscar otras combinaciones de quimioterapia y nuevas drogas, mientras que las actuales guías no especifican un tratamiento para este tipo de cánceres. En el presente documento se hace una revisión sobre las características epidemiológicas y clínicas, los posibles factores pronósticos y sobre algunas estrategias terapéuticas contra el CMTN.

Uses of microchannel plate intensified detectors for imaging applications in the X-ray, EUV and visible wavelength regions

International Nuclear Information System (INIS)

Read, P.D.; Carter, M.K.; Pike, C.D.; Harrison, R.A.; Kent, B.J.; Swinyard, B.M.; Patchett, B.E.; Redfern, R.M.; Shearer, A.; Colhoun, M.

1997-01-01

The Rutherford Appleton laboratory photon counting detector (RALPCD) has been refined to meet project requirements for a flexible imaging arrangement with applications at X-ray, EUV and visible wavelengths. The basic detector design comprises commercially available high gain microchannel plate intensifiers fibre optically coupled to CID or CCD cameras, to form a modular detector arrangement with the appropriate RAL detection and centroiding software. Frames of data from the cameras are detected and centroided in a transputer or C40 parallel processor array where correction algorithms use look up tables to produce pattern free images at high resolution. Data from completed applications are used to illustrate the performance and future advances are discussed. (orig.)

One-dimensional position readout from microchannel plates

International Nuclear Information System (INIS)

Connell, K.A.; Przybylski, M.M.

1982-01-01

The development of a one-dimensional position readout system with microchannel plates, is described, for heavy ion detectors for use in a particle time-of-flight telescope and as a position sensitive device in front of an ionisation counter at the Nuclear Structure Facility. (U.K.)

Cooling Performance of Additively Manufactured Microchannels and Film Cooling Holes

Science.gov (United States)

Stimpson, Curtis K.

Additive manufacturing (AM) enables fabrication of components that cannot be made with any other manufacturing method. Significant advances in metal-based AM systems have made this technology feasible for building production parts to be used use in commercial products. In particular, the gas turbine industry benefits from AM as a manufacturing technique especially for development of components subjected to high heat flux. It has been shown that the use of microchannels in high heat flux components can lead to more efficient cooling designs than those that presently exist. The current manufacturing methods have prevented the use of microchannels in such parts, but AM now makes them manufacturable. However, before such designs can become a reality, much research must be done to characterize impacts on flow and heat transfer of AM parts. The current study considers the effect on flow and heat transfer through turbine cooling features made with AM. Specifically, the performance of microchannels and film cooling holes made with laser powder bed fusion (L-PBF) is assessed. A number of test coupons containing microchannels were built from high temperature alloy powders on a commercially available L-PBF machine. Pressure drop and heat transfer experiments characterized the flow losses and convective heat transfer of air passing through the channels at various Reynolds numbers and Mach numbers. The roughness of the channels' surfaces was characterized in terms of statistical roughness parameters; the morphology of the roughness was examined qualitatively. Magnitude and morphology of surface roughness found on AM parts is unlike any form of roughness seen in the literature. It was found that the high levels of roughness on AM surfaces result in markedly augmented pressure loss and heat transfer at all Reynolds numbers, and conventional flow and heat transfer correlations produce erroneous estimates. The physical roughness measurements made in this study were correlated to

Numerical study of the bubbly flow regime in micro-channel flow boiling

Science.gov (United States)

Bhuvankar, Pramod; Dabiri, Sadegh

2017-11-01

Two-phase flow accompanied by boiling in micro-channel heat sinks is an effective means for heat removal from computer chips. We present a numerical study of flow boiling in micro-channels with conjugate heat transfer with a focus on the bubbly flow regime. The bubbles are assumed to nucleate at a pre-determined location and frequency. The Navier Stokes equations are solved using a single fluid formulation with the Front tracking method. Phase change is implemented using the deficit in heat flux across the bubble interface. The analytical solution for bubble growth in a superheated liquid is used as a benchmark to validate the mentioned numerical method. Water and FC-72 are studied as the operating fluids in a micro-channel made of Copper with a focus on hotspot mitigation. The micro-channel of cross-section 231 μm × 1000 μm , is used to study the effects of vertical up-flow, vertical down-flow and horizontal flow of the mentioned fluids on the heat transfer coefficients. A simple film model accounting for mass and energy conservation is applied wherever the bubble approaches closer than a cell width to the wall. The results of the simulation are compared with existing experimental data for bubble growth rates and heat transfer coefficients.

Deactivation of Legionella Pneumophila in municipal wastewater by ozone generated in arrays of microchannel plasmas

Science.gov (United States)

Dong, Shengkun; Li, Jun; Kim, Min-Hwan; Cho, Jinhoon; Park, Sung-Jin; Nguyen, Thanh H.; Eden, J. Gary

2018-06-01

A greater than four log10 reduction in the concentration of Legionella pneumophila in municipal wastewater has been achieved in 1 min with ozone produced by a microchannel plasma reactor. Requiring less than 22 W of electrical power, and ambient air as the feedstock gas, the microplasma ozone generator is robust and a promising alternative to conventional corona and dielectric barrier discharge (DBD) technologies. Contrary to previous studies, the Ct model for pathogen deactivation (i.e. rate proportional to the product of the available disinfectant concentration and the exposure duration) is found to be valid for L. pneumophila. Accordingly, wastewater-specific Ct equations have been developed to predict the deactivation of L. pneumophila in the secondary wastewater environment. Inactivation of this pathogen was found to be dependent on temperature only in the absence of wastewater organic matter (WOM). In the presence of WOM, pathogen deactivation is controlled by the disinfection contact time, initial ozone concentration (varied between 15 and 281 µg l‑1), and initial WOM loading. The data reported here will assist in the implementation of plasma ozone generators for L. pneumophila deactivation in cooling towers, point-of-use systems, and wastewater reclamation facilities.

Flow and heat transfer behaviour of nanofluids in microchannels

Directory of Open Access Journals (Sweden)

James Bowers

2018-04-01

Full Text Available Flow and heat transfer of aqueous based silica and alumina nanofluids in microchannels were experimentally investigated. The measured friction factors were higher than conventional model predictions at low Reynolds numbers particularly with high nanoparticle concentrations. A decrease in the friction factor was observed with increasing Reynolds number, possibly due to the augmentation of nanoparticle aggregate shape arising from fluid shear and alteration of local nanoparticle concentration and nanofluid viscosity. Augmentation of the silica nanoparticle morphology by fluid shear may also have affected the friction factor due to possible formation of a core/shell structure of the particles. Measured thermal conductivities of the silica nanofluids were in approximate agreement with the Maxwell-Crosser model, whereas the alumina nanofluids only showed slight enhancements. Enhanced convective heat transfer was observed for both nanofluids, relative to their base fluids (water, at low particle concentrations. Heat transfer enhancement increased with increasing Reynolds number and microchannel hydraulic diameter. However, the majority of experiments showed a larger increase in pumping power requirements relative to heat transfer enhancements, which may hinder the industrial uptake of the nanofluids, particularly in confined environments, such as Micro Electro-Mechanical Systems (MEMS. Keywords: Nanofluid, Microchannel, Heat transfer, Pressure drop, Friction factor, Thermal conductivity, Viscosity

Effect of supersaturation on L-glutamic acid polymorphs under droplet-based microchannels

Science.gov (United States)

Jiang, Nan; Wang, Zhanzhong; Dang, Leping; Wei, Hongyuan

2016-07-01

Supersaturation is an important controlling factor for crystallization process and polymorphism. Droplet-based microchannels and conventional crystallization were used to investigate polymorphs of L-gluatamic acid in this work. The results illustrate that it is easy to realize the accurate and rapid control of the crystallization temperature in the droplets, which is especially beneficial to heat and mass transfer during crystallization. It is also noted that higher degree of supersaturation favors the nucleation of α crystal form, while lower degree of supersaturation favors the nucleation of β crystal form under droplet-based microchannels for L-gluatamic acid. In addition, there is a different nucleation behavior to be found under droplet-based microchannels both for the β form and α form of L-glutamic acid. This new finding can provide important insight into the development and design of investigation meanings for drug polymorph.

Câncer de mama: sentimentos e percepções das mulheres diante do diagnóstico / Breast cancer: feelings and perceptions of women before the diagnosis

Directory of Open Access Journals (Sweden)

Keli Regiane Tomeleri da Fonseca Pinto

2018-04-01

Full Text Available Objetivo: Conhecer os sentimentos e percepções das mulheres diante o diagnóstico de câncer de mama. Métodos: Trata-se de um estudo qualitativo, realizado no Ambulatório de Oncologia de um Hospital Universitário, junto à 11 mulheres com câncer de mama e idade entre 43 e 58 anos. A coleta de dados foi realizada por meio de entrevista semiestruturada, entre maio a julho de 2015. Os dados foram analisados e interpretados conforme a análise de conteúdo. Resultados: Após a análise emergiram quatro categorias: esperando pelo diagnóstico; sentimentos despertados após o diagnóstico; o apoio familiar; viver e orar após o diagnóstico de câncer de mama. Conclusão: O estudo mostrou que as mulheres já esperavam o diagnóstico de câncer, porém, mesmo dizendo estarem preparadas para tal diagnóstico, diante da notícia se sentiram aflitas, receberam apoio da família e também buscaram apoio religioso para enfrentar o difícil momento do diagnóstico do câncer de mama.

Synthesis and evaluation of a {sup 99m}Tc-MAMA-propyl-thymidine complex as a potential probe for in vivo visualization of tumor cell proliferation with SPECT

Energy Technology Data Exchange (ETDEWEB)

Celen, Sofie [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium); Groot, Tjibbe de [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Balzarini, Jan [Rega Institute for Medical Research, K.U. Leuven, B-3000 Leuven (Belgium); Vunckx, Kathleen [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Terwinghe, Christelle [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Vermaelen, Peter [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Van Berckelaer, Lizette [Rega Institute for Medical Research, K.U. Leuven, B-3000 Leuven (Belgium); Vanbilloen, Hubert [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Nuyts, Johan [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Mortelmans, Luc [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Verbruggen, Alfons [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium); Bormans, Guy [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium)]. E-mail: guy.bormans@pharm.kuleuven.be

2007-04-15

Introduction: Cytosolic thymidine kinase (TK1) catalyzes phosphorylation of thymidine to its monophosphate. TK1 activity is closely related with DNA synthesis, and thymidine analogs derivatized with bulky carboranylalkyl groups at the N-3 position were reported to be good substrates for TK1. Accordingly, we have synthesized {sup 99m}Tc-MAMA-propyl-thymidine and evaluated it as a potential tumor tracer. Methods: The bis(S-trityl)-protected MAMA-propyl-thymidine precursor (3-N-[S-trityl-2-mercaptoethyl]-N-[N'-(S-trityl-2-mercaptoethyl) amidoacetyl] -aminopropyl-thymidine) was prepared in three steps, and its structure was confirmed with {sup 1}H NMR and mass spectrometry. Deprotection of the thiols and labeling with {sup 99m}Tc were done in a two-step, one-pot procedure, yielding {sup 99m}Tc-MAMA-propyl-thymidine, which was analyzed with high-performance liquid chromatography, radio-LC-MS analysis (ESI+) and electrophoresis, and its log P was determined. The biodistribution in normal mice was evaluated, and its biodistribution in a radiation-induced fibrosarcoma (RIF) tumor mouse was compared with that of 3'-deoxy-3'-[{sup 18}F] fluorothymidine [{sup 18}F]FLT. Results: {sup 99m}Tc-MAMA-propyl-thymidine was obtained with a radiochemical yield of 70%. Electrophoresis indicated that the complex is uncharged, and its log P was 1.0. The molecular ion mass of the Tc complex was 589 Da, which is compatible with the hypothesized N{sub 2}S{sub 2}-oxotechnetium structure. Tissue distribution showed fast clearance from plasma primarily by the hepatobiliary pathway. Whole-body planar imaging after injection of {sup 99m}Tc-MAMA-propyl-thymidine in an RIF tumor-bearing mouse showed high uptake in the liver and the intestines. No uptake was observed in the tumor, in contrast to the clear uptake observed for [{sup 18}F] FLT visualized with {mu}PET. Conclusions: Although it has been reported that TK1 accepts large substituents at the N-3 position of the thymine ring

Comparison of heat pump performance using fin-and-tube and microchannel heat exchangers under frost conditions

International Nuclear Information System (INIS)

Shao, Liang-Liang; Yang, Liang; Zhang, Chun-Lu

2010-01-01

Vapor compression heat pumps are drawing more attention in energy saving applications. Microchannel heat exchangers can provide higher performance via less core volume and reduce system refrigerant charge, but little is known about their performance in heat pump systems under frosting conditions. In this study, the system performance of a commercial heat pump using microchannel heat exchangers as evaporator is compared with that using conventional finned-tube heat exchangers numerically and experimentally. The microchannel and finned-tube heat pump system models used for comparison of the microchannel and finned-tube evaporator performance under frosting conditions were developed, considering the effect of maldistribution on both refrigerant and air sides. The quasi-steady-state modeling results are in reasonable agreement with the test data under frost conditions. The refrigerant-side maldistribution is found remarkable impact on the microchannel heat pump system performance under the frost conditions. Parametric study on the fan speed and the fin density under frost conditions are conducted as well to figure out the best trade-off in the design of frost tolerant evaporators. (author)

Estudio de casos y controles de marcadores sanguíneos para el diagnóstico precoz de cáncer de mama

OpenAIRE

Bayo Calero, Juan Lucas

2016-01-01

En el mundo desarrollado, el cáncer de mama es la neoplasia femenina más frecuente y que causa más mortalidad. Los programas de detección precoz contribuyen a un diagnóstico temprano de la enfermedad y por tanto a mejorar la supervivencia de la misma. No existen marcadores tumorales específicos para la fase precoz del cáncer de mama; si existiera alguno eficaz, podría servir de apoyo al screening radiológico. Sin embargo, ya en la fase de estudio clínico y diagnóstico final, se solicitan much...

Transition from annular flow to plug/slug flow in condensation of steam in microchannels

Energy Technology Data Exchange (ETDEWEB)

Quan, Xiaojun; Cheng, Ping; Wu, Huiying [School of Mechanical and Power Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Shanghai 200240 (China)

2008-02-15

A visualization study has been conducted to investigate the transition from annular flow to plug/slug flow in the condensation of steam in two different sets of parallel microchannels, having hydraulic diameters of 90 {mu}m and 136 {mu}m, respectively. The steam in the parallel microchannels was cooled on the bottom by forced convection of water and by natural convection of air from the top. It is found that the location, where the transition from annular flow to plug/slug flow takes place, depends on mass flux and cooling rate of steam. The effects of mass flux and cooling rate on the occurrence frequency of the injection flow in a single microchannel, having a hydraulic diameter of 120 {mu}m and 128 {mu}m, respectively, are investigated. It is found that two different shapes of injection flow occur in the smooth annular flow in microchannels: injection flow with unsteady vapor ligament occurring at low mass flux (or high cooling rate) and injection flow with steady vapor ligament occurring at high mass flux (or low cooling rate). It is also found that increase of steam mass flux, decrease of cooling rate, or decrease of the microchannel diameter tends to enhance instability of the condensate film on the wall, resulting in occurrence of the injection flow further toward the outlet with an increase in occurrence frequency. (author)

In vitro blood flow in a rectangular PDMS microchannel: experimental observations using a confocal micro-PIV system.

Science.gov (United States)

Lima, Rui; Wada, Shigeo; Tanaka, Shuji; Takeda, Motohiro; Ishikawa, Takuji; Tsubota, Ken-ichi; Imai, Yohsuke; Yamaguchi, Takami

2008-04-01

Progress in microfabricated technologies has attracted the attention of researchers in several areas, including microcirculation. Microfluidic devices are expected to provide powerful tools not only to better understand the biophysical behavior of blood flow in microvessels, but also for disease diagnosis. Such microfluidic devices for biomedical applications must be compatible with state-of-the-art flow measuring techniques, such as confocal microparticle image velocimetry (PIV). This confocal system has the ability to not only quantify flow patterns inside microchannels with high spatial and temporal resolution, but can also be used to obtain velocity measurements for several optically sectioned images along the depth of the microchannel. In this study, we investigated the ability to obtain velocity measurements using physiological saline (PS) and in vitro blood in a rectangular polydimethysiloxane (PDMS) microchannel (300 microm wide, 45 microm deep) using a confocal micro-PIV system. Applying this combination, measurements of trace particles seeded in the flow were performed for both fluids at a constant flow rate (Re = 0.02). Velocity profiles were acquired by successive measurements at different depth positions to obtain three-dimensional (3-D) information on the behavior of both fluid flows. Generally, the velocity profiles were found to be markedly blunt in the central region, mainly due to the low aspect ratio (h/w = 0.15) of the rectangular microchannel. Predictions using a theoretical model for the rectangular microchannel corresponded quite well with the experimental micro-PIV results for the PS fluid. However, for the in vitro blood with 20% hematocrit, small fluctuations were found in the velocity profiles. The present study clearly shows that confocal micro-PIV can be effectively integrated with a PDMS microchannel and used to obtain blood velocity profiles along the full depth of the microchannel because of its unique 3-D optical sectioning ability

FIBROMATOSIS (DESMOID TUMOR OF THE BREAST. Fibromatosis (tumor desmoide de mama

Directory of Open Access Journals (Sweden)

Zhaneta P Boceska

2016-03-01

Full Text Available El tumor desmoide (fibromatosis es una entidad patológica extremadamente rara que se desarrolla de la fascia muscular y la aponeusorsis. Aunque sin potencial metastático, estos tumores son localmente muy agresivos y tienden a infiltrarse en los tejidos circundantes. Nosotros presentamos un caso de tumour desmoide de mama, que tuvo apariencias clínicas sugestivas a carcinoma. La paciente, de 56 años presentó una masa palpable de mama derecho. La citología por aspiracion con aguja fina (AGF no detectó ninguna célula maligna, por lo que se hizo una escisión local conservadora. La paciente no recibió ningun tratamiento postoperatorio adicional, y continúa viva y sana en los siguientes 18 meses. Desmoid tumor (fibromatosis is extremely rare benign pathological entity that develops from muscular fasciae and aponeuroses. Although without metastatic potential, these tumors are locally very aggressive and tend to infiltrate the surrounding tissues. We present a case of a desmoid tumor of the breast that had clinical appearance suggestive of carcinoma. The patient was 56 years old female with a previous history of surgical trauma who presented with a palpable mass in the right breast. A fine needle aspiration (FNA cytology did not reveal any malignant cells, thus conservative local excision was performed. The patient did not receive any additional postoperative treatment and was alive and free of disease after 18 months of follow-up. 

Effect of wall pattern configurations on Stokes flow through a microchannel with superhydrophobic slip

Science.gov (United States)

Mak, H. M.; Ng, C. O.

2010-11-01

The present work aims to study low-Reynolds-number flow through a microchannel with superhydrophobic surfaces, which contain a periodic array of parallel ribs on the upper and lower walls. Mimicking impregnation, the liquid is allowed to penetrate the grooves between the ribs which are filled with an inviscid gas. The array of ribs and grooves gives a heterogeneous wall boundary condition to the channel flow, with partial-slip boundary condition on the solid surface and no-shear boundary condition on the liquid-gas interface. Using the method of eigenfunction expansions and domain decomposition, semi-analytical models are developed for four configurations. Two of them are for longitudinal flow and the others are for transverse flow. For each flow orientation, in-phase and out-phase alignments of ribs between the upper and lower walls are analyzed. The effect of the phase alignments of ribs is appreciable when the channel height is sufficiently small. In-phase alignment gives rise to a larger effective slip length in longitudinal flow. On the contrary, out-phase alignment will yield a larger effective slip length in transverse flow. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China, through Project HKU 7156/09E.

Pesquisaje de cáncer de mama en la comunidad de Santos Suárez

Directory of Open Access Journals (Sweden)

Marianela Prendes Labrada

1998-04-01

Full Text Available Se realiza un estudio descriptivo en 3 consultorios del área del Policlínico "Santos Suárez" en el año 1996 con el objetivo de determinar la incidencia de cáncer de mama y la utilización de métodos de detección precoz. Se informa que la muestra estuvo constituida por 600 mujeres mayores de 20 años seleccionadas al azar a las cuales se les hizo el pesquisaje y se les aplicó una encuesta. Se encuentra que la incidencia de cáncer mamario fue del 3 %. El 22,5 % de las mujeres se clasificaron como de alto riesgo de padecer el cáncer y el 83,3 % de los cánceres mamarios se detectaron en mujeres con alto riesgo y más de 50 años. Se señala que el 58,2 % de la muestra no conoce el autoexamen de mama y el 64 % no lo practica. Al 45,1 % de las mujeres nunca se le había realizado el examen clínico de las mamasA descriptive study of 3 physicians'offices from Santos Suárez polyclinic was carried out in 1996 aimed at determining the incidence of breast cancer and the use of early diagnosis methods. It is stressed that 600 randomly chosen women over 20 were included in the sample, who were screened and applied a survey. The breast cancer incidence rate was 3 %. 22.5 % of sampled women was clasified as high breast cancer risk subjects whereas 83.3 % of detected breast cancer was found in high risk women over 50. 58.2 % of them has no idea about the breast self-examination and 64 % does not put it into practice. 45.1 % of women has never been breast-screened before

Tumour metastasis-associated gene profiling using one-dimensional microfluidic beads array

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

Great efforts have been made on the early diagnosis and molecular mechanism research of tumour metastasis in recent years. In this paper, based on the one-dimensional microfluidic beads array, a novel platform for tumour metastasis-associated genes profiling has been developed by depositing nucleic acids functional beads in the microchannel. This platform is sensitive (limit of detection: 0.02 nmol/L) and can perform mRNAs analysis without PCR. Two human colon cancer cell lines (primary and metastatic) from the same patient were used as a model, and transcriptional expression profiling of multiple tumour metastasis-associated genes in these two cell lines was successfully achieved. Furthermore, the results obtained on the beads array were validated by RT-PCR. This novel beads array has advantages of high sensitivity, little sample consumption, short assay time, low cost and high throughput capability. It holds the potential in early diagnosis and mechanism research of tumour metastasis.

Optimization of porous microchannel heat exchanger

Science.gov (United States)

Kozhukhov, N. N.; Konovalov, D. A.

2017-11-01

The technical progress in information and communication sphere leads to a sharp increase in the use of radio electronic devices. Functioning of radio electronics is accompanied by release of thermal energy, which must be diverted from the heat-stressed element. Moreover, using of electronics at negative temperatures, on the contrary, requires supply of a certain amount of heat to start the system. There arises the task of creating a system that allows both to supply and to divert the necessary amount of thermal energy. The development of complex thermostabilization systems for radio electronic equipment is due to increasing the efficiency of each of its elements separately. For more efficient operation of a heat exchanger, which directly affects the temperature of the heat-stressed element, it is necessary to calculate the mode characteristics and to take into account the effect of its design parameters. The results of optimizing the microchannel heat exchanger are presented in the article. The target optimization functions are the mass, pressure drop and temperature. The parameters of optimization are the layout of porous fins, their geometric dimensions and coolant flow. For the given conditions, the optimum variant of porous microchannel heat exchanger is selected.

Oscillatory electroosmotic flow in a parallel-plate microchannel under asymmetric zeta potentials

Science.gov (United States)

Peralta, M.; Arcos, J.; Méndez, F.; Bautista, O.

2017-06-01

In this work, we conduct a theoretical analysis of the start-up of an oscillatory electroosmotic flow (EOF) in a parallel-plate microchannel under asymmetric zeta potentials. It is found that the transient evolution of the flow field is controlled by the parameters {R}ω , {R}\\zeta , and \\bar{κ }, which represent the dimensionless frequency, the ratio of the zeta potentials of the microchannel walls, and the electrokinetic parameter, which is defined as the ratio of the microchannel height to the Debye length. The analysis is performed for both low and high zeta potentials; in the former case, an analytical solution is derived, whereas in the latter, a numerical solution is obtained. These solutions provide the fundamental characteristics of the oscillatory EOFs for which, with suitable adjustment of the zeta potential and the dimensionless frequency, the velocity profiles of the fluid flow exhibit symmetric or asymmetric shapes.

Novel dense CO2 technique for beta-galactosidase immobilization in polystyrene microchannels.

Science.gov (United States)

Leclair Ellis, Jeffrey; Tomasko, David L; Dehghani, Fariba

2008-03-01

In this study we design new fabrication techniques and demonstrate the potential of using dense CO2 for facilitating crucial steps in the fabrication of polymeric lab-on-a-chip microdevices by embedding biomolecules at temperatures well below the polymer's glass transition temperature (T(g)). These new techniques are environmentally friendly and done without the use of a clean room. Carbon dioxide at 40 degrees C and between 4.48 and 6.89 MPa was used to immobilize the biologically active molecule, beta-galactosidase (beta-gal), on the surface of polystyrene microchannels. To our knowledge, this is the first time dense CO2 has been used to directly immobilize an enzyme in a microchannel. beta-gal activity was maintained and shown via a fluorescent reaction product, after enzyme immobilization and microchannel capping by the designed fabrication steps at 40 degrees C and pressures up to 6.89 MPa.

Flow and Heat Transfer in Cooling Microchannels with Phase-Change

Energy Technology Data Exchange (ETDEWEB)

Peles, Y P; Yarin, L P; Hetsroni, G [Technion, Israel Institute of Technology, Haifa (Israel) Faculty of Engineering

1998-05-19

The subject of the present work is the parametrical investigation of hydrodynamic and thermal characteristics of laminar flow with phase-change in a heating microchannels. The study is based on the quasi-one-dimensional model of non-isothermal capillary flow. This model takes into account the evolution of flow, heating and evaporation of the liquid, as well as the influence of capillary, inertia, friction and gravity forces. The effect of various parameters (sizes of microchannel, initial temperature of cooling liquid, wall heat flux etc.) on hydrodynamic and thermal structures of the flow, the length of heating, evaporation and superheat regions is studied. Thc specific features of the phenomena is discussed.

Flow and Heat Transfer in Cooling Microchannels with Phase-Change

International Nuclear Information System (INIS)

Peles, Y.P.; Yarin, L.P.; Hetsroni, G.

1998-01-01

The subject of the present work is the parametrical investigation of hydrodynamic and thermal characteristics of laminar flow with phase-change in a heating microchannels. The study is based on the quasi-one-dimensional model of non-isothermal capillary flow. This model takes into account the evolution of flow, heating and evaporation of the liquid, as well as the influence of capillary, inertia, friction and gravity forces. The effect of various parameters (sizes of microchannel, initial temperature of cooling liquid, wall heat flux etc.) on hydrodynamic and thermal structures of the flow, the length of heating, evaporation and superheat regions is studied. Thc specific features of the phenomena is discussed

Measuring the 3D motion of particles in microchannel acoustophoresis using astigmatism particle tracking velocimetry

DEFF Research Database (Denmark)

Augustsson, P.; Barnkob, Rune; Bruus, Henrik

2012-01-01

We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis are exami...... relative to the influence from the acoustic radiation force. The current study opens the route to optimized acoustophoretic system design and operation to enable manipulation of small biological components such as spores, bacteria and viruses.......We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis...... are examined in three dimensions. We have quantified the velocity of particles driven by the primary acoustic radiation force and acoustic streaming, respectively, using 0.5-μm and 5-μm particles. Increased ultrasound frequency and lowered viscosity of the medium reduced the influence of acoustic streaming...

Continuous particle focusing in a waved microchannel using negative dc dielectrophoresis

KAUST Repository

Li, Ming

2012-07-26

We present a waved microchannel for continuous focusing of microparticles and cells using negative direct current (dc) dielectrophoresis. The waved channel is composed of consecutive s-shaped curved channels in series to generate an electric field gradient required for the dielectrophoretic effect. When particles move electrokinetically through the channel, the experienced negative dielectrophoretic forces alternate directions within two adjacent semicircular microchannels, leading to a focused continuous-flow stream along the channel centerline. Both the experimentally observed and numerically simulated results of the focusing performance are reported, which coincide acceptably in proportion to the specified dimensions (i.e. inlet and outlet of the waved channel). How the applied electric field, particle size and medium concentration affect the performance was studied by focusing polystyrene microparticles of varying sizes. As an application in the field of biology, the focusing of yeast cells in the waved mcirochannel was tested. This waved microchannel shows a great potential for microflow cytometry applications and is expected to be widely used before different processing steps in lab-on-A-chip devices with integrated functions. © 2012 IOP Publishing Ltd.

Conceito de risco para câncer de mama em pesquisas de enfermagem Concepto de riesgo para cáncer de mama en investigaciones de enfermería Concept of risk for breast cancer in nursing research

Directory of Open Access Journals (Sweden)

Anna Paula Sousa da Silva

2011-01-01

Full Text Available OBJETIVO: Analisar o conceito de risco em pesquisas sobre câncer de mama na área da Enfermagem. MÉTODOS: O estudo seguiu a metodologia de análise conceitual proposta por Walker e Avant. e foi desenvolvido por meio de consulta às bases de dados SCOPUS e CINAHL. A seleção foi realizada pelos critérios de inclusão e exclusão, constituindo uma amostra de 12 artigos. RESULTADOS: Foram identificados os principais usos do conceito de risco, atributos definidores, antecedentes e consequentes do conceito. CONCLUSÃO: A avaliação do conceito de risco para câncer de mama possibilitou uma compreensão mais ampla do fenômeno, com destaque para a detecção precoce da doença e a vulnerabilidade de pacientes com risco de desenvolver a neoplasia.OBJETIVO: Analizar el concepto de riesgo en investigaciones sobre cáncer de mama en el área de la Enfermería. MÉTODOS: El estudio siguió la metodología de análisis conceptual propuesta por Walker y Avant, desarrollado por medio de consulta a las bases de datos SCOPUS y CINAHL. La selección fue realizada por los criterios de inclusión y exclusión, constituindo una muestra de 12 artículos. RESULTADOS: Fueron identificados los principales usos del concepto de riesgo, atributos definidores, antecedentes y consecuentes del concepto. CONCLUSIÓN: La evaluación del concepto de riesgo para cáncer de mama posibilitó una comprensión más amplia del fenómeno, especialmente para la detección precoz de la enfermedad y la vulnerabilidad de pacientes con riesgo de desarrollar la neoplasia.OBJECTIVE: To analyze the concept of risk for breast cancer in research in the nursing discipline. METHODS: The study followed the methodology of conceptual analysis proposed by Walker and Avant, and was conducted using the databases SCOPUS and CINAHL. The selection was made using exclusionary and inclusionary criteria, resulting in a sample of 12 articles. RESULTS: We identified the principle uses of the concept of

Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask

Science.gov (United States)

Prakash, Shashi; Kumar, Subrata

2017-09-01

CO2 lasers are commonly used for fabricating polymer based microfluidic devices. Despite several key advantages like low cost, time effectiveness, easy to operate and no requirement of clean room facility, CO2 lasers suffer from few disadvantages like thermal bulging, improper dimensional control, difficulty to produce microchannels of other than Gaussian cross sectional shapes and inclined surface walls. Many microfluidic devices require square or rectangular cross-sections which are difficult to produce using normal CO2 laser procedures. In this work, a thin copper sheet of 40 μm was used as a mask above the PMMA (Polymethyl-methacrylate) substrate while fabricating the microchannels utilizing the raster scanning feature of the CO2 lasers. Microchannels with different width dimensions were fabricated utilizing a CO2 laser in with mask and without-mask conditions. A comparison of both the fabricating process has been made. It was found that microchannels with U shape cross section and rectangular cross-section can efficiently be produced using the with mask technique. In addition to this, this technique can provide perfect dimensional control and better surface quality of the microchannel walls. Such a microchannel fabrication process do not require any post-processing. The fabrication of mask using a nanosecond fiber laser has been discussed in details. An underwater laser fabrication method was adopted to overcome heat related defects in mask preparation. Overall, the technique was found to be easy to adopt and significant improvements were observed in microchannel fabrication.

X-ray radiation channeling in micro-channel plates: Spectroscopy with a synchrotron radiation beam

International Nuclear Information System (INIS)

Mazuritskiy, M.I.; Dabagov, S.B.; Marcelli, A.; Dziedzic-Kocurek, K.; Lerer, A.M.

2015-01-01

We present here the angular distribution of the radiation propagated inside MultiChannel Plates with micro-channels of ∼3 μm diameter. The spectra collected at the exit of the channels present a complex distribution with contributions that can be assigned to the fluorescence radiation, originated from the excitation of the micro-channel walls. For radiation above the absorption edge, when the monochromatic energy in the region of the Si L-edge hits the micro-channel walls with a grazing angle θ ⩾ 5°, or at the O K-edge when θ ⩾ 2° a fluorescence radiation is detected. Additional information associated to the fine structures of the XANES spectra detected at the exit of MCPs are also presented and discussed

Experimental investigation of Cu-based, double-layered, microchannel heat exchangers

International Nuclear Information System (INIS)

Lu, Bin; Meng, W J; Mei, Fanghua

2013-01-01

Cu-based, single- and double-layered, microchannel heat exchangers (MHEs) were fabricated and assembled. Comparative measurements on liquid flow characteristics and heat transfer performance were conducted on these devices. Results were compared at the individual microchannel level as well as at the device level. The present results demonstrate that double-layered MHEs exhibit similar heat transfer performance while suffering a much lower pressure drop penalty compared to single-layered MHEs. Another Cu-based, double-layered, liquid–liquid counter-flow MHE was fabricated, assembled and tested. Results show that a low-volume, multilayered, high-performance, liquid-to-liquid MHE is achievable following the manufacturing protocols of the present double-layered, liquid–liquid counter-flow MHE. (paper)

Development of a Microchannel In Situ Propellant Production System

Energy Technology Data Exchange (ETDEWEB)

Brooks, Kriston P.; Rassat, Scot D.; TeGrotenhuis, Ward E.

2005-09-01

An in situ propellant production (ISPP) plant on future Mars robotic missions can produce oxygen (O2) and methane (CH4) that can be used for propellant for the return voyage. By producing propellants from Mars atmospheric carbon dioxide (CO2) and hydrogen (H2) brought from Earth, the initial mass launched in low Earth orbit can be reduced by 20% to 45%, as compared to carrying all of the propellant for a round-trip mission to the Mars surface from Earth. Pacific Northwest National Laboratory used microchannel architecture to develop a Mars-based In Situ Propellant Production (ISPP) system. This three year research and development effort focused on process intensification and system miniaturization of three primary subsystems: a thermochemical compressor, catalytic reactors, and components for separating gas phases from liquid phases. These systems were designed based on a robotic direct return mission scenario, but can be scaled up to human flight missions by simply numbering up the microchannel devices. The thermochemical compression was developed both using absorption and adsorption. A multichannel adsorption system was designed to meet the full-scale CO2 collection requirements using temperature swing adsorption. Each stage is designed to achieve a 10x compression of CO2. A compression ratio to collect Martian atmospheric CO2 at ~0.8 kPa and compress it to at least 100 kPa can be achieved with two adsorption stages in series. A compressor stage incorporates eight thermally coupled adsorption cells at various stages in the adsorption/desorption cycle to maximize the recuperation of thermal energy and provide a nearly continuous flow of CO2 to the downstream reactors. The thermochemically compressed CO2 is then mixed with hydrogen gas and fed to two reactors: a Sabatier Reaction unit and a Reverse Water/Gas Shift unit. The microchannel architecture allows better heat control than is possible in an adiabatic system, resulting in significantly higher conversion. The

Descripci??n del dolor y el tono vagal en mujeres supervivientes de c??ncer de mama y efectos f??sicos de un programa de fisioterapia acu??tica

OpenAIRE

Caro Mor??n, Elena

2015-01-01

El diagn??stico precoz, los avances en los tratamientos y la prevenci??n de la recurrencia son factores responsables del aumento de la supervivencia en las pacientes de c??ncer de mama. Estas pacientes sufren numerosas secuelas o trastornos cr??nicos relacionados con la propia enfermedad o derivadas de los tratamientos recibidos que repercuten sobre su calidad de vida. Las mujeres supervivientes de c??ncer de mama (SCM), objeto de nuestro estudio, presentan disfunciones card??a...

Direct simulation Monte Carlo method for gas flows in micro-channels with bends with added curvature

Directory of Open Access Journals (Sweden)

Tisovský Tomáš

2017-01-01

Full Text Available Gas flows in micro-channels are simulated using an open source Direct Simulation Monte Carlo (DSMC code dsmcFOAM for general application to rarefied gas flow written within the framework of the open source C++ toolbox called OpenFOAM. Aim of this paper is to investigate the flow in micro-channel with bend with added curvature. Results are compared with flows in channel without added curvature and equivalent straight channel. Effects of micro-channel bend was already thoroughly investigated by White et al. Geometry proposed by White is also used here for refference.

Microchannel Reactors for ISRU Applications Using Nanofabricated Catalysts, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and USRA propose to develop microchannel reactors for In-Situ Resources Utilization (ISRU) using nanofabricated catalysts. The proposed...

A simple process to achieve microchannels geometries able to produce hydrodynamic cavitation

Science.gov (United States)

Qiu, X.; Cherief, W.; Colombet, D.; Ayela, F.

2017-04-01

We present a simple process to perform microchannels in which cavitating two phase flows are easily producible. Up to now, hydrodynamic cavitation ‘on a chip’ was reached with small flow rates inside microchannels whose micromachining had involved a deep reactive ion etching (D-RIE). The process we present here does not require a D-RIE reactor, as it is only funded on a wet etching of silicon. It leads to a so-called microstep profile, and large cavitating flow rates become possible together with moderate pressure drops.

A simple process to achieve microchannels geometries able to produce hydrodynamic cavitation

International Nuclear Information System (INIS)

Qiu, X; Cherief, W; Colombet, D; Ayela, F

2017-01-01

We present a simple process to perform microchannels in which cavitating two phase flows are easily producible. Up to now, hydrodynamic cavitation ‘on a chip’ was reached with small flow rates inside microchannels whose micromachining had involved a deep reactive ion etching (D-RIE). The process we present here does not require a D-RIE reactor, as it is only funded on a wet etching of silicon. It leads to a so-called microstep profile, and large cavitating flow rates become possible together with moderate pressure drops. (technical note)

Experimental and numerical investigations on spray structure under the effect of cavitation phenomenon in a microchannel

International Nuclear Information System (INIS)

Ghorbani, Morteza; Sadaghiani, Abdolali Khalili; Yidiz, Mehmet; Kosar, Ali

2017-01-01

In this study, the effect of upstream pressure on cavitation flows inside a microchannel with an inner diameter of 152 μm and resulting spray structure were experimentally and numerically investigated. The effects of bubble number density on two-phase flow hydrodynamics were studied using the numerical approach, where transient model was utilized to obtain the changes in vapor quality inside the microchannel and velocity field near the inlet and outlet of the nozzle. Spray visualization was carried out at a distance of 4.5 mm from the tip of the microchannel using the high speed visualization system. The experimental results showed that the spray cone angle increased with upstream pressure, and beyond the upstream pressure of 50 bar, the liquid jet flow changed to the cloudy spray flow. The bubble collapse was recorded at upstream pressures of 100 and 120 bar, where the cavitation bubbles extended to the outlet of the microchannel, and their collapse took place around the spray

Flow boiling in expanding microchannels

CERN Document Server

Alam, Tamanna

2017-01-01

This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

Metástasis cutánea de carcinoma mamario: cáncer de mama en coraza. Revisión de la literatura y presentación de un caso

Directory of Open Access Journals (Sweden)

Lidia Torres Aja

2012-09-01

Full Text Available En la evolución clínica de los tumores malignos, entre el 1 y el 10,4 % de estos se presentan metástasis cutáneas, por lo que se considera su presencia sinónimo de enfermedad rápidamente progresiva con bajos índices de supervivencia. En los varones, el tumor que más suele producirlas es el de pulmón y en las mujeres, el de mama. Es poco frecuente que la metástasis en la piel sea la primera manifestación del tumor, y es el carcinoma de mama el que con mayor frecuencia da lugar a esta eventualidad. En el caso que se presenta fue la metástasis en la piel la primera manifestación del tumor primario de mama subyacente.

Photon counting with small pore microchannel plates

International Nuclear Information System (INIS)

Martindale, A.; Lapington, J.S.; Fraser, G.W.

2007-01-01

We describe the operation of microchannel plates (MCPs) with 3.2μm diameter channels as photon counting detectors of soft X-rays. Gain and temporal resolution measurements are compared with theoretical scaling laws for channel diameter. A minimum pulse width of 264ps is observed for a two stage multiplier at a total bias voltage of ∼1930V

EXPERIMENTAL PERFORMANCE OF R134a AND R152a USING MICROCHANNEL CONDENSER

OpenAIRE

Bhatkar, V. W.

2018-01-01

An experimental performance study on vapour compression refrigeration system with R134a and drop in substitute R152a with aluminium microchannel condenser was carried out for condensation temperature of 48°C while evaporation temperature varied from -10 to 15°C. Refrigerant charge of R152a was reduced by 40% over R134a with the microchannel condenser. Performance parameters like work input to the compressor, coefficient of performance, refrigerating capacity, condenser capacity and the produc...

Stretchable microelectrode array using room-temperature liquid alloy interconnects

International Nuclear Information System (INIS)

Wei, P; Ziaie, B; Taylor, R; Chung, C; Higgs, G; Pruitt, B L; Ding, Z; Abilez, O J

2011-01-01

In this paper, we present a stretchable microelectrode array for studying cell behavior under mechanical strain. The electrode array consists of gold-plated nail-head pins (250 µm tip diameter) or tungsten micro-wires (25.4 µm in diameter) inserted into a polydimethylsiloxane (PDMS) platform (25.4 × 25.4 mm 2 ). Stretchable interconnects to the outside were provided by fusible indium-alloy-filled microchannels. The alloy is liquid at room temperature, thus providing the necessary stretchability and electrical conductivity. The electrode platform can withstand strains of up to 40% and repeated (100 times) strains of up to 35% did not cause any failure in the electrodes or the PDMS substrate. We confirmed biocompatibility of short-term culture, and using the gold pin device, we demonstrated electric field pacing of adult murine heart cells. Further, using the tungsten microelectrode device, we successfully measured depolarizations of differentiated murine heart cells from embryoid body clusters

Cáncer de mama en varones: casos recogidos en 20 años (1990-2011

Directory of Open Access Journals (Sweden)

Emilio Orquín Ortega

Full Text Available Introducción: en la sociedad occidental el cáncer de mama es el de mayor prevalencia en el sexo femenino, pero es muy raro en el sexo masculino (0,1-0,2 %. Tras analizar la epidemiología y los factores de riesgo, se realizó un estudio retrospectivo de los casos hallados en una unidad de unidad de cirugía menor ambulatoria (CmA del Hospital General de Especialidades Juan Grande en el periodo de 1990 a 2011 (n = 10. Métodos: se describen los hallazgos en la unidad CmA, adonde acuden pacientes con diagnósticos de afecciones benignas, fundamentalmente de piel, anejos cutáneos y tejidos subcutáneos. Se eligió, describió y siguió a los varones que resultaron tener un carcinoma de mama. Los criterios de inclusión fueron el sexo masculino y la confirmación histológica de cáncer de mama. Se estudiaron las variables epidemiológicas, tumorales y terapéuticas, y la supervivencia. Resultados: hubo 10 sujetos con edades de 58 ± 15 años, sin antecedentes de especial interés. Las tumoraciones se localizaban en la cara anterior del tórax, en la región mamaria, de forma unilateral. El 100 % de los pacientes acudieron con diagnóstico de una afección benigna, e igualmente en el 100 % de los casos el diagnóstico anatomopatológico definitivo fue carcinoma ductal. Conclusiones: los pacientes se diagnosticaron después de una cirugía y no hubo diagnóstico clínico previo. La supervivencia estuvo condicionada por la tardanza en el diagnóstico y, por tanto, en el inicio del tratamiento. La supervivencia a los 5 años de revisiones fue de 7 pacientes, aunque algunos fallecieron por otras causas.

Self-separation of blood plasma from whole blood during the capillary flow in microchannel

Science.gov (United States)

Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

2017-11-01

Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. Bharath Babu Nunna is a researcher in mechanical engineering and implementing the novel and innovative technologies in the biomedical devices to enhance the sensitivity of the disease diagnosis.

Magnetic Control of Fe3O4 Nanomaterial for Fat Ablation in Microchannel

Directory of Open Access Journals (Sweden)

Ming Chang

2015-11-01

Full Text Available In this study, surface modification of iron (II, III oxide Fe3O4 nanoparticles by oleic acid (OA coating is investigated for the microablation of fat in a microchannel. The nanoparticles are synthesized by the co-precipitation method and then dispersed in organic solvent prior to mixing with the OA. The magnetization, agglomeration, and particle size distribution properties of the OA-coated Fe3O4 nanoparticles are characterized. The surface modification of the Fe3O4 nanoparticles reveals that upon injection into a microchannel, the lipophilicity of the OA coating influences the movement of the nanoparticles across an oil-phase barrier. The motion of the nanoparticles is controlled using an AC magnetic field to induce magnetic torque and a static gradient field to control linear translation. The fat microablation process in a microchannel is demonstrated using an oscillating driving field of less than 1200 Am−1.

'Zero-time' detectors using microchannel plates for charged particle detection

International Nuclear Information System (INIS)

Girard, J.

1977-01-01

The mass identification of the reaction products detected in heavy ion nuclear reactions is generally obtained by the time-of-flight method. This method requires a device giving first the 'start' signal (zero time at the passage of the particle) and then the stop 'signal'. The interest lying in 'zero-time' detectors using a secondary electron emission has been considerably increased with using microchannel electron multipliers. Nevertheless such a device was shown to induce either fluctuations in the distance of flight or the use of detectors of different type in the 'start' and 'stop' channels respectively. In both cases, it remains an ambiguity as the access to time resolution, in the channel including the electron multiplier, is not direct and the effect of the different parameters on this resolution are masked. To palliate this drawback and study the qualities of microchannel plate multipliers in time measurement field, some devices mechanically and electronically symmetric have been developed. The resolution measurement in time of flight is obtained for electrons generated by the same particle and emitted from either side of a thin film. The distances of flight of the electrons on each side of the film are same, and so are the accelerating potentials. The microchannel electron multipliers and the processing electronic units are the same in each channel [fr

Measuring the local pressure amplitude in microchannel acoustophoresis

DEFF Research Database (Denmark)

Barnkob, Rune; Augustsson, Per; Laurell, Thomas

2010-01-01

/glass microchannels. The system is actuated by a PZT piezo transducer attached beneath the chip and driven by an applied ac voltage near its eigenfrequency of 2 MHz. For a given frequency a number of particle tracks are recorded by a CCD camera and fitted to a theoretical expression for the acoustophoretic motion...

Lattice Boltzmann Simulation of the Hydrodynamic Entrance Region of Rectangular Microchannels in the Slip Regime

Directory of Open Access Journals (Sweden)

Niya Ma

2018-02-01

Full Text Available Developing a three-dimensional laminar flow in the entrance region of rectangular microchannels has been investigated in this paper. When the hydrodynamic development length is the same magnitude as the microchannel length, entrance effects have to be taken into account, especially in relatively short ducts. Simultaneously, there are a variety of non-continuum or rarefaction effects, such as velocity slip and temperature jump. The available data in the literature appearing on this issue is quite limited, the available study is the semi-theoretical approximate model to predict pressure drop of developing slip flow in rectangular microchannels with different aspect ratios. In this paper, we apply the lattice Boltzmann equation method (LBE to investigate the developing slip flow through a rectangular microchannel. The effects of the Reynolds number (1 < Re < 1000, channel aspect ratio (0 < ε < 1, and Knudsen number (0.001 < Kn < 0.1 on the dimensionless hydrodynamic entrance length, and the apparent friction factor, and Reynolds number product, are examined in detail. The numerical solution of LBM can recover excellent agreement with the available data in the literature, which proves its accuracy in capturing fundamental fluid characteristics in the slip-flow regime.

Numerical study on fabricating rectangle microchannel in microfluidic chips by glass molding process

Science.gov (United States)

Wang, Tao; Chen, Jing; Zhou, Tianfeng

2017-09-01

This paper studied the glass molding process (GMP) for fabricating a typical microstructure of glass microfluidic chips, i. e., rectangle microchannel, on soda-lime glass by finite element method. More than 100 models were established on the platform of Abaqus/Standard. The influence of parameters, i. e., temperature, aspect ratio, side wall angle and friction coefficient on deformation were studied, and the predicted morphology of the molded microchannel were presented as well. The research could provide fundamental experience for optimizing GMP process in the future.

Cáncer en mama supernumeraria. Presentación de un caso. Hospital Clínico Quirúrgico Docente 10 de Octubre

Directory of Open Access Journals (Sweden)

Alfonso Guillermo Ramos Sosa

2017-01-01

Full Text Available La presencia de tejido mamario ectópico o mama supernumeraria, desarrollado a lo largo de la línea mamaria, es infrecuente, pero tiene un alto riesgo de malignizarse. Se presenta el caso de una paciente de 71 años de edad, que presentó una masa aumentada de volumen en el extremo superior de la línea mamaria, cercana a la axila derecha, y otra masa ubicada a la hora 12 del reloj, cercano a la areola. El estudio anatomopatológico de ambos procesos tumorales de la mama derecha correspondió con un carcinoma lobular. La paciente fue intervenida quirúrgicamente, encontrándose una adenopatía axilar derecha positiva de enfermedad maligna. Recibió tratamiento adyuvante con quimioterapia, radioterapia y hormonoterapia.

Photochemical immobilization of protein on the inner wall of a microchannel and Its application in a glucose sensor

International Nuclear Information System (INIS)

Nakajima, Hizuru; Ishino, Satomi; Masuda, Hironori; Nakagama, Tatsuro; Shimosaka, Takuya; Uchiyama, Katsumi

2006-01-01

A new protein immobilization technique has been developed for patterning enzymes in a specific position inside a microchannel. First, bovine serum albumin (BSA) was adsorbed onto the internal surface of a polydimethylsiloxane microchannel. The microchannel was then filled with the conjugate solution of a photoreactive cross-linker, 4-azido-2,3,5,6-tetrafluorobenzoic acid succinimidyl ester (ATFB-SE), and an enzyme, horseradish peroxidase (HRP). An irradiation by a He-Cd laser activated the azido group of the conjugates and these conjugates became covalently attached to the adsorbed BSA on the microchannel. The enzyme turnover was observed from only the HRP zone. This technique was successfully applied to the enzymatic glucose sensor. Glucose oxidase (GOD) and HRP were sequentially patterned in a single microchannel, i.e., the HRP zone was located downstream from the GOD zone. The calibration curve of a glucose standard solution was linear over the range of 0-128 μM with a correlation coefficient of 0.993. Compared to the traditional method using a 96-well microtiter plate, the present technique on the microchip shortened the reaction time from 30 min to 4.8 s, i.e., to 1/375

Gradiently Polymerized Solid Electrolyte Meets with Micro/Nano-Structured Cathode Array.

Science.gov (United States)

Dong, Wei; Zeng, Xian-Xiang; Zhang, Xu-Dong; Li, Jin-Yi; Shi, Ji-Lei; Xiao, Yao; Shi, Yang; Wen, Rui; Yin, Ya-Xia; Wang, Tai-Shan; Wang, Chun-Ru; Guo, Yu-Guo

2018-05-02

The poor contact between the solid-state electrolyte and cathode materials leads to high interfacial resistance, severely limiting the rate capability of solid Li metal batteries. Herein, an integrative battery design is introduced with a gradiently polymerized solid electrolyte (GPSE), a micro-channel current collector array and nano-sized cathode particles. In-situ formed GPSE encapsulates cathode nanoparticles in the micro-channel with ductile inclusions to lower interfacial impedance, and the stiff surface layer of GPSE toward anode suppresses Li dendrites growth. Li metal batteries based on GPSE and Li-free hydrogenated V2O5 (V2O5-H) cathode exhibit an outstanding high-rate response of up to 5 C (the capacity ratio of 5 C / 1 C is 90.3%) and an ultralow capacity fade rate of 0.07% per cycle over 300 cycles. Other Li-containing cathodes as LiFePO4 and LiNi0.5Mn0.3Co0.2O2 can also operate effectively at 5 C and 2 C rate, respectively. Such an ingenious design may provide new insights into other solid metal batteries through interfacial engineering manipulation at micro and nano level.

Valor pronóstico del análisis de marcadores moleculares mediante proteómica dirigida en cáncer de mama precoz con receptores hormonales positivos

OpenAIRE

Martinez del Prado, María Purificación

2018-01-01

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Medicina. Fecha de lectura: 22-03-2018 Introducción: El cáncer de mama (CM) es una enfermedad heterogénea a nivel molecular. La proteómica dirigida permite la investigación de potenciales biomarcadores, factores pronósticos, predictivos, diagnósticos y nuevas dianas terapéuticas en el cáncer de mama. En una serie inicial de pacientes (cohorte de descubrimiento) con CM, receptores hormon...

An adhesive bonding method with microfabricating micro pillars to prevent clogging in a microchannel

International Nuclear Information System (INIS)

Chen, Pin-Chuan; Liu, Yu-Min; Chou, Huang-Chieh

2016-01-01

Thermoplastics are widely used in the fabrication of microfluidic chips, due to their low cost, flexibility in manufacturing, and applicability in large-scale production. This paper presents a novel bonding method for the assembly of thermoplastic microfluidic chips, with the aim of preventing the flow of UV adhesive into microchannels during the bonding process. The proposed bonding methodology depends primarily on controlling the thickness of the UV adhesive, which is achieved by using spin-coating for the uniform UV adhesive in conjunction with the microfabrication of short pillars for keeping a uniform gap between the two bonded surfaces. In this study, two devices with serpentine microchannels (cross-sectional area of 500 μm  ×  500 μm and 200 μm  ×  200 μm) were fabricated on PMMA substrates using a micromilling machine, whereupon a hydrophobic coating was applied to the walls of 200 μm  ×  200 μm microchannels in order to prevent clogging, which might otherwise be caused by the seepage of UV adhesive into the channels. A variety of experiments were used to characterize the quality of bonding, the results of which reveal the following: (1) no leakage was observed in either of the microfluidic chips; (2) the hydrophobic coating proved highly effective in preventing the flow of UV adhesive into the smaller microchannels; (3) the average amount of clogging inside 500 μm  ×  500 μm microchannels was 1.13% with standard deviation of 0.55%, while the average amount of clogging inside 200 μm  ×  200 μm microchannels was 1.65% with standard deviation of 0.92%; (4) the average thickness of the UV adhesive in a 500 μm  ×  500 μm microfluidic chip was 32 μm with standard deviation of 2 μm, whereas the average thickness of the UV adhesive in a 200 μm  ×  200 μm microfluidic chip was 31 μm with standard deviation of 1.2 μm; (5) the two chips possess sufficient bonding strength to withstand

Entropy generation minimization of a MHD (magnetohydrodynamic) flow in a microchannel

Energy Technology Data Exchange (ETDEWEB)

Ibanez, Guillermo [Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutierrez, Chiapas 29000 (Mexico); Cuevas, Sergio [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico A.P. 34, Temixco, Mor. 62580 (Mexico)

2010-10-15

The dissipative processes that arise in a microchannel flow subjected to electromagnetic interactions, as occurs in a MHD (magnetohydrodynamic) micropump, are analyzed. The entropy generation rate is used as a tool for the assessment of the intrinsic irreversibilities present in the microchannel owing to viscous friction, heat flow and electric conduction. The flow in a parallel plate microchannel produced by a Lorentz force created by a transverse magnetic field and an injected electric current is considered assuming a thermally fully developed flow and conducting walls of finite thickness. The conjugate heat transfer problem in the fluid and solid walls is solved analytically using thermal boundary conditions of the third kind at the outer surfaces of the walls and continuity of temperature and heat flux across the fluid-wall interfaces. Velocity, temperature and current density fields in the fluid and walls are used to calculate the global entropy generation rate. Conditions under which this quantity is minimized are determined for specific values of the geometrical and physical parameters of the system. The Nusselt number is also calculated and explored for different conditions. Results can be used to determine optimized conditions that lead to a minimum dissipation consistent with the physical constraints demanded by the microdevice. (author)

Lipídio: fator de risco e prevenção do câncer de mama Lipid: risk factor and breast cancer prevention

Directory of Open Access Journals (Sweden)

Gabriela Herrmann Cibeira

2006-02-01

Full Text Available A hipótese de que uma dieta rica em gordura promova o desenvolvimento do câncer de mama na menopausa é fortalecida por estudos caso-controle, que mostram forte associação positiva entre uma dieta rica em lipídios e as taxas de incidência de câncer de mama. Por outro lado, a ingestão dietética de gordura não parece estar relacionada com o risco de câncer de mama em estudos de coorte. Em vista desses achados conflitantes, tem sido difícil propor qualquer recomendação nutricional para a prevenção do câncer de mama. Estudos com animais e observações recentes em humanos, entretanto, têm mostrado evidências de que a dieta rica em ácido graxo linoléico estimula vários estágios no desenvolvimento de câncer mamário. Alguns estudos ainda mostram que o óleo de peixe, constituído de ácidos graxos ômega-3, parece prevenir o câncer pela influência sobre a atividade de enzimas e proteínas relacionadas à proliferação celular. Assim, são necessários estudos epidemiológicos que integrem as interações de ácidos graxos específicos com o catabolismo hormonal, fatores nutricionais protetores e de risco relacionados com o câncer de mama. Nesse trabalho, abordaremos os fatores protetores, de risco e as implicações quali e quantitativas dos ácidos graxos da dieta sobre o câncer de mama.The hypothesis that a high fat diet promotes the development of postmenopausal breast cancer is supported by case-controls studies that show a strong correlation between fat intake and breast cancer rates. On the other hand, high fat intake is not correlated with breast cancer in cohort studies. In view of these conflicting findings, it has been difficult to propose nutritional recommendations for the prevention of breast cancer. Animal studies and recent observations in humans have shown that a diet high in polyunsaturated fatty acids stimulates several stages in the development of mammary cancer. Some evidences show that fish oil

Entropy generation and optimization of laminar convective heat transfer and fluid flow in a microchannel with staggered arrays of pin fin structure with tip clearance

International Nuclear Information System (INIS)

Shi, Zhongyuan; Dong, Tao

2015-01-01

Highlights: • Entropy generation from heat transfer and flow friction are investigated synthetically. • The impact of correlated variables, dimensionless tip clearance, aspect ratio and Reynolds number, are discussed. • Physical interpretation of the result from multiobjective entropy generation minimization is presented. - Abstract: Entropy generation rate accounting for heat transfer and flow friction is presented for the flow in microchannel with staggered pin fin arrays, clearance existing between the pin fin tip and the shroud plate. Within the scope of the present work, entropy generation rate due to heat transfer is levels of magnitude higher than that from flow friction, which is nonetheless not negligible considering its scaling effect on the pumping power consumption, for all cases under investigation. For the pin fin structure with high aspect ratio (height-to-diameter), the effect of tip clearance was found more pronounced with a conductive nature competing with the convective. When this ratio is low, the convective effect dominates the variation of entropy generation by heat transfer and flow friction, the effect of the clearance gap favored by higher aspect ratio. The entropy minimization method is applied to seek for an optimal combination of all impact factors under investigation. The Pareto frontier along with its corresponding solution sets are obtained by Multiobjective Optimization Genetic Algorithm. The solution sets acquired for the scenario with high-aspect-ratio pin fin fall within the region of lower pin fin density where the trade off between the convective and the conductive effects is identified. On the other hand, dominated by the convective nature, the solution sets for cases with lower aspect ratio are in principle located at the upper bounds

Hydrophilic Surface Modification of PDMS Microchannel for O/W and W/O/W Emulsions

Directory of Open Access Journals (Sweden)

Shazia Bashir

2015-09-01

Full Text Available A surface modification method for bonded polydimethylsiloxane (PDMS microchannels is presented herein. Polymerization of acrylic acid was performed on the surface of a microchannel using an inline atmospheric pressure dielectric barrier microplasma technique. The surface treatment changes the wettability of the microchannel from hydrophobic to hydrophilic. This is a challenging task due to the fast hydrophobic recovery of the PDMS surface after modification. This modification allows the formation of highly monodisperse oil-in-water (O/W droplets. The generation of water-in-oil-in-water (W/O/W double emulsions was successfully achieved by connecting in series a hydrophobic microchip with a modified hydrophilic microchip. An original channel blocking technique to pattern the surface wettability of a specific section of a microchip using a viscous liquid comprising a mixture of honey and glycerol, is also presented for generating W/O/W emulsions on a single chip.

Two-phase pressure drop and flow visualization of FC-72 in a silicon microchannel heat sink

International Nuclear Information System (INIS)

Megahed, Ayman; Hassan, Ibrahim

2009-01-01

The rapid development of two-phase microfluidic devices has triggered the demand for a detailed understanding of the flow characteristics inside microchannel heat sinks to advance the cooling process of micro-electronics. The present study focuses on the experimental investigation of pressure drop characteristics and flow visualization of a two-phase flow in a silicon microchannel heat sink. The microchannel heat sink consists of a rectangular silicon chip in which 45 rectangular microchannels were chemically etched with a depth of 276 μm, width of 225 μm, and a length of 16 mm. Experiments are carried out for mass fluxes ranging from 341 to 531 kg/m 2 s and heat fluxes from 60.4 to 130.6 kW/m 2 using FC-72 as the working fluid. Bubble growth and flow regimes are observed using high speed visualization. Three major flow regimes are identified: bubbly, slug, and annular. The frictional two-phase pressure drop increases with exit quality for a constant mass flux. An assessment of various pressure drop correlations reported in the literature is conducted for validation. A new general correlation is developed to predict the two-phase pressure drop in microchannel heat sinks for five different refrigerants. The experimental pressure drops for laminar-liquid laminar-vapor and laminar-liquid turbulent-vapor flow conditions are predicted by the new correlation with mean absolute errors of 10.4% and 14.5%, respectively.

RTOG criteria to evaluate acute skin reaction and its risk factors in patients with breast cancer submitted to radiotherapy Evaluación de las reacciones agudas de la piel y sus factores de riesgo en pacientes con cáncer de mama sometidos a radioterapia Avaliação das reações agudas da pele e seus fatores de risco em pacientes com câncer de mama submetidas à radioterapia

Directory of Open Access Journals (Sweden)

Ana Maria Teixeira Pires

2008-10-01

Full Text Available PURPOSE: Evaluate and classify skin reactions through the Radiation Therapy Oncology Group (RTOG criteria and characterize factors that can intervene in these reactions. METHOD: Prospective study, with 86 women submitted to adjuvant breast radiotherapy with a total dose of 5040cGy, in a 6 MeV Linear Accelerator. Personal data were collected and breast size was measured (distance between field separation and breast height. The treated skin area was evaluated weekly. RESULTS: Breast height and treatment technique were significant factors in the univariate analysis for the incidence of degree 3 skin reactions. However, only breast height was a significant factor in the multivariate analysis for the severity of skin reactions. The chances of occurring degree 3 reactions increase 2.61 times for each increase in height unit (cm. These findings allow nurses to plan more adequate and individualized procedures for each patient and contribute to the optimization of treatment.El objetivo fue evaluar y clasificar las reacciones de la piel según los criterios del Radiation Therapy Oncology Group (RTOG y caracterizar factores que puedan interferir en esas reacciones. METODOLOGÍA: Estudio prospectivo, con 86 mujeres sometidas a la radioterapia en la mama, dosis total de 5040cGy, con Acelerador Lineal de 6 MeV. Fueron recolectados datos personales y medido el tamaño de la mama (distancia entre la separación de los campos y la altura de la mama. La evaluación de la piel del área de tratamiento fue realizada semanalmente. RESULTADOS: La altura de la mama y la técnica de tratamiento fueron significativos en el análisis univariado, para incidencia de reacción de piel grado 3. Sin embargo, solamente la altura de la mama fue el factor significativo en el análisis multivariado para la gravedad de la reacción de la piel. La probabilidad de ocurrir una reacción grado 3 aumenta 2,61 veces por cada aumento de 1 unidad de altura en cm. Lo encontrado le permite

Estratégias de instituições da sociedade civil no acesso a medicamentos para câncer de mama no SUS

Directory of Open Access Journals (Sweden)

Aline Scaramussa Deprá

2015-07-01

Full Text Available Esta pesquisa objetiva identificar e analisar as estratégias de instituições da sociedade civil dedicadas ao câncer de mama (ISC-CM no acesso a medicamentos no SUS e seus principais atores sociais. Utilizou-se a abordagem qualitativa, empregando-se os métodos de análise de redes sociais e bola-de-neve e as técnicas de observação participante e entrevistas semiestruturadas. A análise temática baseou-se nas categorias: acesso a medicamentos para tratamento de câncer de mama; relacionamento das ISC-CM com o Estado; relacionamento das ISC-CM com a indústria farmacêutica; e outras estratégias utilizadas por ISC-CM no acesso a medicamentos. Os resultados mostraram que as ISC-CM têm influenciado o acesso a medicamentos para câncer de mama no SUS e sua principal estratégia é a pressão sobre o Estado. A indústria farmacêutica patrocina algumas dessas instituições para fortalecê-las com o intuito de ampliar seu mercado. As principais dificuldades no acesso a medicamentos se referem à deficiência de serviços, à iniquidade dos tratamentos oferecidos, e à inclusão de tecnologias no SUS.

Effect of junction configurations on microdroplet formation in a T-junction microchannel

Science.gov (United States)

Lih, F. L.; Miao, J. M.

2015-03-01

This study investigates the dynamic formation process of water microdroplets in a silicon oil flow in a T-junction microchannel. Segmented water microdroplets are formed at the junction when the water flow is perpendicularly injected into the silicon oil flow in a straight rectangular microchannel. This study further presents the effects of the water flow inlet geometry on hydrodynamic characteristics of water microdroplet formation. A numerical multiphase volume of fluid (VOF) scheme is coupled to solve the unsteady three-dimensional laminar Navier-Stokes equations to depict the droplet formation phenomena at the junction. Predicted results on the length and generated frequency of the microdroplets agree well with experimental results in a T-junction microchannel with straight and flat inlets (the base model) for both fluid flows. Empirical correlations are reported between the volumetric flow ratio and the dimensionless microdroplet length or dimensionless frequency of droplet generation at a fixed capillary number of 4.7 · 10-3. The results of this study indicate a reduction in the droplet length of approximately 21% if the straight inlet for the water flow is modified to a downstream sudden contraction inlet for the water flow.

Prevention of Postpartum Depression in Low-Income Women: Development of the "Mamas y Bebes"/Mothers and Babies Course

Science.gov (United States)

Munoz, Ricardo F.; Le, Huynh-Nhu; Ippen, Chandra Ghosh; Diaz, Manuela A.; Urizar, Guido G., Jr.; Soto, Jose; Mendelson, Tamar; Delucchi, Kevin; Lieberman, Alicia F.

2007-01-01

A prenatal intervention designed to prevent the onset of major depressive episodes (MDEs) during pregnancy and postpartum was pilot tested at a public sector women's clinic. The "Mamas y Bebes"/Mothers and Babies Course is an intervention developed in Spanish and English that uses a cognitive-behavioral mood management framework, and incorporates…

The measurements of water flow rates in the straight microchannel based on the scanning micro-PIV technique

Science.gov (United States)

Wang, H. L.; Han, W.; Xu, M.

2011-12-01

Measurement of the water flow rate in microchannel has been one of the hottest points in the applications of microfluidics, medical, biological, chemical analyses and so on. In this study, the scanning microscale particle image velocimetry (scanning micro-PIV) technique is used for the measurements of water flow rates in a straight microchannel of 200μm width and 60μm depth under the standard flow rates ranging from 2.481μL/min to 8.269μL/min. The main effort of this measurement technique is to obtain three-dimensional velocity distribution on the cross sections of microchannel by measuring velocities of the different fluid layers along the out-of-plane direction in the microchannel, so the water flow rates can be evaluated from the discrete surface integral of velocities on the cross section. At the same time, the three-dimensional velocity fields in the measured microchannel are simulated numerically using the FLUENT software in order to verify the velocity accuracy of measurement results. The results show that the experimental values of flow rates are well consistent to the standard flow rates input by the syringe pump and the compared results between numerical simulation and experiment are consistent fundamentally. This study indicates that the micro-flow rate evaluated from three-dimensional velocity by the scanning micro-PIV technique is a promising method for the micro-flow rate research.

All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmitters

Science.gov (United States)

Picollo, Federico; Battiato, Alfio; Bernardi, Ettore; Plaitano, Marilena; Franchino, Claudio; Gosso, Sara; Pasquarelli, Alberto; Carbone, Emilio; Olivero, Paolo; Carabelli, Valentina

2016-02-01

We report on the ion beam fabrication of all-carbon multi electrode arrays (MEAs) based on 16 graphitic micro-channels embedded in single-crystal diamond (SCD) substrates. The fabricated SCD-MEAs are systematically employed for the in vitro simultaneous amperometric detection of the secretory activity from populations of chromaffin cells, demonstrating a new sensing approach with respect to standard techniques. The biochemical stability and biocompatibility of the SCD-based device combined with the parallel recording of multi-electrodes array allow: i) a significant time saving in data collection during drug screening and/or pharmacological tests over a large number of cells, ii) the possibility of comparing altered cell functionality among cell populations, and iii) the repeatition of acquisition runs over many cycles with a fully non-toxic and chemically robust bio-sensitive substrate.

Entropy generation of nanofluid flow in a microchannel heat sink

Science.gov (United States)

Manay, Eyuphan; Akyürek, Eda Feyza; Sahin, Bayram

2018-06-01

Present study aims to investigate the effects of the presence of nano sized TiO2 particles in the base fluid on entropy generation rate in a microchannel heat sink. Pure water was chosen as base fluid, and TiO2 particles were suspended into the pure water in five different particle volume fractions of 0.25%, 0.5%, 1.0%, 1.5% and 2.0%. Under laminar, steady state flow and constant heat flux boundary conditions, thermal, frictional, total entropy generation rates and entropy generation number ratios of nanofluids were experimentally analyzed in microchannel flow for different channel heights of 200 μm, 300 μm, 400 μm and 500 μm. It was observed that frictional and total entropy generation rates increased as thermal entropy generation rate were decreasing with an increase in particle volume fraction. In microchannel flows, thermal entropy generation could be neglected due to its too low rate smaller than 1.10e-07 in total entropy generation. Higher channel heights caused higher thermal entropy generation rates, and increasing channel height yielded an increase from 30% to 52% in thermal entropy generation. When channel height decreased, an increase of 66%-98% in frictional entropy generation was obtained. Adding TiO2 nanoparticles into the base fluid caused thermal entropy generation to decrease about 1.8%-32.4%, frictional entropy generation to increase about 3.3%-21.6%.

Experimental study on frosting control of mobile air conditioning system with microchannel evaporator

International Nuclear Information System (INIS)

Qu Xiaohua; Shi Junye; Qi Zhaogang; Chen Jiangping

2011-01-01

In this paper, a newly developed frost control system is proposed. System bench tests and vehicle test in wind tunnel have been carried out to explore the anti-frosting performance of automotive air conditioning system with microchannel evaporator. The experimental results are compared with the baseline conventional laminated evaporator system. The test results show that the installation position of temperature sensor can dramatically affect the anti-frosting performance. The clutch switching on/off temperature range of the microchannel evaporator is also experimentally studied. The test results show that, with a proper installation position and on/off temperature range, the system COP can be improved, and meanwhile the panel vents' air off temperature can be reduced, and temperature swing can be reduced. - Highlights: → The frost control systems were tested with microchannel and laminated evaporators separately. → The installation position of temperature sensor affects the anti-frosting performance. → Temperature control range affects the anti-frosting performance. → The panel vents' air off temperature and swing can be reduced by proper control parameters. → The system COP can be improved by proper control parameters.

Effect of patterned micro-magnets on superparamagnetic beads in microchannels

International Nuclear Information System (INIS)

Guo, S S; Deng, Y L; Zhao, L B; Zhao, X-Z; Chan, H L W

2008-01-01

The trapping response of patterned micro-magnets (PMMs) was studied based on the parameters affecting superparamagnetic beads in microfluidic channels. Using replica moulding and electroplating technologies, the PMMs were fabricated on the microchannel bottom, which generated sufficient magnetic forces to bias the moments of magnetic particles in a flowing stream. A simplified physical principle was used to analyse the relative velocity of the magnetic particle in the confined space of a microchannel. The results revealed that the magnetic force contributed to the fluidic flow rate as well as to the hydrodynamic drag force. The relative velocity of magnetic particles was dependent on the frequency under an external magnetic field driven by an alternate current (ac) source. It showed that the magnetic gradient induced hysteresis characteristics of the transmission spectrum, associated with the interaction of superparamagnetic beads and magnetic field

The flow field around a micropillar confined in a microchannel

International Nuclear Information System (INIS)

Jung, Junkyu; Kuo, C.-J.; Peles, Yoav; Amitay, Michael

2012-01-01

The flow field over a low aspect ratio (AR) circular pillar (L/D = 1.5) in a microchannel was studied experimentally. Microparticle image velocimetry (μPIV) was employed to quantify flow parameters such as flow field, spanwise vorticity, and turbulent kinetic energy (TKE) in the microchannel. Flow regimes of cylinder-diameter-based Reynolds number at 100 ⩽ Re D ⩽ 700 (i.e., steady, transition from quasi-steady to unsteady, and unsteady flow) were elucidated at the microscale. In addition, active flow control (AFC), via a steady control jet (issued from the pillar itself in the downstream direction), was implemented to induce favorable disturbances to the flow in order to alter the flow field, promote turbulence, and increase mixing. Together with passive flow control (i.e., a circular pillar), turbulent kinetic energy was significantly increased in a controllable manner throughout the flow field.

Social support and cervical and breast cancer screening practices among nurses Apoyo social y rastreo de cáncer uterino y de mama entre las trabajadoras de enfermería Apoio social e rastreamento de câncer uterino e de mama entre trabalhadoras de enfermagem

Directory of Open Access Journals (Sweden)

Isis Teixeira e Silva

2009-08-01

Full Text Available This cross-sectional epidemiological study was carried out at three public hospitals in Rio de Janeiro, RJ, Brazil. It aimed at analyzing the association between social support and cervical and breast cancer early detection practices among nurses. Data were collected through a multidimensional questionnaire focusing on socio-demographic and occupational variables, the performance of the breast self-exam, the Papanicolaou smear test, and social support (Medical Outcomes Study scale. Statistical associations were evaluated through the Chi-square test (p d" 0.05. Logistic regression tests were used for multivariate analysis. Higher levels of social support consistently increased the chances of individuals reporting adequate practices concerning breast self-examination and having Pap smear tests performed, regardless of socio-demographic or occupational variables. These results corroborate the hypotheses that social support has a positive effect on the regular practice of self-care.Estudio epidemiológico, seccional, realizado en tres hospitales públicos de Río de Janeiro, en Brasil, con el objetivo de analizar la asociación entre el apoyo social y las prácticas de detección precoz de cáncer uterino y de mama entre trabajadoras de enfermería. Los datos fueron recolectados a través de un cuestionario multidimensional referente a variables socio demográficas y ocupacionales, a la realización del Papanicolaou, al auto examen de las mamas y al apoyo social (escala Medical Outcomes Studiy. Las asociaciones estadísticas fueron evaluadas a través de la prueba chi-cuadrado con niveles de significancia de 5%. Se utilizó la regresión logística para el análisis multivariado. De manera consistente, mayores niveles de apoyo social aumentaron las chances de la realización de prácticas adecuadas, del examen Papanicolaou y del auto examen de las mamas, después de ajuste por variables socios demográficos y ocupacionales. Esos resultados

Feasibility investigations on a novel micro-manufacturing process for fabrication of fuel cell bipolar plates: Internal pressure-assisted embossing of micro-channels with in-die mechanical bonding

Energy Technology Data Exchange (ETDEWEB)

Koc, Muammer [NSF I/UCR Center for Precision Forming (CPF), Department of Mechanical Engineering, Virginia Commonwealth University (VCU), Richmond, VA (United States); Mahabunphachai, Sasawat [NSF I/UCR Center for Precision Forming (CPF), Department of Mechanical Engineering, Virginia Commonwealth University (VCU), Richmond, VA (United States); Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States)

2007-10-25

In this paper, we present the results of our studies on conceptual design and feasibility experiments towards development of a novel hybrid manufacturing process to fabricate fuel cell bipolar plates that consists of multi-array micro-channels on a large surface area. The premises of this hybrid micro-manufacturing process stem from the use of an internal pressure-assisted embossing process (cold or warm) combined with mechanical bonding of double bipolar plates in a single-die and single-step operation. Such combined use of hydraulic and mechanical forming forces and in-process bonding will (a) enable integrated forming of micro-channels on both surfaces (as anode and cathode flow fields) and at the middle (as cooling channels), (b) reduce the process steps, (c) reduce variation in dimensional tolerances and surface finish, (d) increase the product quality, (e) increase the performance of fuel cell by optimizing flow-field designs and ensuring consistent contact resistance, and (f) reduce the overall stack cost. This paper explains two experimental investigations that were performed to characterize and evaluate the feasibility of the conceptualized manufacturing process. The first investigation involved hydroforming of micro-channels using thin sheet metals of SS304 with a thickness of 51 {mu}m. The width of the channels ranged from 0.46 to 1.33 mm and the height range was between 0.15 and 0.98 mm. Our feasibility experiments resulted in that different aspect ratios of micro-channels could be fabricated using internal pressure in a controllable manner although there is a limit to very sharp channel shapes (i.e., high aspect ratios with narrow channels). The second investigation was on the feasibility of mechanical bonding of thin sheet metal blanks. The effects of different process and material variables on the bond quality were studied. Successful bonding of various metal blanks (Ni201, Al3003, and SS304) was obtained. The experimental results from both

Batch production of microchannel plate photo-multipliers

Energy Technology Data Exchange (ETDEWEB)

Frisch, Henry J.; Wetstein, Matthew; Elagin, Andrey

2018-03-06

In-situ methods for the batch fabrication of flat-panel micro-channel plate (MCP) photomultiplier tube (PMT) detectors (MCP-PMTs), without transporting either the window or the detector assembly inside a vacuum vessel are provided. The method allows for the synthesis of a reflection-mode photocathode on the entrance to the pores of a first MCP or the synthesis of a transmission-mode photocathode on the vacuum side of a photodetector entrance window.

Convective boiling in a parallel microchannel heat sink with a diverging cross-section design and artificial nucleation sites

International Nuclear Information System (INIS)

Lu, Chun Ting; Pan, Chin

2009-01-01

To develop a highly stable boiling heat transfer microchannel heat sink, the three types of diverging microchannels, namely Type-1, Type-2 and Type-3, were designed to explore experimentally the effect of different distribution of artificial nucleation sites on enhancing boiling heat transfer in 10 parallel diverging microchannels with a mean hydraulic diameter of 120 μm. The Type-1 system is with no cavities, Type-2 is with cavities distributed uniformly along the downstream half of the channel, while Type-3 is with cavities distributed uniformly along the whole channel. The artificial nucleation sites are laser-etched pits on the channel bottom wall with a mouth diameter of about 20-22 μm based on the heterogeneous nucleation theory. The results of the present study reveal the presence of the artificial nucleation sites for flow boiling in parallel diverging microchannel significantly reduces the wall superheat and enhances the boiling heat transfer performance. Additionally, the Type-3 design demonstrates the best boiling heat transfer performance. (author)

Caracterização do perfil clínico, laboratorial, citológico e histopatológico em cadelas portadoras de tumor da mama submetidas à mastectomia.

OpenAIRE

Michelle Suassuna de Azevedo Rêgo

2011-01-01

Com o aumento da expectativa de vida dos cães, os tumores da mama tem se tornado uma patologia cada vez mais frequente na Medicina Veterinária e se faz necessário uma abordagem clínica precoce para que a terapêutica seja eficaz e proporcione melhor qualidade de vida e prolongamento do tempo de sobrevida. Diante da alta incidência, esta pesquisa teve como objetivo caracterizar clínica, laboratorial, citológica e histopatologicamente os tumores da mama de cadelas sem predileção de raça, idade, ...

Diamond Microchannel Heat Sink Designs For High Heat Flux Thermal Control

National Research Council Canada - National Science Library

Corbin, Michael

2002-01-01

.... Many investigators have suggested the use of diamond heat spreaders to reduce flux levels at or near to its source, and some have suggested that diamond microchannel heat sinks ultimately may play...

Evaluation of Superficial and Dimensional Quality Features in Metallic Micro-Channels Manufactured by Micro-End-Milling

Directory of Open Access Journals (Sweden)

Claudio Giardini

2013-04-01

Full Text Available Miniaturization encourages the development of new manufacturing processes capable of fabricating features, like micro-channels, in order to use them for different applications, such as in fuel cells, heat exchangers, microfluidic devices and micro-electromechanical systems (MEMS. Many studies have been conducted on heat and fluid transfer in micro-channels, and they appeared significantly deviated from conventional theory, due to measurement errors and fabrication methods. The present research, in order to deal with this opportunity, is focused on a set of experiments in the micro-milling of channels made of aluminum, titanium alloys and stainless steel, varying parameters, such as spindle speed, depth of cut per pass (ap, channel depth (d, feed per tooth (fz and coolant application. The experimental results were analyzed in terms of dimensional error, channel profile shape deviation from rectangular and surface quality (burr and roughness. The micro-milling process was capable of offering quality features required on the micro-channeled devices. Critical phenomena, like run-out, ploughing, minimum chip thickness and tool wear, were encountered as an explanation for the deviations in shape and for the surface quality of the micro-channels. The application of coolant and a low depth of cut per pass were significant to obtain better superficial quality features and a smaller dimensional error. In conclusion, the integration of superficial and geometrical features on the study of the quality of micro-channeled devices made of different metallic materials contributes to the understanding of the impact of calibrated cutting conditions in MEMS applications.

Cavitation in flow through a micro-orifice inside a silicon microchannel

Science.gov (United States)

Mishra, Chandan; Peles, Yoav

2005-01-01

Hydrodynamic cavitation in flows through a micro-orifice entrenched in a microchannel has been detected and experimentally investigated. Microfabrication techniques have been employed to design and develop a microfluidic device containing an 11.5μm wide micro-orifice inside a 100.2μm wide and 101.3μm deep microchannel. The flow of de-ionized water through the micro-orifice reveals the presence of multifarious cavitating flow regimes. This investigation divulges both similarities and differences between cavitation in micro-orifices and cavitation in their macroscale counterparts. The low incipient cavitation number obtained from the current experiments suggests a dominant size scale effect. Choking cavitation is observed to be independent of any pressure or velocity scale effects. However, choking is significantly influenced by the small stream nuclei residence time at such scales. Flow rate choking leads to the establishment of a stationary cavity. Large flow and cavitation hysteresis have been detected at the microscale leading to very high desinent cavitation numbers. The rapid transition from incipient bubbles to choking cavitation and subsequent supercavitation suggests the presence of radically different flow patterns at the microscale. Supercavitation results in a thick cavity, which extends throughout the microchannel, and is encompassed by the liquid. Cavitation at the microscale is expected to considerably influence the design of innovative high-speed microfluidic systems.

Electrohydrodynamic actuation of co-flowing liquids by means of microelectrode arrays

International Nuclear Information System (INIS)

Garcia-Sanchez, Pablo; Ferney, Mathieu; Ramos, Antonio

2011-01-01

Electric fields induce forces at the interface between liquids with different electrical properties (conductivity and/or permittivity). We explore how to use these forces for manipulating two coflowing streams of liquids in a microchannel. A microelectrode array is fabricated at the bottom of the channel and one of the two liquids is labelled with a fluorescent dye for observing the phenomenon. The diffuse interface between the two liquids is deflected depending on the ac signal and conductivity (or permittivity) ratio between the liquids. Only a few volts are needed for observing the interface destabilization, in contrast with other electrode configurations where hundreds of volts are applied.

Electrohydrodynamic actuation of co-flowing liquids by means of microelectrode arrays

Energy Technology Data Exchange (ETDEWEB)

Garcia-Sanchez, Pablo; Ferney, Mathieu; Ramos, Antonio, E-mail: pablogarcia@us.es [Depto. de Electronica y Electromagnetismo, University of Sevilla (Spain)

2011-06-23

Electric fields induce forces at the interface between liquids with different electrical properties (conductivity and/or permittivity). We explore how to use these forces for manipulating two coflowing streams of liquids in a microchannel. A microelectrode array is fabricated at the bottom of the channel and one of the two liquids is labelled with a fluorescent dye for observing the phenomenon. The diffuse interface between the two liquids is deflected depending on the ac signal and conductivity (or permittivity) ratio between the liquids. Only a few volts are needed for observing the interface destabilization, in contrast with other electrode configurations where hundreds of volts are applied.

Bone mineral density in postmenopausal women with and without breast cancer Densidade mineral óssea em mulheres na pós-menopausa com e sem câncer de mama

Directory of Open Access Journals (Sweden)

Délio Marques Conde

2012-12-01

Full Text Available OBJECTIVE: The values of bone mineral density (BMD were compared in postmenopausal women with and without breast cancer. METHODS: A cross-sectional study was conducted, including 51 breast cancer survivors (BCS and 71 women without breast cancer, who were non-users of hormone therapy, tamoxifen, or aromatase inhibitors. BMD T-scores and measurements in grams per centimeter squared (g/cm² were obtained at the femoral neck, trochanter, Ward's triangle, and lumbar spine. Osteopenia and osteoporosis were grouped and categorized as abnormal BMD. Unconditional logistic regression analysis was used to estimate the odds ratios (OR of abnormal BMD values as measures of association, with 95% confidence intervals (CIs, adjusting for age, years since menopause, parity, and body mass index (BMI. RESULTS: The mean age of the women with and without breast cancer was 54.7 ± 5.8 years and 58.2 ± 4.8 years (p OBJETIVO: Comparar a densidade mineral óssea (DMO de mulheres na pós-menopausa com e sem câncer de mama. MÉTODOS: Conduziu-se estudo de corte transversal, incluindo 51 mulheres com câncer de mama e 71 mulheres sem câncer de mama, não usuárias de terapia hormonal, tamoxifeno ou de inibidores da aromatase. Avaliou-se a DMO, em T-score e em gramas por centímetro quadrado (g/cm², no colo do fêmur, trocânter, triângulo de Wards e na coluna lombar. Osteopenia e osteoporose foram agrupadas e categorizadas como DMO alterada. Utilizou-se a análise de regressão logística não condicional para estimar o odds ratios (OR de DMO alterada como medida de associação, com intervalo de confiança de 95% (IC 95%, ajustando-se por idade, anos de menopausa, paridade e índice de massa corpórea (IMC. RESULTADOS: A média de idade de mulheres com e sem câncer de mama foi 54,7 ± 5,8 anos e 58,2 ± 4,8 anos (p < 0,01, respectivamente. Após ajustar por idade, paridade e IMC, DMO alterada no colo do fêmur (OR ajustado: 4,8; IC 95%: 1,5-15,4, trocânter (OR

Pressure and partial wetting effects on superhydrophobic friction reduction in microchannel flow

Science.gov (United States)

Kim, Tae Jin; Hidrovo, Carlos

2012-11-01

Friction reduction in microchannel flows can help alleviate the inherently taxing pumping power requirements associated with the dimensions involved. One possible way of achieving friction reduction is through the introduction of surface microtexturing that can lead to a superhydrophobic Cassie-Baxter state. The Cassie-Baxter state is characterized by the presence of air pockets within the surface microtexturing believed to act as an effective "shear free" (or at least shear reduced) layer, decreasing the overall friction characteristics of the surface. Most work in this area has concentrated on optimizing the surface microtexturing geometry to maximize the friction reduction effects and overall stability of the Cassie-Baxter state. However, less attention has been paid to the effects of partially wetted conditions induced by pressure and the correlation between the liquid-gas interface location within the surface microtexturing and the microchannel flow characteristics. This is mainly attributed to the difficulty in tracking the interface shape and location within the microtexturing in the typical top-down view arrangements used in most studies. In this paper, a rectangular microchannel with regular microtexturing on the sidewalls is used to visualize and track the location of the air-water interface within the roughness elements. While visually tracking the wetting conditions in the microtextures, pressure drops versus flow rates for each microchannel are measured and analyzed in terms of the non-dimensional friction coefficient. The frictional behavior of the Poiseuille flow suggests that (1) the air-water interface more closely resembles a no-slip boundary rather than a shear-free one, (2) the friction is rather insensitive to the degree of microtexturing wetting, and (3) the fully wetted (Wenzel state) microtexturing provides lower friction than the non-wetted one (Cassie state), in corroboration with observations (1) and (2).

Relación entre síntomas autonómicos con niveles de ansiedad y depresión en mujeres con cáncer de mama

OpenAIRE

Sánchez Huerta, María Suhail; Figueroa López, Carlos Gonzalo; Cacho Díaz, Bernardo; Robles García, Rebeca

2016-01-01

Resumen: El cáncer de mama es una amenaza debido al estrés que confrontan las mujeres. Éstos pueden generar ansiedad, depresión e incluso, desregular el funcionamiento autonómico. Objetivo: evaluar la relación entre síntomas autonómicos y, síntomas de ansiedad y depresión en mujeres con cáncer de mama. Método: se evaluaron 59 mujeres a quienes se les aplicó el Perfil de Síntomas Autonómicos (PSA) y la Escala de Ansiedad y Depresión Hospitalaria (HADS). Resultados: el 49% y el 24% de las mujer...

The application of μPIV technique in the study of magnetic flows in a micro-channel

International Nuclear Information System (INIS)

Nguyen, N.T.; Wu, Z.G.; Huang, X.Y.; Wen, C.-Y..

2005-01-01

In this preliminary experimental study, micro-scale particle image velocimetry (μPIV) was adopted for the first time to get the quantitative information of magnetic flows in a micro-channel. The μPIV consists of an inverted florescent microscope, a Q-switch Nd:YAG laser and a CCD camera. The florescent liquid with particles of 3 μm diameter was blended homogeneously with the prepared magnetic fluid. A permanent magnet approached and left one end of the micro-channel. The response of the magnetic fluid was recorded with the μPIV simultaneously. The flow features validate the feasibility of using μPIV technique in the study of magnetic flows in a micro-channel. μPIV provides a promising experimental tool for visualization and quantitative measurement of magnetic micro-flows

AGULHA FINA DE MAMA E TIREOIDE

Directory of Open Access Journals (Sweden)

Ivone Rosini

2014-01-01

Full Text Available El estudio objetivó construir un protocolo de cuidados para punción aspirativa con aguja fina de mama y tiroides. Con abordaje cualitativo, tipo convergente asistencial. el estudio fue realizado en un hospital de enseñanza en el sur de Brasil, en el periodo septiembre de 2010 a abril de 2011. Participaron del estudio 88 clientes y 20 profesionales que actúan en el Servicio de Radiología. La construcción del protocolo ocurrió en tres etapas: realización de actividades educativas em sala de espera junto a los clientes para identificación de dudas y ansiedades acerca del examen, encuentros con los profesionales para evaluación y validación del protocolo y búsqueda de evidencias científicas en las fuentes de datos. La organización de lós datos ha permitido la elaboración del organigrama de atendimiento del cliente y el protocolo de cuidados, que fue organizado en actividades secuenciales incluyendo el ejecutor, actividad y justificativa científica. Los profesionales indicaron la importancia del protocolo, trayendo beneficios para la asistencia del cliente, como la agilidad, organización y humanización del atendimiento.

Pattern analysis of aligned nanowires in a microchannel

International Nuclear Information System (INIS)

Jeon, Young Jin; Kang, Hyun Wook; Ko, Seung Hwan; Sung, Hyung Jin

2013-01-01

An image processing method for evaluating the quality of nanowire alignment in a microchannel is described. A solution containing nanowires flowing into a microchannel will tend to deposit the nanowires on the bottom surface of the channel via near-wall shear flows. The deposited nanowires generally form complex directional structures along the direction of flow, and the physical properties of these structures depend on the structural morphology, including the alignment quality. A quantitative analysis approach to characterizing the nanowire alignment is needed to estimate the useful features of the nanowire structures. This analysis consists of several image processing methods, including ridge detection, texton analysis and autocorrelation function (ACF) calculation. The ridge detection method improved the ACF by extracting nanowire frames 1–2 pixels in width. Dilation filters were introduced to permit a comparison of the ACF results calculated from different images, regardless of the nanowire orientation. An ACF based on the FFT was then calculated over a square interrogation window. The alignment angle probability distribution was obtained using texton analysis. Monte Carlo simulations of artificially generated images were carried out, and the new algorithm was applied to images collected using two types of microscopy. (paper)

Osmotically driven flows in microchannels separated by a semipermeable membrane

DEFF Research Database (Denmark)

Jensen, Kåre Hartvig; Lee, J.; Bohr, Tomas

2009-01-01

We have fabricated lab-on-a-chip systems with microchannels separated by integrated membranes allowing for osmotically driven microflows. We have investigated these flows experimentally by studying the dynamics and structure of the front of a sugar solution travelling in 200 mu m wide and 50-200 mu...... m deep microchannels. We find that the sugar front travels at a constant speed, and that this speed is proportional to the concentration of the sugar solution and inversely proportional to the depth of the channel. We propose a theoretical model, which, in the limit of low axial flow resistance......, predicts that the sugar front should indeed travel with a constant velocity. The model also predicts an inverse relationship between the depth of the channel and the speed, and a linear relation between the sugar concentration and the speed. We thus find good qualitative agreement between the experimental...

Heat transfer and pressure drop in microchannels with random roughness

NARCIS (Netherlands)

Pelevic, N.; van der Meer, Theodorus H.

2016-01-01

The effect of surface roughness on heat transfer and fluid flow phenomena within a microchannel has been investigated by using the lattice Boltzmann method. The surface roughness has been generated by using Gaussian function. Gaussian function is an efficient and convenient method to create surface

Variation of microchannel plate resistance with temperature and applied voltage

International Nuclear Information System (INIS)

Pearson, J.F.; Fraser, G.W.; Whiteley, M.J.

1987-01-01

The resistance of microchannel plate electron multiplier is well known to be a function of both applied voltage and detector temperature. We show that the apparent variation of resistance with bias voltage is simply due to plate temperature increases resulting from resistive heating. (orig.)

Continuous particle focusing in a waved microchannel using negative dc dielectrophoresis

KAUST Repository

Li, Ming; Li, Shunbo; Cao, Wenbin; Li, Weihua; Wen, Weijia; Alici, Gursel

2012-01-01

We present a waved microchannel for continuous focusing of microparticles and cells using negative direct current (dc) dielectrophoresis. The waved channel is composed of consecutive s-shaped curved channels in series to generate an electric field

Air-side performance of a micro-channel heat exchanger in wet surface conditions

Directory of Open Access Journals (Sweden)

Srisomba Raviwat

2017-01-01

Full Text Available The effects of operating conditions on the air-side heat transfer, and pressure drop of a micro-channel heat exchanger under wet surface conditions were studied experimentally. The test section was an aluminum micro-channel heat exchanger, consisting of a multi-louvered fin and multi-port mini-channels. Experiments were conducted to study the effects of inlet relative humidity, air frontal velocity, air inlet temperature, and refrigerant temperature on air-side performance. The experimental data were analyzed using the mean enthalpy difference method. The test run was performed at relative air humidities ranging between 45% and 80%; air inlet temperature ranges of 27, 30, and 33°C; refrigerant-saturated temperatures ranging from 18 to 22°C; and Reynolds numbers between 128 and 166. The results show that the inlet relative humidity, air inlet temperature, and the refrigerant temperature had significant effects on heat transfer performance and air-side pressure drop. The heat transfer coefficient and pressure drop for the micro-channel heat exchanger under wet surface conditions are proposed in terms of the Colburn j factor and Fanning f factor.

Development of New Correlation and Assessment of Correlations for Two-Phase Pressure Drop in Rectangular Microchannels

International Nuclear Information System (INIS)

Choi, Chi Woong; Yu, Dong In; Kim, Moo Hwan

2010-01-01

There are two kinds of models in two-phase pressured drop; homogeneous flow model and separated flow model. Many previous researchers have developed correlations for two-phase pressure drop in a microchannel. Most correlations were modified Lockhart and Martinelli's correlation, which was based on the separated flow model. In this study, experiments for adiabatic liquid water and nitrogen gas flow in rectangular microchannels were conducted to investigate two-phase pressure drop in the rectangular microchannels. Two-phase frictional pressure drop in the rectangular microchannels is highly related with flow regime. Homogeneous model with six two-phase viscosity models: Owen(21)'s, MacAdams(22)'s, Cicchitti et al.(23)'s, Dukler et al.(24)'s, Beattie and Whalley(25)'s, Lin et al.(26)'s models and six separated flow models: Lockhart and Martinelli(27)'s, Chisholm(31)'s, Zhang et al.(15)'s, Lee and Lee(5)'s, Moriyama and Inue(4)'s, Qu and Mudawar(8)'s models were assessed with our experimental data. The best two-phase viscosity model is Beattie and Whalley's model. The best separated flow model is Qu and Mudawar's correlation. Flow regime dependency in both homogeneous and separated flow models was observed. Therefore, new flow pattern based correlations for both homogeneous and separated flow models were individually proposed

Theoretical modeling of electroosmotic flow in soft microchannels: A variational approach applied to the rectangular geometry

Science.gov (United States)

Sadeghi, Arman

2018-03-01

Modeling of fluid flow in polyelectrolyte layer (PEL)-grafted microchannels is challenging due to their two-layer nature. Hence, the pertinent studies are limited only to circular and slit geometries for which matching the solutions for inside and outside the PEL is simple. In this paper, a simple variational-based approach is presented for the modeling of fully developed electroosmotic flow in PEL-grafted microchannels by which the whole fluidic area is considered as a single porous medium of variable properties. The model is capable of being applied to microchannels of a complex cross-sectional area. As an application of the method, it is applied to a rectangular microchannel of uniform PEL properties. It is shown that modeling a rectangular channel as a slit may lead to considerable overestimation of the mean velocity especially when both the PEL and electric double layer (EDL) are thick. It is also demonstrated that the mean velocity is an increasing function of the fixed charge density and PEL thickness and a decreasing function of the EDL thickness and PEL friction coefficient. The influence of the PEL thickness on the mean velocity, however, vanishes when both the PEL thickness and friction coefficient are sufficiently high.

An experimental analysis of process parameters to manufacture micro-channels in AISI H13 tempered steel by laser micro-milling

Science.gov (United States)

Teixidor, D.; Ferrer, I.; Ciurana, J.

2012-04-01

This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.

Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

Science.gov (United States)

Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

2017-02-01

Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations.

Câncer de mama e sofrimento psicológico: aspectos relacionados ao feminino

OpenAIRE

Silva, Lucia Cecilia da

2008-01-01

No Brasil e no mundo a incidência do câncer de mama vem aumentando e aparecendo cada vez mais cedo na vida da mulher. O tratamento envolve mastectomia, quimioterapia e radioterapia, que, pelos seus efeitos físicos, podem comprometer em variados graus a auto-estima, a imagem corporal e a identidade feminina daquelas que recebem o diagnóstico da doença. Além disso, em nossa sociedade o câncer adquiriu significados relacionados a culpa, punição, deterioração, dor e morte, agravando o sofrimento ...

An analytical model for annular flow boiling heat transfer in microchannel heat sinks

International Nuclear Information System (INIS)

Megahed, A.; Hassan, I.

2009-01-01

An analytical model has been developed to predict flow boiling heat transfer coefficient in microchannel heat sinks. The new analytical model is proposed to predict the two-phase heat transfer coefficient during annular flow regime based on the separated model. Opposing to the majority of annular flow heat transfer models, the model is based on fundamental conservation principles. The model considers the characteristics of microchannel heat sink during annular flow and eliminates using any empirical closure relations. Comparison with limited experimental data was found to validate the usefulness of this analytical model. The model predicts the experimental data with a mean absolute error 8%. (author)

ATUAÇÃO FISIOTERAPÊUTICA EM PACIENTES PÓS-CIRURGIA DO CÂNCER DE MAMA: UMA REVISÃO BIBLIOGRÁFICA

Directory of Open Access Journals (Sweden)

Denilson de Queiroz Cerdeira

2014-06-01

Full Text Available O câncer de mama é a neoplasia de maior ocorrência entre as mulheres, sendo considerado um problema de saúde pública. Consequentemente é uma das causas de morbidade e mortalidade na mulher. Objetivou-se buscar informações sobre a atuação da Fisioterapia em pacientes pós-cirurgia de câncer de mama, conhecendo os aspectos desta atuação e como tem sido empregado na documentação bibliográfica. Tratou-se de uma pesquisa bibliográfica no período correspondente aos últimos 15 anos (1998 a 2013, nas bases Medline, Lilacs, Scielo, Pubmed e PEDro, utilizando-se as palavras chave: Oncologia, Fisioterapia, Reabilitação, Mastectomia. Foram incluídos na pesquisa estudos de sujeitos com idade superior a 18 anos, idioma inglês, português e espanhol. Foram excluídos artigos que não descreviam a atuação da Fisioterapia adequadamente e estudos de casos. Foram encontrados 337 artigos, dos quais 30 foram selecionados, sendo 08 artigos de revisão, 13 estudos transversais e 09 ensaios clínicos. A revisão de literatura evidenciou a importância do tratamento fisioterapêutico em pacientes no pós - operatório de câncer de mama. Os estudos demonstram que a Fisioterapia desempenha um papel fundamental na prevenção ou diminuição de possíveis sequelas advindas do pós-operatório, como complicações respiratórias, circulatórias e osteomioarticulares.

Surface Modification of SiO2 Microchannels with Biocompatible Polymer Using Supercritical Carbon Dioxide

Science.gov (United States)

Saito, Tatsuro; Momose, Takeshi; Hoshi, Toru; Takai, Madoka; Ishihara, Kazuhiko; Shimogaki, Yukihiro

2010-11-01

The surface of 500-mm-long microchannels in SiO2 microchips was modified using supercritical CO2 (scCO2) and a biocompatible polymer was coated on it to confer biocompatibility to the SiO2 surface. In this method, the SiO2 surface of a microchannel was coated with poly(ethylene glycol monomethacrylate) (PEGMA) as the biocompatible polymer using allyltriethoxysilane (ATES) as the anchor material in scCO2 as the reactive medium. Results were compared with those using the conventional wet method. The surface of a microchannel could not be modified by the wet method owing to the surface tension and viscosity of the liquid, but it was modified uniformly by the scCO2 method probably owing to the near-zero surface tension, low viscosity, and high diffusivity of scCO2. The effect of the surface modification by the scCO2 method to prevent the adsorption of protein was as high as that of the modification by the wet method. Modified microchips can be used in biochemical and medical analyses.

Self-Sealed Bionic Long Microchannels with Thin Walls and Designable Nanoholes Prepared by Line-Contact Capillary-Force Assembly.

Science.gov (United States)

Lao, Zhao-Xin; Hu, Yan-Lei; Pan, Deng; Wang, Ren-Yan; Zhang, Chen-Chu; Ni, Jin-Cheng; Xu, Bing; Li, Jia-Wen; Wu, Dong; Chu, Jia-Ru

2017-06-01

Long microchannels with thin walls, small width, and nanoholes or irregular shaped microgaps, which are similar to capillaries or cancerous vessels, are urgently needed to simulate the physiological activities in human body. However, the fabrication of such channels remains challenging. Here, microchannels with designable holes are manufactured by combining laser printing with line-contact capillary-force assembly. Two microwalls are first printed by femtosecond laser direct-writing, and subsequently driven to collapse into a channel by the capillary force that arises in the evaporation of developer. The channel can remain stable in solvent due to the enhanced Van der Waals' force caused by the line-contact of microwalls. Microchannels with controllable nanoholes and almost arbitrary patterns can be fabricated without any bonding or multistep processes. As-prepared microchannels, with wall thicknesses less than 1 µm, widths less than 3 µm, lengths more than 1 mm, are comparable with human capillaries. In addition, the prepared channels also exhibit the ability to steer the flow of liquid without any external pump. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crossflow type silicon microchannel substrate monodispersion oil-in-water emulsion manufacture; Kurosufuro gata shirikon maikuro chaneru kiban wo mochiita tanbunsan suchuyu emarushon no sakusei

Energy Technology Data Exchange (ETDEWEB)

Kawakatsu, Takahiro [Tohoku University, Miyagi (Japan). Graduate School; Komori, Hideai; Najima, Mitsutashi; Kikuchi, Yuji; Yonemoto, Toshikuni

1999-05-05

The new technique, which continuously produced the monodispersion oil-in-water (0/W) emulsion using the crossflow type silicon microchannel substrate, was developed. On the silicon monocrystal substrate, the watercourse as the liquid of the continuous phase flowed was produced, and the column of the equal slit of the size in both walls of the watercourse was precisely processed. By closing the upper part in the slit by the clamp of the flat glass board in the microchannel substrate, the microchannel column was formed. Through the microchannel, the oil droplet in which the size was even was formed by sending out the oil (triolein) in the water (0.3wt% sodium lauryl sulfate aqueous solution) of continuous phase which is flowing in respect of the watercourse. The size of the oil droplet is greatly dependent on the structure of the microchannel regulated by microchannel width, microchannel height and terrace length (the even part of which the microchannel exit was equipped). Monodispersion emulsion of 16,20 and 48 {mu}m at the average droplet diameter was formed by using microchannel substrate of the three types of which the structure differs. Droplet diameter decreased, when the substrate which formed large droplet of 48 {mu}m in which the water current quantity is 1.4x10{sup -2}mLmin{sup -1} was used, when the flow rate increased. However, there was no a flow rate at droplet diameter, even if it was made to change from 1.4x10{sup -2} to 2.4mLmin{sup -1}, 16 {mu}m 20 {mu}m small change. In all cases, the droplet size distribution was narrow, and the geometry standard deviation was under 1.03. (translated by NEDO)

Carcinoma medular da mama: correlação anátomo-radiológica

OpenAIRE

Matheus,Valéria Soares; Kestelman,Fabíola Procaci; Canella,Ellyete de Oliveira; Djahjah,Maria Célia Resende; Koch,Hilton Augusto

2008-01-01

OBJETIVO: Avaliar as características radiológicas do câncer de mama medular em pacientes submetidas a tratamento cirúrgico no Instituto Nacional de Câncer (INCA) - Ministério da Saúde, Rio de Janeiro, RJ, correlacionando os achados com estudo histopatológico. MATERIAIS E MÉTODOS: Foi realizado estudo descritivo retrospectivo de mulheres submetidas a tratamento cirúrgico no INCA, no período de janeiro de 1997 a dezembro de 2006, para identificação das pacientes com carcinoma medular e análise ...

Protagonismo del sistema inmune en el microambiente de los tumores malignos de la mama

OpenAIRE

Arango Prado, María del Carmen; Rodríguez-Padilla, Cristina

2016-01-01

Los avances recientes en la comprensión de los mecanismos génicos y moleculares del cáncer de mama han revelado que el sistema inmune protagoniza los eventos responsables del desarrollo y la progresión del tumor. Las células de la respuesta inmune innata y adaptativa, así como diversos mediadores solubles liberados por ellas, pueden establecer una respuesta antitumoral protectora o, por el contrario, inducir eventos de inflamación crónica que favorezcan la promoción y progresión de esta enfer...

Flow analysis for efficient design of wavy structured microchannel mixing devices

Science.gov (United States)

Kanchan, Mithun; Maniyeri, Ranjith

2018-04-01

Microfluidics is a rapidly growing field of applied research which is strongly driven by demands of bio-technology and medical innovation. Lab-on-chip (LOC) is one such application which deals with integrating bio-laboratory on micro-channel based single fluidic chip. Since fluid flow in such devices is restricted to laminar regime, designing an efficient passive modulator to induce chaotic mixing for such diffusion based flow is a major challenge. In the present work two-dimensional numerical simulation of viscous incompressible flow is carried out using immersed boundary method (IBM) to obtain an efficient design for wavy structured micro-channel mixing devices. The continuity and Navier-Stokes equations governing the flow are solved by fractional step based finite volume method on a staggered Cartesian grid system. IBM uses Eulerian co-ordinates to describe fluid flow and Lagrangian co-ordinates to describe solid boundary. Dirac delta function is used to couple both these co-ordinate variables. A tether forcing term is used to impose the no-slip boundary condition on the wavy structure and fluid interface. Fluid flow analysis by varying Reynolds number is carried out for four wavy structure models and one straight line model. By analyzing fluid accumulation zones and flow velocities, it can be concluded that straight line structure performs better mixing for low Reynolds number and Model 2 for higher Reynolds number. Thus wavy structures can be incorporated in micro-channels to improve mixing efficiency.

Pool boiling visualization on open microchannel surfaces

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Kaniowski Robert

2017-01-01

Full Text Available The paper presents visualization investigations into pool boiling heat transfer for open minichannel surfaces. The experiments were carried out wih saturated water at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.3 mm wide and 0.2 to 0.4 mm deep. High-speed videos were used as an aid to understanding the heat transfer mechanism. The visualization study aimed at identifying nucleation sites of the departing bubbles and determining their diameters and frequency at various superheats.

Características de pacientes con cáncer de mama diagnosticado en el año 2013 en el municipio de Las Tunas

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Enrique Nicolás Milián Mosquera

2015-06-01

Full Text Available Fundamento: el cáncer de mama constituye la primera causa de muerte de las mujeres en el mundo. El diagnostico precoz y el tratamiento oportuno de las lesiones mamarias constituyen pilares fundamentales en la evolución y pronóstico de este tipo de cáncer. Objetivo: describir las características clínico-epidemiológicas de las pacientes con cáncer de mama del municipio de Las Tunas, provincia del mismo nombre, Cuba; en el periodo de enero a diciembre de 2013. Métodos: se realizó un estudio observacional-descriptivo y transversal. La población de estudio estuvo constituida por las 59 pacientes que se les diagnosticó cáncer de mama. Se estudiaron los antecedentes patológicos personales, antecedentes patológicos familiares de patología mamaria, menopausia, ingestión de hormonas y otros factores asociados. Se definió el BIRADS (por las siglas en inglés de Breast Imaging reporting and data system mamográfico y se determinó la etapa clínica en que estaban las pacientes cuando se realizó el diagnóstico. Para la recolección de la información fueron utilizados datos estadísticos, historias clínicas individuales, hojas de cargo y resultados de las biopsias y se procesaron por el método estadístico porcentual. Resultados: en la muestra predominó el grupo de edad entre los 50-59 años, los principales factores de riesgo asociados estuvieron relacionados con los antecedentes familiares de haber padecido esta enfermedad, la categoría mamográfica predominante fue la BIRADS IV, y la etapa clínica II. Conclusiones: el mayor por ciento de pacientes se diagnosticó de forma tardía, a pesar de los esfuerzos del sistema nacional de salud para aumentar la pesquisa del cáncer de mama.

Conhecimento sobre o diagnóstico e rastreamento do câncer de mama entre os ginecologistas do estado de Goiás (Brasil

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Freitas Júnior Ruffo de

2003-01-01

Full Text Available OBJETIVOS: Avaliar o nível de conhecimento sobre o rastreamento e diagnóstico do câncer de mama entre os ginecologistas do Estado de Goiás, Brasil. MÉTODOS: Foi enviado um questionário contendo perguntas sobre a formação profissional e sobre o diagnóstico do câncer de mama, para os 427 sócios da Sociedade Goiana de Ginecologia e Obstetrícia, entre maio e julho de 1999. RESULTADOS: Dos 427 questionários enviados, 26 (6% foram devolvidos por endereçamento incorreto. Dos 401 médicos que receberam o questionário, 85 (21% responderam e retornaram. Destes, 28% eram do sexo feminino, a média do tempo de profissão foi de 17 anos e 70% possuía a residência médica como maior titularidade. A média de idade foi de 44 anos. As taxas de respostas corretas foram: 94% sabiam o sinal mais freqüente do câncer de mama, 75% o melhor método para rastreamento, 88% o período de quando iniciar a mamografia, 93% a periodicidade da mamografia após os 50 anos e 83% sobre a indicação da ultra-sonografia complementar. O fato de o profissional ter cursado um programa de Residência Médica foi o único fator que influenciou na taxa de respostas corretas, se comparado àqueles que não cursaram. O sexo do profissional, portadores de Título de Especialista em ginecologia e obstetrícia (TEGO e a cidade de atuação não influenciaram nas taxas de respostas corretas. CONCLUSÕES: Os ginecologistas do Estado de Goiás que responderam ao questionário têm um bom conhecimento sobre o rastreamento e diagnóstico do câncer de mama, sendo que apenas a Residência Médica influenciou na taxa de respostas corretas.

Two-phase flow regimes in a horizontal microchannel with the height of 50 μm and width of 10 mm

Science.gov (United States)

Fina, V. P.; Ronshin, F. V.

2017-11-01

Two-phase flows of distilled deionized nanofiltered water and nitrogen gas in a microchannel with a height of 50 μm and a width of 10 mm have been investigated experimentally. The schlieren method has been used to determine main features of the two-phase flow in the microchannel. This method allows detecting the liquid film on the lower and upper walls of the microchannel as well as droplets of various shapes and sizes or vertical liquid bridges. Two-phase flow regimes have been observed, and their boundaries precisely determined using post-processing of the recordings. The following flow regimes have been distinguished: bubble, churn, jet, stratified and annular. Comparison of regime maps for channels of different widths has been carried out, and this parameter showed to have a significant impact on the boundaries between the regimes in microchannels of a height of less than 100 μm.

Nuevas contribuciones en la fisioterapia del linfedema de miembro superior secundario al tratamiento del cáncer de mama

OpenAIRE

Canet Pérez, Cristina; Santandreu Mañó, Trinidad; Nácher Nebot, Rosa

2011-01-01

Resumen del póster presentado en las II Jornadas de Fisioterapia en Lesiones del Sistema Músculo-esquelético: miembro superior. Escuela Universitaria de Fisioterapia Universitat de València 28 y 29 abril de 2011 Introducción. El linfedema supone un importante problema en mujeres tratadas de cáncer de mama. Distintas revisiones han puesto...

Riesgo familiar total en familias con mujeres diagnosticadas con neoplasia de mama

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Nancy Cecilia Charrys-Bravo

2017-07-01

Full Text Available Objetivo: Determinar el riesgo familiar total de las familias con mujeres diagnosticadas con cáncer de mama, que asisten a un centro de salud oncológico en la ciudad de Barranquilla. Materiales y Métodos: El estudio fue de tipo descriptivo, transversal con abordaje cuantitativo. Se utilizó el instrumento Riesgo Familiar Total RFT 5-33. El universo estuvo conformado por familias con mujeres diagnosticadas con cáncer en mama. La muestra fue de 41 familias que integraron a 154 miembros; se abordó el estudio de manera censal, y no por medio de una muestra, porque el acceso a la información de la totalidad de las familia fue viable. Resultados: Los resultados mostraron que las familias, en su mayoría, son de tipo 2. El 68 % de las pacientes categorizan sus familias como amenazadas, el 5 % como familias de alto riesgo y un 27 % de las familias con un bajo riesgo. Conclusiones: Los hallazgos encontrados en esta investigación son importantes para las familias, lo cual permitirá establecer acciones y actividades que logren orientar e implementar procesos de atención específicos con el propósito de cuidar a las familias para que se mantengan sanos en un nivel de bajo riesgo; además, desarrollar controles y seguimiento a aquellas familias que se encuentran en un riesgo alto de amenazas, mediante acciones de promoción y prevención de la enfermedad de una manera amplia. Por lo anterior, se deben emprender programas más agresivos de prevención y promoción, especialmente con las familias que asisten en busca de apoyo médico para este padecimiento; de esta forma, se podrán diagnosticar los casos de forma temprana y proceder al respectivo tratamiento.

Fabrication of Super-Hydrophobic Microchannels via Strain-Recovery Deformations of Polystyrene and Oxygen Reactive Ion Etch.

Science.gov (United States)

Chakraborty, Anirban; Xiang, Mingming; Luo, Cheng

2013-08-19

In this article, we report a simple approach to generate micropillars (whose top portions are covered by sub-micron wrinkles) on the inner surfaces of polystyrene (PS) microchannels, as well as on the top surface of the PS substrate, based on strain-recovery deformations of the PS and oxygen reactive ion etch (ORIE). Using this approach, two types of micropillar-covered microchannels are fabricated. Their widths range from 118 μm to 132 μm, depths vary from 40 μm to 44 μm, and the inclined angles of their sidewalls are from 53° to 64°. The micropillars enable these microchannels to have super-hydrophobic properties. The contact angles observed on the channel-structured surfaces are above 162°, and the tilt angles to make water drops roll off from these channel-structured substrates can be as small as 1°.

Fabrication of Super-Hydrophobic Microchannels via Strain-Recovery Deformations of Polystyrene and Oxygen Reactive Ion Etch

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Anirban Chakraborty

2013-08-01

Full Text Available In this article, we report a simple approach to generate micropillars (whose top portions are covered by sub-micron wrinkles on the inner surfaces of polystyrene (PS microchannels, as well as on the top surface of the PS substrate, based on strain-recovery deformations of the PS and oxygen reactive ion etch (ORIE. Using this approach, two types of micropillar-covered microchannels are fabricated. Their widths range from 118 μm to 132 μm, depths vary from 40 μm to 44 μm, and the inclined angles of their sidewalls are from 53° to 64°. The micropillars enable these microchannels to have super-hydrophobic properties. The contact angles observed on the channel-structured surfaces are above 162°, and the tilt angles to make water drops roll off from these channel-structured substrates can be as small as 1°.

Roles de género tradicionales y personalidad tipo c en mujeres con diagnóstico de cáncer de mama

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Marina Ceballos-Fontes

2016-01-01

Full Text Available Se identifica el desarrollo de la personalidad tipo c mediante procesos de socialización que fomentan roles normatizados de género y la relación de éstos con el cáncer de mama. Se entrevistaron mujeres diagnosticadas con esta enfermedad utilizando el método interpretativo para el análisis de datos. Los resultados mostraron relación entre los elementos descritos al encontrarse que la necesidad de armonía es el elemento prevaleciente de este constructo de personalidad que incide negativamente en prácticas de autocuidado, tales como la autoexploración mamaria y la asistencia oportuna al médico. Por ello, se proponen acciones desde la práctica psicológica que permitan promover el autocuidado enfocado en la prevención oportuna del cáncer de mama.

Tumor neuroendocrino de la mama. Presentación de un caso y revisión de la literatura

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Lidia Torres Aja

2017-04-01

Full Text Available Los carcinomas neuroendocrinos primarios de mama son neoplasias raras que representan entre un 2 y un 5 % de los tumores mamarios. Para su diagnóstico se requiere que más del 50 % del tumor presente marcadores neuroendocrinos. Estos tumores que se observan principalmente en mujeres de edad avanzada se presentan como una masa bien delimitada, generalmente no acompañada de adenopatías axilares. El pronóstico de este tipo de cáncer todavía no está muy claro, aunque estudios recientes demuestran que es similar al de los carcinomas ductales infiltrantes convencionales. Se presenta el caso de una paciente de 76 años que acudió a consulta por presentar gran tumoración que ocupaba prácticamente toda la mama derecha sin adenopatías axilares y la cual fue informada mediante biopsia por parafina como un carcinoma neuroendocrino. Este es el primer tumor de esta característica histológica diagnosticado en Cienfuegos, por lo cual se considera de interés científico su publicación.

Perfil de risco imunológico de idosas com câncer de mama: os primeiros 37 casos = Immune risk profile of elderly women with breast cancer: the first 37 cases

Directory of Open Access Journals (Sweden)

Vollbrecht, Betina

2014-01-01

Conclusões: A relação das células T CD4+/CD8+ parece aumentar nos casos de câncer de mama de pior prognóstico. Tanto quanto foi possível pesquisar na literatura, estes são os primeiros dados sobre células T CD4+ e CD8+ no sangue periférico de mulheres idosas com câncer de mama. Um seguimento maior poderá determinar o valor destas células como fator prognóstico e/ou preditivo

Barreras de acceso a los servicios de salud: narrativas de mujeres con cáncer de mama en Colombia

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Celmira Laza V.

2014-09-01

Full Text Available Resumen Objetivo: explorar la existencia de barreras de acceso a los servicios de salud en las historias de mujeres con cáncer de mama, que han recibido apoyo de seis ong colombianas. Metodología: se llevó a cabo un estudio cualitativo descriptivo interpretativo, en cinco ciudades colombianas: Bogotá, Medellín, Cali, Valledupar y Santa Marta, incluyendo 44 mujeres apoyadas por seis ong. Se realizaron grupos focales y entrevistas en profundidad. Resultados: en el proceso emergieron cuatro categorías: barreras ligadas a los determinantes estructurales, barreras originadas en los determinantes intermedios, herramientas para enfrentar las barreras y una categoría que hace referencia a la oportunidad de obtener un diagnóstico y un tratamiento de cáncer de mama. A partir de estas categorías, se propone un modelo de barreras de acceso en cáncer de mama, desde la perspectiva de los determinantes sociales. Discusión: a pesar de los esfuerzos del país por mejorar la oportunidad en prevención, diagnóstico y tratamiento del cáncer —incluyendo la promulgación de la ley 1384 de 2010 (Ley Sandra Ceballos—, las mujeres con cáncer de mama enfrentan barreras de acceso a los servicios de salud, que están determinadas socialmente, y frente a las cuales el sistema muestra cierto nivel de incapacidad. Abstract Objective: to explore the existence of barriers to healthcare access in the narratives of women with breast cancer who have received the support of six Colombian NGOs. Methodology: a descriptive qualitative interpretive study was carried out in five Colombian cities: Bogotá, Medellín, Cali, Santa Marta and Valledupar. Data was collected through focus groups and interviews with 44 women supported by six NGOs. Results: in the process, four categories emerged: barriers linked to structural determinants, barriers arising from intermediate determinants, tools to address barriers and a category referring to the opportunity for diagnosis and

Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

Energy Technology Data Exchange (ETDEWEB)

Flaschel, Nils; Ariza, Dario; Diez, Sergio; Gregor, Ingrid-Maria; Tackmann, Kerstin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gerboles, Marta; Jorda, Xavier; Mas, Roser; Quirion, David; Ullan, Miguel [Centro Nacional de Microelectronica, Barcelona (Spain)

2017-01-15

Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics. Today's prospects of micro-fabricating silicon opens a door to a more direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. In this paper, we are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype optimized to achieve a homogeneous flow distribution. Furthermore, the device was simulated using finite element methods.

Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

International Nuclear Information System (INIS)

Flaschel, Nils; Ariza, Dario; Diez, Sergio; Gregor, Ingrid-Maria; Tackmann, Kerstin; Gerboles, Marta; Jorda, Xavier; Mas, Roser; Quirion, David; Ullan, Miguel

2017-01-01

Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics. Today's prospects of micro-fabricating silicon opens a door to a more direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. In this paper, we are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype optimized to achieve a homogeneous flow distribution. Furthermore, the device was simulated using finite element methods.

Neural growth into a microchannel network: towards a regenerative neural interface

NARCIS (Netherlands)

Wieringa, P.A.; Wiertz, Remy; le Feber, Jakob; Rutten, Wim

2009-01-01

We propose and validated a design for a highly selective 'endcap' regenerative neural interface towards a neuroprosthesis. In vitro studies using rat cortical neurons determine if a branching microchannel structure can counter fasciculated growth and cause neurites to separte from one another,

Numerical study on drag reduction and heat transfer enhancement in microchannels with superhydrophobic surfaces for electronic cooling

International Nuclear Information System (INIS)

Cheng, Yongpan; Xu, Jinliang; Sui, Yi

2015-01-01

Microchannels with superhydrophobic surfaces are a promising candidate for electric cooling with mild frictional penalty. Frictional and thermal performance of laminar liquid-water flow in such microchannels is numerically investigated for various shear-free fractions and Reynolds numbers. The structures on superhydrophobic surfaces include square posts and holes, transverse and longitudinal grooves. Combined frictional and thermal performance of microchannels is evaluated by a goodness factor, and is compared with that of smooth plain channels. It is found that with increasing shear-free fractions, both friction factor and average Nusselt number deteriorate for four surface patterns; however, goodness factor is improved significantly over smooth plain channels. In general, superhydrophobic surfaces containing longitudinal and transverse grooves exhibit the lowest and highest frictional and thermal performance, respectively; however, combined performance of these two are on opposite. Among four surface patterns, longitudinal grooves have the highest goodness factors, except at high shear-free fractions or high Reynolds numbers where overall performance is surpassed by square posts. At very low or high shear-free fractions, frictional and thermal performance of two-dimensional square posts and holes approaches that of one-dimensional longitudinal or transverse grooves. Our study suggests microchannels with superhydrophobic surfaces as promising candidates for efficient cooling devices.

Behaviour and design considerations for continuous flow closed-open-closed liquid microchannels.

Science.gov (United States)

Melin, Jessica; van der Wijngaart, Wouter; Stemme, Göran

2005-06-01

This paper introduces a method of combining open and closed microchannels in a single component in a novel way which couples the benefits of both open and closed microfluidic systems and introduces interesting on-chip microfluidic behaviour. Fluid behaviour in such a component, based on continuous pressure driven flow and surface tension, is discussed in terms of cross sectional flow behaviour, robustness, flow-pressure performance, and its application to microfluidic interfacing. The closed-open-closed microchannel possesses the versatility of upstream and downstream closed microfluidics along with open fluidic direct access. The device has the advantage of eliminating gas bubbles present upstream when these enter the open channel section. The unique behaviour of this device opens the door to applications including direct liquid sample interfacing without the need for additional and bulky sample tubing.

Evaluation of a X-ray imaging method in micro-fluidics: the case of T-shaped micro-channels filling up

International Nuclear Information System (INIS)

Vabre, A.; Legoupil, S.; Manach, E.; Gal, O.; Colin, St.; Geoffroy, S.; Gue, A.M.

2006-01-01

X-rays methods assessment in micro-fluidics: case of 'T' shaped microchannels filling. Fluid flows within 'T' or 'Y' shaped microchannels are deeply studied in order to develop adapted modeling approaches and experimental techniques. Our technological choice lies on the attenuation measurement of X-ray in matter. The main advantage of this non-intrusive technique is to be implemented on media opaque to visible light. Moreover, X-rays methods may achieve better spatial resolutions as compared to optical methods because of their much lower wavelength. In order to validate this X-ray method, measurements obtained by this technique are compared with direct measurements carried out on similar microchannels. Finally, experimental results are compared with a theoretical model. (author)

Fasceíte necrotizante da mama: relato de caso Necrotizing fasciitis of the breast: case report

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Marco Aurélio da Costa Silva

1998-05-01

Full Text Available É apresentado um caso de fasceíte necrotizante, na mama, em uma paciente de 68 anos que foi submetida à excisão de um volumoso lipoma mamário e evoluiu com infecção local agressiva, apresentando necrose extensa do parênquima da mama e de suas fáscias, além da pele, quadro este que caracteriza as fasceítes. O trabalho chama a atenção para a gravidade da entidade e a dificuldade diagnóstica, em razão do comprometimento cutâneo mais tardio e menos extenso; enfatiza-se a necessidade de afastar tal diagnóstico na vigência de infecções mamárias, assim como ter uma abordagem precoce e agressiva na presença de um quadro de fasceíte necrotizante mamária.A case of postsurgical necrotizing fasciitis is presented. A 68-year-old female patient was submitted to a lumpectomy for a big breast lipoma. After surgen there was an aggressive local infection, with extensive necrosis of the breast tissue, including the superficial and deep fasciae and also the skin over the breast. The gravity of the disease and the difficulties in its diagnosis due to the late skin necrosis are emphasized. Under such circunstances an early and aggressive approach is necessary.

Surface cell immobilization within perfluoroalkoxy microchannels

Energy Technology Data Exchange (ETDEWEB)

Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

2014-11-30

Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

Stability Analysis of Reactive Multiphase Slug Flows in Microchannels

Directory of Open Access Journals (Sweden)

Alejandro A. Munera Parra

2014-05-01

Full Text Available Conducting multiphase reactions in micro-reactors is a promising strategy for intensifying chemical and biochemical processes. A major unresolved challenge is to exploit the considerable benefits offered by micro-scale operation for industrial scale throughputs by numbering-up whilst retaining the underlying advantageous flow characteristics of the single channel system in multiple parallel channels. Fabrication and installation tolerances in the individual micro-channels result in different pressure losses and, thus, a fluid maldistribution. In this work, an additional source of maldistribution, namely the flow multiplicities, which can arise in a multiphase reactive or extractive flow in otherwise identical micro-channels, was investigated. A detailed experimental and theoretical analysis of the flow stability with and without reaction for both gas-liquid and liquid-liquid slug flow has been developed. The model has been validated using the extraction of acetic acid from n-heptane with the ionic liquid 1-Ethyl-3-methylimidazolium ethyl sulfate. The results clearly demonstrate that the coupling between flow structure, the extent of reaction/extraction and pressure drop can result in multiple operating states, thus, necessitating an active measurement and control concept to ensure uniform behavior and optimal performance.

Preliminary studies of microchannel plate photomultiplier tube neutron detectors for flight test applications

International Nuclear Information System (INIS)

Dolan, K.W.

1978-10-01

Electrical, mechanical, thermal, and neutron response data indicate that microchannel plate photomultiplier tubes are viable candidates as miniature, ruggedized neutron detectors for flight test applications in future weapon systems

Theoretical study of time-dependent, ultrasound-induced acoustic streaming in microchannels

DEFF Research Database (Denmark)

Muller, Peter Barkholt; Bruus, Henrik

2015-01-01

Based on first- and second-order perturbation theory, we present a numerical study of the temporal buildup and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic...

Optical fibre cavity ring down measurement of refractive index with a microchannel drilled by femtosecond laser

Science.gov (United States)

Zhou, Kaiming; Webb, David; Mou, Chengbo; Farries, Mark; Hayes, Neil; Bennion, Ian

2009-10-01

μA microchannel was inscribed in the fibre of a ring cavity which was constructed from two 0.1%:99.9% couplers and a 10m fibre loop. Cavity ring down spectroscopy (CRDS) was used to measure the refractive index (RI) of gels infused into the microchannel with high resolution. The ring down time discloses a nonlinear increase with respect to the RI of the gel and sensitivity up to 300μs/RI unit (RIU) and resolution of 5×10-4 were obtained.

Prognosis of breast cancer during pregnancy: evidence for nursing care El pronóstico de cáncer de mama en el embarazo: evidencias para la atención de enfermería O prognóstico de câncer de mama na gravidez: evidências para o cuidado de enfermagem

Directory of Open Access Journals (Sweden)

Ana Fátima Carvalho Fernandes

2011-12-01

Full Text Available This integrative review analyzed evidence available in the literature concerning the prognosis of breast cancer during pregnancy. The following databases were used for selecting studies: PubMed, CINAHL and LILACS. A total of 240 primary studies were identified; 13 papers were included in the integrative review’s sample after reading the titles and abstracts and according to the established inclusion and exclusion criteria. There is evidence indicating that pregnancy does not worsen the evolution of breast cancer and a poor prognosis is related to late stage tumors. Among the gaps identified in the studied theme, the need for further studies addressing nursing care provided to pregnant women with breast cancer is highlighted in order to promote improved care in the context of health care.Esta revisión integradora de la literatura objetivó analizar las evidencias disponibles en la literatura sobre el pronóstico del cáncer de mama durante el embarazo. La selección de los estudios primarios fue realizada en las bases de datos PubMed, CINAHL y LILACS; se identificaron 240 estudios primarios. Después de la lectura de los títulos y resúmenes y establecimiento de los criterios de inclusión y exclusión, 13 artículos fueron incluidos en la muestra de la revisión integradora. En la síntesis del conocimiento producido hay evidencias que indican que el embarazo no empeora la evolución del cáncer de mama y el pronóstico malo está relacionado con la estadificación clínica tardía del tumor. Entre las lagunas en el tópico investigado hay que resaltar la necesidad de realizar estudios sobre la atención de enfermería prestada a mujeres embarazadas con cáncer de mama para mejoría del cuidado en el contexto de la atención a la salud.O presente estudo teve como objetivo analisar as evidências disponíveis na literatura sobre o prognóstico de câncer de mama na gravidez. O método de revisão adotado foi a revisão integrativa. Para a

Flow Investigation in a Microchannel with a Flow Disturbing Rib

Czech Academy of Sciences Publication Activity Database

Stogiannis, I.A.; Passos, A.D.; Mouza, A.A.; Paras, S.V.; Pěnkavová, Věra; Tihon, Jaroslav

2014-01-01

Roč. 119, NOV 8 (2014), s. 65-76 ISSN 0009-2509 R&D Projects: GA ČR(CZ) GAP101/12/0585; GA MŠk 7AMB12GR018 Institutional support: RVO:67985858 Keywords : microchannel * wall shear stress * micro-PIV Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.337, year: 2014

Experimental investigation of thermoelectric power generation versus coolant pumping power in a microchannel heat sink

DEFF Research Database (Denmark)

Kolaei, Alireza Rezania; Rosendahl, Lasse; Andreasen, Søren Juhl

2012-01-01

The coolant heat sinks in thermoelectric generators (TEG) play an important role in order to power generation in the energy systems. This paper explores the effective pumping power required for the TEGs cooling at five temperature difference of the hot and cold sides of the TEG. In addition......, the temperature distribution and the pressure drop in sample microchannels are considered at four sample coolant flow rates. The heat sink contains twenty plate-fin microchannels with hydraulic diameter equal to 0.93 mm. The experimental results show that there is a unique flow rate that gives maximum net-power...

Interferometric measurement and numerical comparisons of supersonic heat transfer flows in microchannel

International Nuclear Information System (INIS)

Takahashi, Yuya; Chen, Lin; Okajima, Junnosuke; Iga, Yuka; Komiya, Atsuki; Maruyama, Shigenao

2016-01-01

Highlights: • Effective cooling design by super-/sub-sonic air flow in microchannels is proposed. • Microscale supersonic flows is successfully generated and examined. • Microchannel flow density field were visualized quantitatively by interferometer. • The bump design shows great potential of heat transfer enhancement in microscale. - Abstract: With the fast development of electronic systems and the ever-increasing demand of thermally “smart” design in space and aeronautic engineering, the heat transfer innovations and high heat flux challenges have become a hot topic for decades. This study is aimed at the effective cooling heat transfer design by super-/sub-sonic air flow in microscale channels for high heat flux devices. The design is based on the low temperature flows with supersonic expansion in microscale, which yields a compact and simple design. By careful microelectromechanical process, microscale straight and bumped channels (with simple arc curve) are fabricated and experimentally tested in this study. The microscale flow field and density distributions under new designs are visualized quantitatively by an advanced phase-shifting interferometer system, which results are then compared carefully with numerical simulations. In this study, large differences between the two designs in density distribution and temperature changes (around 50 K) are found. The high heat flux potential for supersonic microchannel flows is realized and discussion into detail. It is confirmed that the bump design contributes significantly to the heat transfer enhancement, which shows potential for future application in novel system designs.

Determination of the Navier slip coefficient of microchannels exploiting the streaming potential.

Science.gov (United States)

Park, Hung Mok

2012-03-01

For most microchannels made of hydrophobic materials such as polymers, velocity slip occurs at the wall, affecting volumetric flow rate of electroosmotic flow Q(eof) and streaming potential (∂ϕ(str)/∂z). Since most techniques exploit Q(eof) or (∂ϕ(str)/∂z) to determine the zeta potential, ζ, it is very difficult to measure ζ of hydrophobic walls, if the slip coefficient b is not found a priori. Until now, Q(eof) and (∂ϕ(str)/∂z) are known to depend on ζ and b in a same functional form, which makes it impossible to estimate ζ or b separately using measurements of Q(eof) and (∂ϕ(str)/∂z). However, exploiting the analytic formula for Q(eof) and (∂ϕ(str)/∂z) derived in the present work, it is found that the effect of ζ and that of b on Q(eof) and (∂ϕ(str)/∂z) can be separated from each other by varying the bulk ionic concentration. Thus, the slip coefficient as well as the zeta potential of hydrophobic microchannels can be found with reasonable accuracy by means of a nonlinear curve fitting method using measured data of Q(eof) and (∂ϕ(str)/∂z) at various bulk ionic concentrations. The present method allows an accurate estimation of slip coefficient of hydrophobic microchannels, which is quite simple and cheap compared with methods employing microparticle velocimetry. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tunable hydrodynamic characteristics in microchannels with biomimetic superhydrophobic (lotus leaf replica) walls.

Science.gov (United States)

Dey, Ranabir; Raj M, Kiran; Bhandaru, Nandini; Mukherjee, Rabibrata; Chakraborty, Suman

2014-05-21

The present work comprehensively addresses the hydrodynamic characteristics through microchannels with lotus leaf replica (exhibiting low adhesion and superhydrophobic properties) walls. The lotus leaf replica is fabricated following an efficient, two-step, soft-molding process and is then integrated with rectangular microchannels. The inherent biomimetic, superhydrophobic surface-liquid interfacial hydrodynamics, and the consequential bulk flow characteristics, are critically analyzed by the micro-particle image velocimetry technique. It is observed that the lotus leaf replica mediated microscale hydrodynamics comprise of two distinct flow regimes even within the low Reynolds number paradigm, unlike the commonly perceived solely apparent slip-stick dominated flows over superhydrophobic surfaces. While the first flow regime is characterized by an apparent slip-stick flow culminating in an enhanced bulk throughput rate, the second flow regime exhibits a complete breakdown of the aforementioned laminar and uni-axial flow model, leading to a predominantly no-slip flow. Interestingly, the critical flow condition dictating the transition between the two hydrodynamic regimes is intrinsically dependent on the micro-confinement effect. In this regard, an energetically consistent theoretical model is also proposed to predict the alterations in the critical flow condition with varying microchannel configurations, by addressing the underlying biomimetic surface-liquid interfacial conditions. Hence, the present research endeavour provides a new design-guiding paradigm for developing multi-functional microfluidic devices involving biomimetic, superhydrophobic surfaces, by judicious exploitation of the tunable hydrodynamic characteristics in the two regimes.

Evaporative CO$_2$ microchannel cooling for the LHCb VELO pixel upgrade

CERN Document Server

de Aguiar Francisco, Oscar A; Collins, Paula; Dumps, Raphael; John, Malcolm; Mapelli, Alessandro; Romagnoli, Giulia

2015-01-01

The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO$_2$ circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO$_2$, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO$_2$ cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use o...

A new miniature microchannel plate X-ray detector for synchrotron radiation

International Nuclear Information System (INIS)

Rosemeier, R.G.; Green, R.E. Jr.

1982-01-01

A state-of-the-art microchannel plate detector has been developed which allows real time X-ray imaging of X-ray diffraction as well as radiographic phenomenon. Advantages of the device include a 50 mm X-ray input, length less than 4'', and a weight of less than 1 lb. Since the use of synchrotron radiation is greatly facilitated by the capability of remote viewing of X-ray diffraction or radiographic images in real time, a prototype electro-optical system has been designed which couples the X-ray microchannel plate detector with a solid state television camera. Advantages of the miniature, lightweight, X-ray synchrotron camera include a large 50 mm X-ray input window, an output signal that is available in both analog format for display on a television monitor and in digital format for computer processing, and a completely modular design which allows all the components to be exchanged for other components optimally suited for the desired applications. (orig.)

Ferrofluid-in-oil two-phase flow patterns in a flow-focusing microchannel

Science.gov (United States)

Sheu, T. S.; Chen, Y. T.; Lih, F. L.; Miao, J. M.

This study investigates the two-phase flow formation process of water-based Fe3O4 ferrofluid (dispersed phase) in a silicon oil (continuous phase) flow in the microfluidic flow-focusing microchannel under various operational conditions. With transparent PDMS chip and optical microscope, four main two-phase flow patterns as droplet flow, slug flow, ring flow and churn flow are observed. The droplet shape, size, and formation mechanism were also investigated under different Ca numbers and intended to find out the empirical relations. The paper marks an original flow pattern map of the ferrofluid-in-oil flows in the microfluidic flow-focusing microchannels. The flow pattern transiting from droplet flow to slug flow appears for an operational conditions of QR < 1 and Lf / W < 1. The power law index that related Lf / W to QR was 0.36 in present device.

Dinâmica familiar: percepção de famílias de sobreviventes de câncer de mama Dinámica familiar: percepción de familias de sobrevivientes de cancer de mama Family dynamics: perceptions of breast cancer survivor's families

Directory of Open Access Journals (Sweden)

Raquel Gabrielli Biffi

2009-03-01

Full Text Available O estudo teve como objetivo identificar as percepções de familiares sobre a dinâmica de suas famílias após o câncer de mama em um dos seus membros. Estudo de abordagem qualitativa que tomou como referencial teórico o modelo de funcionamento familiar saudável proposto por Barnhill (1979. Participaram 23 familiares constituintes de 10 famílias. Os dados foram coletados, no período de maio a junho de 2002, por meio de entrevistas, e submetidos à análise de conteúdo. Os resultados revelaram aspectos positivos na dinâmica das famílias. A percepção dos processos de identidade, através da individuação e mutualidade, favoreceram a compreensão da dinâmica familiar. Os achados mostraram que o câncer de mama tem a capacidade de provocar alterações na família, e esta se utilizou dos potenciais de cada membro em particular na busca da estabilidade familiar.El estudio objetiva identificar las percepciones de familiares sobre la dinámica de sus familias, con cáncer de mama en uno de sus miembros. Estudio de abordaje cualitativo que tomó como referencial teórico el modelo de funcionamiento familiar saludable de Barnhill (1979. Participaron 23 familiares constituyentes de 10 familias. Los datos fueron obtenidos mediante entrevistas y sometidos a análisis de contenido. Los resultados revelaron aspectos positivos en la dinámica de las familias. La percepción de los procesos de identidad, a través de la individualización y mutualidad, favoreció la comprensión de la dinámica familiar. Según los resultados, el cáncer de mama tiene la capacidad de provocar alteraciones en la familia; por otro lado, éstas se utilizaron de los potenciales de cada miembro, en particular, en la búsqueda de la estabilidad familiar.The aim of this study was to identify the family members´ perceptions of their family dynamics, after breast cancer in one of its members. The study used a qualitative approach based on the theoretical model of healthy

3D tomography of cells in micro-channels

Science.gov (United States)

Quint, S.; Christ, A. F.; Guckenberger, A.; Himbert, S.; Kaestner, L.; Gekle, S.; Wagner, C.

2017-09-01

We combine confocal imaging, microfluidics, and image analysis to record 3D-images of cells in flow. This enables us to recover the full 3D representation of several hundred living cells per minute. Whereas 3D confocal imaging has thus far been limited to steady specimens, we overcome this restriction and present a method to access the 3D shape of moving objects. The key of our principle is a tilted arrangement of the micro-channel with respect to the focal plane of the microscope. This forces cells to traverse the focal plane in an inclined manner. As a consequence, individual layers of passing cells are recorded, which can then be assembled to obtain the volumetric representation. The full 3D information allows for a detailed comparison with theoretical and numerical predictions unfeasible with, e.g., 2D imaging. Our technique is exemplified by studying flowing red blood cells in a micro-channel reflecting the conditions prevailing in the microvasculature. We observe two very different types of shapes: "croissants" and "slippers." Additionally, we perform 3D numerical simulations of our experiment to confirm the observations. Since 3D confocal imaging of cells in flow has not yet been realized, we see high potential in the field of flow cytometry where cell classification thus far mostly relies on 1D scattering and fluorescence signals.

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications

Energy Technology Data Exchange (ETDEWEB)

Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

2008-01-01

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Conhecimento das mulheres sobre o autoexame de mamas na atenção básica Conocimiento de las mujeres sobre el autoexamen de mamas en la atención Basic Women´s basic knowledge about breast self-examination

Directory of Open Access Journals (Sweden)

Verbena Santos Araújo

2010-12-01

Full Text Available O câncer de mama é um dos graves problemas de saúde pública pela sua alta incidência, importância epidemiologia e magnitude social. Este trabalho investigou o conhecimento das mulheres acerca do autoexame, através da detecção daquelas que o fazem e a sua periodicidade. Tratou-se de um estudo quantitativo, realizado na Estratégia Saúde da Família Pedreira I, em Campina Grande/PB. Direcionou-se às mulheres entre 30 e 39 anos, utilizando-se uma amostra de 20% do total de mulheres cadastradas na referida unidade. O material empírico foi obtido através de questionário, o qual foi submetido a uma análise temática e estatística. Os resultados apontaram que 94,59% das entrevistadas conhecem o câncer de mama, 83,7% relataram saber como se prevenir, 67% afirmaram realizar o autoexame, das quais apenas 16 % o fazem regularmente. Após a análise dos dados, observou-se que a maioria das mulheres ainda apresenta dúvidas em relação ao período de realização do autoexame, daí a importância de se fazer uma prevenção adequada. É primordial investir em políticas de saúde pública que informem e incentivem a prática do autocuidado, no período adequado, objetivando a prevenção e, consequentemente, a diminuição dos dados estatísticos notificados de câncer de mama.El cáncer de mama es uno de los graves problemas de salud pública dada su alta incidencia, importancia epidemiológica y magnitud social. Este trabajo investigó el conocimiento de las mujeres acerca del autoexamen, mediante la detección de aquellas que lo hacen y su periodicidad. Se trató de un estudio cuantitativo, realizado en la Estrategia de Salud de la Familia Pedreira I, en Campina Grande, Paraíba. Se orientó hacia mujeres entre 30 y 39 años, utilizando una muestra de 20% del total de las mujeres registradas en la referida unidad. El material empírico fue obtenido a través de un cuestionario, el cual fue sometido a análisis temático y estad

Next Generation Microchannel Heat Exchangers

CERN Document Server

Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin

2013-01-01

In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

Hipertrofia Maciça das Mamas na Gravidez: Relato de Caso Massive Hypertrophy of the Breasts in Pregnancy: A Case Report

Directory of Open Access Journals (Sweden)

Amadeu Ramos da Silva Filho

2002-07-01

Full Text Available A hipertrofia maciça das mamas na gestação é uma situação rara, com poucos casos descritos na literatura. Apesar de a etiologia ser desconhecida, parece tratar-se de resposta exagerada dos receptores da mama aos hormônios gravídicos. Embora possa ocorrer em qualquer gravidez apresenta alta taxa de recorrência nas gestações subseqüentes. O rápido e descomunal aumento mamário determina, além da dor, o comprometimento do esqueleto e musculatura das espáduas. O excessivo crescimento pode provocar necrose da pele com formação de úlceras, favorecendo grave infecção das glândulas. Os autores relatam um caso ocorrido em secundigesta, expondo a conduta durante a gravidez e a inibição da lactação com uso da bromocriptina imediatamente após o parto, com enfaixamento das mamas elevadas. Realçam também a importância da mamoplastia redutora poucos meses após o parto.Massive hypertrophy of the breast in pregnancy is a rare condition, with few cases reported. In spite of the unknown etiology, it seems to be an exaggerated response of the breast receptors to the pregnancy hormones. Although it can happen in any pregnancy, it presents great capacity to recur in all subsequent pregnancies. The rapid and colossal breast enlargement determines pain and the involvement of the shoulder skeleton and muscles. The excessive enlargement may promote necrosis and ulceration of the skin, leading to breast infection. The authors report one case at the second pregnancy, explaining management during the pregnancy, lactation inhibition with bromocriptine immediately after the delivery and the banding of the elevated breast. They also emphasize the importance of reduction mammoplasty a few months after delivery.

High density gold nanoparticles immobilized on surface via plasma deposited APTES film for decomposing organic compounds in microchannels

Science.gov (United States)

Rao, Xi; Guyon, Cédric; Ognier, Stephanie; Da Silva, Bradley; Chu, Chenglin; Tatoulian, Michaël; Hassan, Ali Abou

2018-05-01

Immobilization of colloidal particles (e.g. gold nanoparticles (AuNps)) on the inner surface of micro-/nano- channels has received a great interest for catalysis. A novel catalytic ozonation setup using a gold-immobilized microchannel reactor was developed in this work. To anchor AuNps, (3-aminopropyl) triethoxysilane (APTES) with functional amine groups was deposited using plasma enhanced chemical vapor deposition (PECVD) process. The results clearly evidenced that PECVD processing exhibited relatively high efficiency for grafting amine groups and further immobilizing AuNPs. The catalytic activity of gold immobilized microchannel was evaluated by pyruvic acid ozonation. The decomposition rate calculated from High Performance Liquid Chromatography (HPLC) indicated a much better catalytic performance of gold in microchannel than that in batch. The results confirmed immobilizing gold nanoparticles on plasma deposited APTES for preparing catalytic microreactors is promising for the wastewater treatment in the future.

Recursos disponibles para el tratamiento del cáncer de mama en México Available resources for the treatment of breast cancer in Mexico

Directory of Open Access Journals (Sweden)

Alejandro Mohar

2009-01-01

Full Text Available OBJETIVO: Describir los recursos existentes para el tratamiento del cáncer de mama en México. MATERIAL Y MÉTODOS: Se recolectó información de 23 Centros Estatales de Cáncer (CEC, dos hospitales federales y el Instituto Nacional de Cancerología. Este estudio se realizo en México, DF, en agosto y septiembre del año 2008. RESULTADOS: Los 23 CEC ofrecen atención médica para el cáncer de mama, incluidos cirugía, quimioterapia y radioterapia, todos ellos acreditados por el Seguro Popular. Las cuotas de recuperación se definieron por etapa clínica, desde 27 500 pesos para la etapa clínica cero hasta 480 000 pesos en pacientes con enfermedad avanzada. Se ha atendido a 2 689 pacientes con cáncer de mama; sólo 1% se presentó con carcinoma in situ CONCLUSIONES: Se tiene la infraestructura y los recursos médicos para el óptimo tratamiento, pero los costos son altos debido al diagnóstico tardío. La detección oportuna del cáncer de mama es una prioridad para el óptimo control de esta enfermedad en México.OBJECTIVE: Describe the resources for the treatment of breast cancer in Mexico. METHODS: Information was obtained from 23 Centros Estatales de Cáncer (State Cancer Centers, CEC, two federal hospitals and Cancerología. This study was performed in Mexico City in August/September of 2008. RESULTS: These 23 centers provide medical care for breast cancer including surgery, chemotherapy and radiotherapy; all of them validated by the Seguro Popular. The costs were defined according to clinical stage and ranged from $27,500.00 pesos for clinical stage 0 to $480,00.00 in the advanced stage. A total of 2 689 women with breast cancer have been treated; only 1% was reported with in situ carcinoma. CONCLUSIONS: An adequate medical infrastructure is in place to treat breast cancer in Mexico. The costs are high due to late diagnosis of the disease. Early detection of breast cancer is a high priority for optimal control of this disease in Mexico.

Mortalidade e assistência oncológica no Rio de Janeiro: câncer de mama e colo uterino Mortality and care oncology in Rio de Janeiro: cancer of the breast and cervix of uterus

Directory of Open Access Journals (Sweden)

Raíla de Souza Santos

2011-06-01

Full Text Available O município do Rio de Janeiro apresenta grandes taxas de mortalidade para o câncer de mama e colo uterino. Analisou-se a trajetória dos óbitos por câncer de mama e colo uterino no município do Rio de Janeiro e relacionaram-se a oferta de serviços de saúde e o fluxo de pacientes entre o local de residência e o hospital. Estudo ecológico de base populacional que analisou óbitos por câncer de mama e colo uterino no município do Rio de Janeiro, no período de 2005-2008, mapeando os fluxos de casos da residência para os serviços de saúde. O Sistema de Informação sobre Mortalidade registrou, no período analisado, 3.384 óbitos por câncer de mama e 771 óbitos por câncer do colo de útero. A localização geográfica dos estabelecimentos de saúde define uma distribuição espacial dos óbitos extremamente desigual, alternando padrões de escassez em algumas áreas (periferia da cidade e excesso em outras (Centro.La ciudad de Rio de Janeiro tiene altas tasas de mortalidad por cáncer de mama y cuello uterino. Se analizó la trayectoria de las muertes por cáncer de mama y cáncer cervico-uterino en Rio de Janeiro y se vinculó la prestación de servicios de salud y el flujo de pacientes entre la residencia y el hospital. Estudio ecológico basado en la población que examinó las muertes de cáncer de mama y el cáncer cervical en la ciudad de Rio de Janeiro, en el período 2005-2008. El Sistema de Información sobre la mortalidad ha registrado en el período analizado 3.384 muertes por cáncer de mama y 771 muertes por cáncer de cáncer de cuello uterino. La ubicación geográfica de los centros de salud definió una distribución espacial de las muertes extremadamente desigual, alternando los padrones de escasez en algunas zonas (fuera de la ciudad y el exceso en los demás (Central.The city of Rio de Janeiro has high rates of mortality for breast cancer and uterine cervix. In this study was analyzed the trajectory of deaths

Shock wave attenuation in a micro-channel

Science.gov (United States)

Giordano, J.; Perrier, P.; Meister, L.; Brouillette, M.

2018-05-01

This work presents optical measurements of shock wave attenuation in a glass micro-channel. This transparent facility, with a cross section ranging from 1 mm× 150 μm to 1 mm× 500 μm, allowed for the use of high-speed schlieren videography to visualize the propagation of a shock wave within the entire micro-channel and to quantify velocity attenuation of the wave due to wall effects. In this paper, we present the experimental technique and the relevant data treatment we have used to increase the sensitivity of shock wave detection. Then, we compared our experimental results for different channel widths, lengths, and shock wave velocities with the analytical model for shock attenuation proposed by Russell (J Fluid Mech 27(2):305-314, 1967), which assumes laminar flow, and by Mirels (Attenuation in a shock tube due to unsteady-boundary-layer action, NACA Report 1333, 1957) for turbulent flow. We found that these models are inadequate to predict the observed data, owing to the presence of fully developed flow which violates the basic assumption of these models. The data are also compared with the empirical shock attenuation models proposed by Zeitoun (Phys Fluids 27(1):011701, 2015) and Deshpande and Puranik (Shock Waves 26(4):465-475, 2016), where better agreement is observed. Finally, we presented experimental data for the flow field behind the shock wave from measurements of the Mach wave angle which shows globally decreasing flow Mach numbers due to viscous wall effects.

Developing the laminar MHD forced convection flow of water/FMWNT carbon nanotubes in a microchannel imposed the uniform heat flux

Energy Technology Data Exchange (ETDEWEB)

Karimipour, Arash; Taghipour, Abdolmajid [Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Malvandi, Amir, E-mail: amirmalvandi@aut.ac.ir [Department of Mechanical Engineering, Neyshabur Branch, Islamic Azad University, Neyshabur (Iran, Islamic Republic of)

2016-12-01

This paper aims to investigate magnetic field and slip effects on developing laminar forced convection of nanofluids in the microchannels. A novel mixture of water and FMWNT carbon nanotubes is used as the working fluid. To do this, fluid flow and heat transfer through a microchannel is simulated by a computer code in FORTRAN language. The mixture of FMWNT carbon nanotubes suspended in water is considered as the nanofluid. Slip velocity is supposed as the hydrodynamic boundary condition while the microchannel's lower wall is insulated and the top wall is under the effect of a constant heat flux. Moreover, the flow field is subjected to a magnetic field with a constant strength. The results are presented as the velocity, temperature and Nusselt number profiles. It is observed that nanofluid composed of water and carbon nanotubes (FMWNT) can work well to increase the heat transfer rate along the microchannel walls. Furthermore, it is indicated that imposing the magnetic field is very effective at the thermally developing region. In contrast, the magnetic field effect at fully developed region is insignificant, especially at low values of Reynolds number. - Highlights: • Simulation of water/FMWNT carbon nanotubes flow in a microchannel. • The effects of magnetic field strength on nanofluid's slip velocity. • The effects of Ha, Re, ϕ and slip coefficient on averaged Nusselt number. • Magnetic field effect at developing flow region is significant.

Fast microchannel plate detector for particles

International Nuclear Information System (INIS)

Wurz, P.; Gubler, L.

1996-01-01

In this article we report on the timing capabilities of a new microchannel plate detector we designed and built. The detector assembly has an impedance-matched transition line (50 Ω line resistance) from anode to cable connector which is considerably smaller than other, commercially available solutions and at the same time has about four times the active area. The detector was tested with an alpha particle source and excellent time response was achieved. Using 10 μm pore size channel plates, a rise time of 300 ps and a pulse width of 520 ps are obtained. The details of the signal analysis are also given in the article. copyright 1996 American Institute of Physics

Investigating performance of microchannel evaporators for automobile air conditioning with different port structures

Directory of Open Access Journals (Sweden)

Guoliang Zhou

2017-08-01

Full Text Available Microchannel evaporator has been widely applied in automobile air conditioning, while it faces the problem of refrigerant maldistribution which deteriorates the thermal performance of evaporator. In this study, the performances of microchannel evaporators with different port structures are experimentally investigated for purpose of reducing evaporator pressure drop. Four evaporator samples with different port number and hydraulic diameter are made for this study. The performances of the evaporator samples are tested on a psychometric calorimeter test bench with the refrigerant R-134A at a real automobile air conditioning. The results on the variations of the evaporator pressure drop and evaporator surface temperature distribution are presented and analyzed. By studying the performance of an evaporator, seeking proper port structure is an approach to reduce refrigerant pressure drop as well as improve refrigerant distribution.

Activity and lifetime of urease immobilized using layer-by-layer nano self-assembly on silicon microchannels.

Science.gov (United States)

Forrest, Scott R; Elmore, Bill B; Palmer, James D

2005-01-01

Urease has been immobilized and layered onto the walls of manufactured silicon microchannels. Enzyme immobilization was performed using layer-by-layer nano self-assembly. Alternating layers of oppositely charged polyelectrolytes, with enzyme layers "encased" between them, were deposited onto the walls of the silicon microchannels. The polycations used were polyethylenimine (PEI), polydiallyldimethylammonium (PDDA), and polyallylamine (PAH). The polyanions used were polystyrenesulfonate (PSS) and polyvinylsulfate (PVS). The activity of the immobilized enzyme was tested by pumping a 1 g/L urea solution through the microchannels at various flow rates. Effluent concentration was measured using an ultraviolet/visible spectrometer by monitoring the absorbance of a pH sensitive dye. The architecture of PEI/PSS/PEI/urease/PEI with single and multiple layers of enzyme demonstrated superior performance over the PDDA and PAH architectures. The precursor layer of PEI/PSS demonstrably improved the performance of the reactor. Conversion rates of 70% were achieved at a residence time of 26 s, on d 1 of operation, and >50% at 51 s, on d 15 with a six-layer PEI/urease architecture.

Câncer de mama e sofrimento psicológico: aspectos relacionados ao feminino El cáncer de mama y el sufrimiento psicológico: aspectos relacionados con el femenino Breast cancer and psychological suffering: female-related aspects

Directory of Open Access Journals (Sweden)

Lucia Cecilia da Silva

2008-06-01

Full Text Available No Brasil e no mundo a incidência do câncer de mama vem aumentando e aparecendo cada vez mais cedo na vida da mulher. O tratamento envolve mastectomia, quimioterapia e radioterapia, que, pelos seus efeitos físicos, podem comprometer em variados graus a auto-estima, a imagem corporal e a identidade feminina daquelas que recebem o diagnóstico da doença. Além disso, em nossa sociedade o câncer adquiriu significados relacionados a culpa, punição, deterioração, dor e morte, agravando o sofrimento psicológico das doentes. Neste sentido, este artigo tem o objetivo de levantar alguns pontos de reflexão no que se relaciona aos significados culturais da doença e do significado do seio enquanto ícone da identidade feminina. Partimos do princípio de que enriquecer a compreensão dos aspectos que influenciam o sofrimento da mulher com câncer de mama contribui para que os profissionais de saúde, principalmente os de saúde mental, possam assisti-la de maneira mais eficiente e abrangente.En Brasil y en el mundo la incidencia del cáncer de mama está en acenso. Es una enfermedad que está manifestándose cada vez más temprano en la vida de la mujer. El tratamiento envuelve mastectomía, quimioterapia y radioterapia que, por sus efectos físicos, pueden comprometer en variados grados la autoestima, la imagen corporal y la identidad femenina de aquellas mujeres que reciben el diagnóstico de la enfermedad. Además de eso, en nuestra sociedad el cáncer ha adquirido significados relacionados con la culpa, punición, deterioración, dolor y muerte, agravando el sufrimiento psicológico de las enfermas. En este sentido, este artículo tiene como objetivo levantar algunos puntos de reflexión en lo que se relaciona con los significados culturales de la enfermedad y del significado del seno como icono de la identidad femenina. Partimos del supuesto de que enriquecer la comprensión de los aspectos que pueden influenciar el sufrimiento de la mujer

Padrão alimentar de mulheres com câncer de mama: um estudo a posteriori

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Karin Sedó Sarkis

2014-09-01

Full Text Available Objetivo: Identificar o padrão alimentar a posteriori de mulheres com câncer de mama. Métodos: Estudo observacional, transversal e analítico. Foram avaliadas 100 mulheres com câncer de mama submetidas à quimioterapia / radioterapia, atendidas em um centro de câncer na cidade de Fortaleza, de Julho-Dezembro de 2012. Os dados clínicos, socioeconômicos e antropométricos foram analisados. Para avaliação do consumo foi utilizado um QFA validado, e o consumo diário de cada alimento foi definido em gramas. Então eles foram agrupados de acordo com sua composição nutricional, seguindo a pirâmide alimentar adaptada à população brasileira, em 10 grupos de alimentos. Resultados: Idade média 50,9 anos, com prevalência de carcinoma ductal (83% em estágio III (60%. A média do IMC indica excesso de peso (28,3 kg/m2 e a circunferência da cintura estava acima do recomendado (98,6 cm. Nós identificamos quatro componentes alimentares e 21% da variância da dieta foi explicado pelo componente alimentar 1 (Risk, com a matriz composta por carne vermelha e processada, óleos e gorduras e cereais. Conclusão: O padrão alimentar das pacientes foi caracterizado por uma dieta de risco.

TUMOR PHYLLODES DE LA MAMA.CARACTERIZACIÓN EN LA PROVINCIA CIENFUEGOS.ESTUDIO DE 20 AÑOS

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Lidia Torres Aja

2007-01-01

Full Text Available El tumor Phyllodes de la mama es poco frecuente. Tiene un origen fibroepitelial con potencial agresivo y representa el 0.3% a 0.4% de todos los tumores mamarios y el 2.5% a 3% de los tumores epiteliales de dicho órgano.Objetivo: Nuestro objetivo fundamental es caracterizar desde el punto de vista clínico patológico los tumores Phyllodes operados en la provincia de Cienfuegos durante 20 años.Tipo de estudio: descriptivo prospectivo observacional. Periodo evaluado: 20 años desde 1 de enero de 1987 hasta el 31 de diciembre del 2006. Universo: 57 pacientes.Métodos: para realizar nuestra investigación hemos seguido anualmente durante estos 20 años los casos operados en nuestra provincia, examinando personalmente los casos en consulta de Mastología antes de operarlos y siguiéndolo por consulta de operados durante más de 5 añosResultados fundamentales: como resultados fundamentales de nuestra investigación obtuvimos que se operaron en esos 20 años un total de 57 tumores Phyllodes, los cuales representaron el 2.9% del total de tumores fibroepiteliales de mama operados.Aunque el mayor número de casos se detectó en pacientes de más de 40 años, queremos resaltar que en este periodo se operaron los únicos tumores Phyllodes en niña y en adolescente reportados en nuestra provincia

Factores pronósticos del Cáncer de Mama en servicio de Oncología del Hospital General Camilo Cienfuegos. Enero 2007–2012

Directory of Open Access Journals (Sweden)

Yania Luisa Jiménez Madrigal

2015-09-01

Full Text Available Se analizaron 200 pacientes con diagnóstico de cáncer de mama, en un período de 5 años (Enero 2007 a Enero 2012 que fueron diagnosticados y tratados en la consulta especializada de mama en el Servicio de Oncología del Hospital Universitario de Sancti-Spíritus. Se estudiaron los factores pronósticos relacionados con el tumor primario, la presencia de ganglios metastásico, el tratamiento efectuado, el tiempo libre de enfermedad y el tiempo de sobrevida. Se comprobó en nuestra serie el predominio de pacientes con 60 años y más, con localización más frecuente en la mama izquierda, y el cuadrante superior-externo fue el sitio mamario más afectado. Los factores pronóstico significativos y de mayor relevancia en cuanto al tiempo libre de enfermedad y tiempo de sobrevida fueron: tamaño tumoral, status ganglionar, infiltración periganglionar y la determinación de la hormono dependencia. Se demostró que en la medida que aumenta el tamaño del tumor primario (T y la afectación ganglionar regional (N, la etapa clínica sea más avanzada y los ganglios axilares en la pieza quirúrgica metastásicos condicionan que exista mayor posibilidad de que ocurra recurrencia tumoral, con una incidencia mayor a presentar metástasis a distancia y que ocurra la muerte en estas pacientes.

Câncer de Mama Associado à Gravidez: Um Estudo Caso/Controle Breast Cancer Associated With Pregnancy: A Case Control Study

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Juvenal Mottola Junior

2002-10-01

Full Text Available Objetivo:relatar série de 15 casos de câncer de mama associado à gravidez e comparar com um grupo controle de pacientes jovens com carcinoma ductal invasivo da mama, avaliando o estadiamento clínico, o comprometimento linfonodal axilar, o grau nuclear, o grau histológico e os receptores hormonais de estrógeno e progesterona. Métodos: foi realizado estudo retrospectivo de 15 casos de pacientes com câncer de mama associado à gravidez, atendidas no setor de Mastologia do Centro de Referência da Saúde da Mulher, Hospital Pérola Byington, em São Paulo, durante o período de setembro de 1996 a abril de 2001, designando como base principal do estudo a avaliação do estadiamento clínico, a época do diagnóstico e o comprometimento axilar. Também, foram analisados a faixa etária, paridade, tipo histológico, tratamento realizado, características histológicas quanto ao grau nuclear e grau histológico, e a presença de receptores hormonais nos tumores diagnosticados. Comparou-se este grupo com um grupo controle de pacientes jovens com câncer de mama. Resultados: verificou-se que 7 pacientes com câncer de mama associado à gravidez (46,7% encontravam-se com doença localmente avançada (estádio clínico IIIA e IIIB e 3 pacientes (20% apresentavam doença disseminada no momento do diagnóstico. As pacientes apresentaram em média 2,4 linfonodos axilares comprometidos, sendo que apenas uma paciente (6,6% não apresentava comprometimento linfonodal axilar. Com relação à época do diagnóstico, 40% dos cânceres foram diagnosticados durante a lactação, 46,7% durante o terceiro trimestre e 13,3% no segundo trimestre. Comparou-se este grupo de pacientes grávidas com um grupo controle de pacientes, com a mesma média etária, não grávidas, portadoras de carcinoma invasivo de mama analisando o estadiamento clínico, o comprometimento linfonodal axilar, grau nuclear, grau histológico e os receptores hormonais de estrógeno e

Usurpación simbólica: identidad y poder en la fiesta de la Mama Negra

OpenAIRE

Guerrero Arias, Patricio

2002-01-01

La presente tesis aborda el proceso al que hemos denominado de usurpación simbólica, mediante el cual los sectores dominantes locales de la ciudad de Latacunga, han usurpado los símbolos de la fiesta de la Mama Negra que se celebra como un acto de religiosidad popular por parte de los sectores subalternos en el mes de septiembre, para transformar su sentido y convertirla en un acto ritual político a través del cual se hace posible la legitimación del poder y su ejercicio. Es...

Modeling of low-capillary number segmented flows in microchannels using OpenFOAM

NARCIS (Netherlands)

Hoang, D.A.; Van Steijn, V.; Portela, L.M.; Kreutzer, M.T.; Kleijn, C.R.

2012-01-01

Modeling of low-Capillary number segmented flows in microchannels is important for the design of microfluidic devices. We present numerical validations of microfluidic flow simulations using the volume-of-fluid (VOF) method as implemented in OpenFOAM. Two benchmark cases were investigated to ensure

Direct fabrication of polymer micro-lens array

Science.gov (United States)

Coppola, S.; Pagliarulo, V.; Vespini, V.; Nasti, G.; Olivieri, F.; Grilli, S.; Ferraro, P.

2017-06-01

In order to break the rigidity of classic lithographic techniques, a flexible pyro-electric-electrohydrodynamic (EHD) inkjet printing is presented. In particular, here is showed a method able to manipulate highly viscous polymers, usable for optical integrated devices. The system proposed reaches spatial resolution up to the nano-scale and can print, for instance, nano-particles and high viscous polymer solutions. This technique allows writing patterns directly onto a substrate of interest in 2D or in 3D configuration and is studied in order to overcome limitations in terms of type of materials, geometry and thickness of the substrate. In the present work, we show the potential of pyro-EHD printing in fields as optics and micro-fluidics. A micro-channel chip is functionalized with a PDMS-made micro-lenses array, directly printed on the chip. The geometric properties and the quality of the lenses are evaluated by a Digital Holography (DH) analysis.

Cáncer de mama en México: una prioridad apremiante Breast cancer in Mexico: an urgent priority

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Felicia Marie Knaul

2009-01-01

Full Text Available El cáncer de mama es una grave amenaza para la salud de la mujer a nivel mundial y constituye una prioridad no reconocida en los países de ingresos medios. Este trabajo presenta datos de México y revela que desde 2006 el cáncer de mama es causante de un mayor número de muertes que el cáncer cérvicouterino. Esta afección es la segunda causa de muerte en mujeres de 30 a 54 años de edad y amenaza a todos los grupos socioeconómicos. Los datos sobre detección, si bien subreportados, muestran 6000 nuevos casos en 1990 y se estima un incremento cercano a 16500 nuevos casos anuales para 2020. Más aún, la mayoría de los casos se autodetecta y sólo 10% de todos los casos se identifica en etapa I. La seguridad social en México cubre alrededor de 40 a 45% de la población e incluye tratamiento del cáncer de mama. A partir de 2007, la población sin seguridad social tiene derecho a tratamiento de cáncer de mama a través del Seguro Popular de Salud. A pesar de esto, los servicios escasean y las intervenciones de detección temprana, en particular la mamografía, son muy limitadas. Desde el año 2006, sólo 22% de las mujeres de 40 a 69 años se sometió a una mamografía en el último año. Existen barreras tanto en la demanda como en la oferta. El cabildeo, la educación, la creación de conciencia y una respuesta articulada de políticas son importantes para garantizar una mayor cobertura, acceso y aceptación tanto del tratamiento como de la detección temprana.Breast cancer is a serious threat to the health of women globally and an unrecognized priority in middle-income countries. This paper presents data from Mexico. It shows that breast cancer accounts for more deaths than cervical cancer since 2006. It is the second cause of death among women aged 30 to 54 and affects all socioeconomic groups. Data on detection, although underreported, show 6000 new cases in 1990 and a projected increase to over 16500 per year by 2020. Further, the

Hydrogen production through aqueous-phase reforming of ethylene glycol in a washcoated microchannel

NARCIS (Netherlands)

Neira d'Angelo, M.F.; Ordomskiy, V.; Paunovic, V.; Schaaf, van der J.; Schouten, J.C.; Nijhuis, T.A.

2013-01-01

Aqueous-phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. Single microchannel experiments are conducted following a simplified model based on the microreactor concept. A coating

Technology Development of an Advanced Small-scale Microchannel-type Process Heat Exchanger (PHE) for Hydrogen Production in Iodine-sulfur Cycle

Energy Technology Data Exchange (ETDEWEB)

Sah, Injin; Kim, Chan Soo; Kim, Yong Wan; Park, Jae-Won; Kim, Eung-Seon; Kim, Min-Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

In this study, ongoing manufacturing processes of the components employed in an advanced small-scale microchannel-type PHE are presented. The components, such as mechanically machined microchannels and a diffusion-bonded stack are introduced. Also, preliminary studies on surface treatment techniques for improving corrosion resistance from the corrosive sulfuric environment will be covered. Ongoing manufacturing process for an advanced small-size microchannel-type PHE in KAERI is presented. Through the preliminary studies for optimizing diffusion bonding condition of Hastelloy-X, a diffusion-bonded stack, consisting of primary and secondary side layer by layer, is scheduled to be fabricated in a few months. Also, surface treatment for enhancing the corrosion resistance from the sulfuric acid environment is in progress for the plates with microchannels. A massive production of hydrogen with electricity generation is expected in a Process Heat Exchanger (PHE) in a Very High Temperature gas-cooled Reactor (VHTR) system. For the application of hydrogen production, a small-scale gas loop for feasibility testing of a laboratory-scale has constructed and operated in Korea Atomic Energy Research Institute (KAERI) as a precursor to an experimental- and a pilot-scale gas loops.

Modelling and Pareto optimization of heat transfer and flow coefficients in microchannels using GMDH type neural networks and genetic algorithms

International Nuclear Information System (INIS)

Amanifard, N.; Nariman-Zadeh, N.; Borji, M.; Khalkhali, A.; Habibdoust, A.

2008-01-01

Three-dimensional heat transfer characteristics and pressure drop of water flow in a set of rectangular microchannels are numerically investigated using Fluent and compared with those of experimental results. Two metamodels based on the evolved group method of data handling (GMDH) type neural networks are then obtained for modelling of both pressure drop (ΔP) and Nusselt number (Nu) with respect to design variables such as geometrical parameters of microchannels, the amount of heat flux and the Reynolds number. Using such obtained polynomial neural networks, multi-objective genetic algorithms (GAs) (non-dominated sorting genetic algorithm, NSGA-II) with a new diversity preserving mechanism is then used for Pareto based optimization of microchannels considering two conflicting objectives such as (ΔP) and (Nu). It is shown that some interesting and important relationships as useful optimal design principles involved in the performance of microchannels can be discovered by Pareto based multi-objective optimization of the obtained polynomial metamodels representing their heat transfer and flow characteristics. Such important optimal principles would not have been obtained without the use of both GMDH type neural network modelling and the Pareto optimization approach

Conhecimentos dos acadêmicos sobre prevenção do câncer de mama Conocimiento de los estudiantes sobre la prevención del cáncer de mama Undergraduate students' knowledge about the prevention of breast cancer

Directory of Open Access Journals (Sweden)

Catia Regina Pirhardt Freitas

2011-12-01

Full Text Available Estudo com o objetivo de identificar o conhecimento dos acadêmicos, quanto aos fatores de prevenção para o câncer de mama. De natureza quantitativa, exploratória e descritiva, desenvolvido numa instituição de ensino superior do Estado de Santa Catarina, com 50 acadêmicos matriculados nos cursos de enfermagem, fisioterapia e psicologia no 1º semestre de 2008. A coleta de dados ocorreu de fevereiro a abril de 2008. Utilizou-se um questionário semi-estruturado e análise estatística descritiva. Os resultados apontaram que os acadêmicos dos cursos de enfermagem e fisioterapia demonstraram maior conhecimento sobre o tema. Os fatores de prevenção mencionados foram: consumo de legumes, verduras, frutas, exercícios físicos e amamentação. Conclui-se que o nível de conhecimento dos estudantes sobre os fatores de prevenção do câncer de mama, numa perspectiva interdisciplinar, é importante para repensar a inserção da educação em saúde como conteúdo curricular imprescindível na promoção de uma universidade saudável.Objetivo del estudio fue identificar el conocimiento de los estudiantes, acerca de los factores para la prevención del cáncer de mama. Un cuantitativo exploratorio y descriptivo, desarrollado en una institución de educación superior de Santa Catarina, Brasil, con 50 estudiantes matriculados en la enfermería, fisioterapia y psicología en el primer semestre de 2008. Los datos fueron recolectados de febrero a abril de 2008. Se utilizó un cuestionario semi-estructurado y estadística descriptiva. Los resultados mostraron que los estudiantes de enfermería y terapia física han demostrado mayor conocimiento sobre el tema que los estudiantes de psicología. Menciona factores: el consumo de verduras, frutas, el ejercicio físico y la lactancia. Se concluye que el nivel de conocimiento acerca de los factores que pueden prevenir el cáncer de mama, una perspectiva interdisciplinaria, es importante para reconsiderar

A SEXUALIDADE DA MULHER COM CÂNCER DE MAMA: ANÁLISE DA PRODUÇÃO CIENTÍFICA DE ENFERMAGEM

Directory of Open Access Journals (Sweden)

Simone Mara de Araújo Ferreira

2013-01-01

Full Text Available Revisión integrativa que tuvo por como objetivo analizar el conocimiento producido por la enfermería brasileña sobre la sexualidad de mujeres con cáncer de mama, con la finalidad de obtener subsidios para ofrecer una asistencia de calidad. Fue utilizada una busca simultánea por palabras, en todas las bases de datos indexadas en la BVS. Se incluyeron 10 artículos publicados a partir del año 2000, en cuya autoría constaban enfermeros. Los resultados mostraron que la sexualidad de las mujeres muchas veces está restricta a la práctica sexual y apenas unos relatos muestran la sexualidad como algo más integral. Las mujeres afectadas por cáncer de mama presentan dificultad en el ejercicio de la sexualidad y el apoyo del compañero ayuda a hacer ese enfrentamiento, siendo percibido como de extrema significancia en todas las etapas de la enfermedad. El análisis de los resultados evidencia una asistencia de Enfermería que no contempla este aspecto del cuidado, evidenciándose las necesidad de una reestructuración. Esa asistencia debe ser extendida a los compañeros y debe ultrapasar la dimensión biológica.

Effects of microchannel confinement on acoustic vaporisation of ultrasound phase change contrast agents

Science.gov (United States)

Lin, Shengtao; Zhang, Ge; Hau Leow, Chee; Tang, Meng-Xing

2017-09-01

The sub-micron phase change contrast agent (PCCA) composed of a perfluorocarbon liquid core can be activated into gaseous state and form stable echogenic microbubbles for contrast-enhanced ultrasound imaging. It has shown great promise in imaging microvasculature, tumour microenvironment, and cancer cells. Although PCCAs have been extensively studied for different diagnostic and therapeutic applications, the effect of biologically geometrical confinement on the acoustic vaporisation of PCCAs is still not clear. We have investigated the difference in PCCA-produced ultrasound contrast enhancement after acoustic activation with and without a microvessel confinement on a microchannel phantom. The experimental results indicated more than one-order of magnitude less acoustic vaporisation in a microchannel than that in a free environment taking into account the attenuation effect of the vessel on the microbubble scattering. This may provide an improved understanding in the applications of PCCAs in vivo.

Experimental and numerical investigations of ionic liquid-aqueous flow in microchannel

Science.gov (United States)

Li, Qi; Tsaoulidis, Dimitrios; Angeli, Panagiota

2015-11-01

The hydrodynamic characteristics of plug flow of an ionic liquid-aqueous two-phase system in a microchannel were studied experimentally and numerically. A mixture of 0.2M N-octyl(plenyl)-N,N-diisobutylcarbamoylmethyphosphine oxide (CMOP)- 1.2 M Tri-n-butylphosphate (TBP) in room temperature ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide ([C4min][NTf2]), and a nitric acid solution of 1M were chosen. These fluids are relevant Eu(III) separation by extraction from nitric acid solutions. The two liquid phases were introduced into microchannels of 0.2 and 0.5mm internal diameter through a T-junction inlet. The flow pattern was visualized during plug formation at the inlet section and further downstream by means by bright field planar micro-Particle Image Velocimetry. Key features of plug flow, such as plug velocity, film thickness, plug length and recirculation intensity were measured under various experimental conditions. To gain further understanding of the 3-D flow field, Computation Fluid Dynamics (CFD) simulations approach were also conducted.

Numerical simulation of electroosmotic flow in rough microchannels using the lattice Poisson-Nernst-Planck methods

Science.gov (United States)

Kamali, Reza; Soloklou, Mohsen Nasiri; Hadidi, Hooman

2018-05-01

In this study, coupled Lattice Boltzmann method is applied to solve the dynamic model for an electroosmotic flow and investigate the effects of roughness in a 2-D flat microchannel. In the present model, the Poisson equation is solved for the electrical potential, the Nernst- Planck equation is solved for the ion concentration. In the analysis of electroosmotic flows, when the electric double layers fully overlap or the convective effects are not negligible, the Nernst-Planck equation must be used to find the ionic distribution throughout the microchannel. The effects of surface roughness height, roughness interval spacing and roughness surface potential on flow conditions are investigated for two different configurations of the roughness, when the EDL layers fully overlap through the microchannel. The results show that in both arrangements of roughness in homogeneously charged rough channels, the flow rate decreases by increasing the roughness height. A discrepancy in the mass flow rate is observed when the roughness height is about 0.15 of the channel width, which its average is higher for the asymmetric configuration and this difference grows by increasing the roughness height. In the symmetric roughness arrangement, the mass flow rate increases until the roughness interval space is almost 1.5 times the roughness width and it decreases for higher values of the roughness interval space. For the heterogeneously charged rough channel, when the roughness surface potential ψr is less than channel surface potential ψs , the net charge density increases by getting far from the roughness surface, while in the opposite situation, when ψs is more than ψr , the net charge density decreases from roughness surface to the microchannel middle center. Increasing the roughness surface potential induces stronger electric driving force on the fluid which results in larger velocities in the flow.

FACTORES PRONOSTICOS DEL CANCER DE MAMA Y ONCOGEN HER2/NEU

Directory of Open Access Journals (Sweden)

F.J. Martín Gil

2006-08-01

Full Text Available ABSTRACT: PRONOSTIC FACTORS OF BREAST CANCER AND HER2/NEUThe breast cancer constitutes the main cause of death by cancer in women of our country. In spite of the efforts directed in campaigns of precocious detection, the incidence continues increasing in a 1% approximately per year and the rate of mortality stay constant. Therefore it is of great importance to consolidate efforts directed towards the development and use of therapeutic and diagnostic methods. The development of neoplasia is directly related to successive genetic mutations in which cellular oncogenes are involved.It is known that in case of breast cancer the Her2/neu oncogene (Human epidermal growth receptor-2 factor is amplified and/or overexpressed in approximately a 30% of the cases. The knowledge of a positive result for Her2/neu overexpression has an important value in prognosis as it is associated to a greater aggressiveness of the disease. Also, this gene can be an answer marker to certain treatments like trastuzumab. RESUMEN:El cáncer de mama (CM constituye la principal causa de muerte por cáncer en mujeres de nuestro país. A pesar de los esfuerzos dirigidos hacia las campañas de detección precoz, la incidencia sigue aumentando aproximadamente en un 1% por año y la tasa de mortalidad sigue manteniéndose constante.Es por ello de gran importancia aunar esfuerzos dirigidos al desarrollo y utilización de métodos diagnósticos y terapéuticos. El desarrollo de una neoplasia está directamente relacionado con mutaciones genéticas sucesivas en las que están involucrados oncogenes celulares.En el caso del cáncer de mama se sabe que el encogen Her2/neu (Human epidermal growth factor receptor-2 está amplificado y/o sobreexpresado en aproximadamente un 30% de los casos. El conocimiento de la positividad del mismo tiene un importante valor pronóstico asociándose a una mayor agresividad de la enfermedad. Así mismo dicho gen puede ser un marcador predictivo de respuesta

Conhecimento das estudantes universitárias da área da saúde sobre câncer de mama em mulheres The knowledge of health sciences undergraduate female students regarding women breast cancer

Directory of Open Access Journals (Sweden)

Marli Aparecida Rocha Souza

2016-04-01

Full Text Available Objetivo: Caracterizar o conhecimento de estudantes universitárias da área da saúde sobre  câncer de mama em mulheres, considerando que é uma das doença que mais acomete a mulher. Método:Pesquisa qualitativa descritiva, com 11 estudantes universitárias dos cursos de enfermagem e medicina, em uma Universidade pública do Paraná, entre abril e junho de 2012. A análise dos dados foi feita segundo os 6 passos sugeridos por Jonh W. Creswell e o referencial de Edgar Morin sobre o conhecimento e suas dimensões: a dimensão contexto, global, multidimensional e a dimensão complexo. Conclusão:O conhecimento sobre câncer de mama, vai além do conjunto de informações que o envolve,implantação de políticas públicas e programas específicos, mas também refere-se ao envolvimento e sensibilização dos profissionais que irão atuar nessa aréa.Descritores:Enfermagem; Câncer de mama; Saúde da mulher; Estudantes. Conhecimento.

The selective flow of volatile organic compounds in conductive polymer-coated microchannels

Science.gov (United States)

Hossein-Babaei, Faramarz; Hooshyar Zare, Ali

2017-02-01

Many gaseous markers of critical biological, physicochemical, or industrial occurrences are masked by the cross-sensitivity of the sensors to the other active components present at higher concentrations. Here, we report the strongly selective diffusion and drift of contaminant molecules in air-filled conductive polymer-coated microfluidic channels for the first time. Monitoring the passage of different target molecules through microchannels coated with Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) revealed that contaminants such as hexane, benzene, and CO pass through the channel unaffected by the coating while methanol, ethanol, and partly acetone are blocked. The observations are explained with reference to the selective interactions between the conductive polymer surface and target gas molecules amplified by the large wall/volume ratio in microchannels. The accumulated quantitative data point at the hydrogen bonding as the mechanism of wall adsorption; dipole-dipole interactions are relatively insignificant. The presented model facilitates a better understanding of how the conductive polymer-based chemical sensors operate.

Calculating and optimizing inter-electrode capacitances of charge division microchannel plate detectors

Energy Technology Data Exchange (ETDEWEB)

Xing, Yan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Bo, E-mail: chenb@ciomp.ac.cn [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Zhang, Hong-Ji; Wang, Hai-Feng; He, Ling-Ping [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Jin, Fang-Yuan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2016-04-01

Based on the principle of charge division microchannel plate detectors, the inter-electrode capacitances of charge division anodes which are related to electronic noise of the charge sensitive amplifier and crosstalk effect of the anode are presented. Under all the requirements of charge division microchannel plate detectors such as the imaging linearity and spatial resolution, decreasing the inter-electrode capacitances is one way to improve the imaging performance. In this paper, we illustrate the simulation process of calculating the inter-electrode capacitances. Moreover, a Wedge and Strip (WSZ) anode is fabricated with the picosecond laser micromachining process. Comparing the simulated capacitances and measured capacitances, the three-dimensional finite element method is proved to be valid. Furthermore, by adjusting the design parameters of the anode, the effects of the substrate permittivity, insulation width and the size of pitch on the inter-electrode capacitances have been analysed. The structure of the charge division anode has been optimized based on the simulation data.

Glucose Fuel Cells with a MicroChannel Fabricated on Flexible Polyimide Film

Science.gov (United States)

Sano, Ryohei; Fukushi, Yudai; Sasaki, Tsubasa; Mogi, Hiroshi; Koide, Syohei; Ikoma, Ryuta; Akatsuka, Wataru; Tsujimura, Seiya; Nishioka, Yasushiro

2013-12-01

In this work, a glucose fuel cell was fabricated using microfabrication processes assigned for microelectromechanical systems. The fuel cell was equipped with a microchannel to flow an aqueous solution of glucose. The cell was fabricated on a flexible polyimide substrate, and its porous carbon-coated aluminum (Al) electrodes of 2.8 mm in width and 11 mm in length were formed using photolithography and screen printing techniques. Porous carbon was deposited by screen printing of carbon black ink on the Al electrode surfaces in order to increase the effective electrode surface area and to absorb more enzymes on the electrode surfaces. The microchannel with a depth of 200 μm was fabricated using a hot embossing technique. A maximum power of 0.45 μW at 0.5 V that corresponds to a power density of 1.45 μW/cm2 was realized by introducing a 200 mM concentrated glucose solution at room temperature.

Glucose Fuel Cells with a MicroChannel Fabricated on Flexible Polyimide Film

International Nuclear Information System (INIS)

Sano, Ryohei; Fukushi, Yudai; Sasaki, Tsubasa; Mogi, Hiroshi; Koide, Syohei; Ikoma, Ryuta; Nishioka, Yasushiro; Akatsuka, Wataru; Tsujimura, Seiya

2013-01-01

In this work, a glucose fuel cell was fabricated using microfabrication processes assigned for microelectromechanical systems. The fuel cell was equipped with a microchannel to flow an aqueous solution of glucose. The cell was fabricated on a flexible polyimide substrate, and its porous carbon-coated aluminum (Al) electrodes of 2.8 mm in width and 11 mm in length were formed using photolithography and screen printing techniques. Porous carbon was deposited by screen printing of carbon black ink on the Al electrode surfaces in order to increase the effective electrode surface area and to absorb more enzymes on the electrode surfaces. The microchannel with a depth of 200 μm was fabricated using a hot embossing technique. A maximum power of 0.45 μW at 0.5 V that corresponds to a power density of 1.45 μW/cm 2 was realized by introducing a 200 mM concentrated glucose solution at room temperature

Distribution of Evaporating CO2 in Parallel Microchannels

DEFF Research Database (Denmark)

Brix, Wiebke; Elmegaard, Brian

2008-01-01

The impact on the heat exchanger performance due to maldistribution of evaporating CO2 in parallel channels is investigated numerically. A 1D steady state simulation model of a microchannel evaporator is built using correlations from the literature to calculate frictional pressure drop and heat...... transfer coefficients. For two channels in parallel two different cases of maldistribution are studied. Firstly, the impact of a non-uniform air flow is considered, and secondly the impact of maldistribution of the two phases in the inlet manifold is investigated. The results for both cases are compared...

Perception of Family Functioning Among Relatives of Women Who Survived Breast Cancer: Gender Differences Percepción del funcionamiento familiar entre familiares de mujeres sobrevivientes de cáncer de mama: diferencias de género Percepção do funcionamento familiar entre familiares de mulheres sobreviventes ao câncer de mama: diferenças de gênero

Directory of Open Access Journals (Sweden)

Raquel Gabrielli Biffi

2010-04-01

Full Text Available The aim of this study was to know how female and male family members perceive their family dynamics after breast cancer. Barnhill's proposal of a healthy family functional model served as the theoretical framework for this qualitative research. The data was obtained through interviews and submitted to content analysis. The results showed that, in the adaptation process to breast cancer, both genders use clear communication in order to achieve family balance and present interactions characterized by mutual and individual feelings. The responsibility for maintaining the family is attributed to the daughters, whereas the male elements show more disorganization with regard to family functions. The bond between family members of both genders who are affected by breast cancer shows important interactions in the identity process.El objetivo de este estudio fue conocer como familiares del género femenino y masculino perciben la dinámica de sus familias, después del cáncer de mama. Es una investigación de abordaje cualitativo que tomó como marco teórico el modelo de funcionamiento familiar saludable, propuesto por Barnhill. Participaron 23 familiares constituyentes de 10 familias. Los datos fueron recolectados por medio de entrevistas y sometidos al análisis de contenido. Los resultados mostraron que, en el proceso de adaptación al cáncer de mama, ambos géneros utilizan la comunicación clara para la búsqueda del equilibrio familiar y presentan interacciones caracterizadas por sentimientos de mutualidad e individuación. A las hijas es atribuida la responsabilidad por la manutención de la familia y los elementos del género masculino demuestran mayor desorganización en el funcionamiento familiar. El vínculo de los familiares de ambos géneros, que experimentan el cáncer de mama, presenta interacciones importantes en el proceso de identidad.O objetivo deste estudo foi conhecer como familiares do gênero feminino e masculino percebem a din

Perfil sócio demográfico e possíveis fatores de risco em mulheres com câncer de mama: um retrato da amazônia

Directory of Open Access Journals (Sweden)

Nathalia Santos da Penha

2013-12-01

Full Text Available O câncer de mama é a neoplasia que mais acomete mulheres no mundo e no Brasil, sendo que a ocorrência desta está relacionada com exposição a diversos fatores de risco. Este estudo observou possíveis variáveis que poderiam ser fatores de risco para o câncer de mama em 18 mulheres diagnosticadas com essa neoplasia em um Hospital Oncológico em Belém-Pará, utilizando abordagem observacional, descritiva e prospectiva. Os dados foram coletados durante cinco meses, através de um questionário acerca de aspectos sócio demográficos, hábitos de vida, características reprodutivas e antecedentes familiares de câncer de mama. A média de idade ao diagnóstico foi 49 anos (± 10,74, sendo que 44,4% estavam na faixa etária de 41 a 50 anos, 61,1% eram procedentes da Região Metropolitana de Belém e 50% tinham ensino médio. Encontrava-se em sobrepeso 44,4% das entrevistadas e 38,9% eram obesas. Observou-se que 5,6% tiveram menarca em idade inferior a 12 anos e 11,1% entraram em menopausa depois dos 50 anos. Apenas 5,6% das pacientes tiveram a primeira gestação após os 30 anos. Houve casos de aborto em 33,3% das pacientes. Todas as pacientes amamentaram, sendo que 11,1% o fizeram por menos de seis meses. Das pacientes entrevistadas, 61,1% utilizaram contraceptivos orais. Apenas 5,6% delas possuíam historia familiar de neoplasia de mama. Dessa forma, a idade avançada e a massa corpórea acima do ideal foram as variáveis com maior frequência, o que demonstra a necessidade de conhecer os fatores de risco de forma regional, para contribuir com a prevenção e diagnóstico precoce dessa neoplasia.

Practical Theology and providing service: The service through love of the Mamas Africa in the South African society

Directory of Open Access Journals (Sweden)

Amanda L. du Plessis

2014-02-01

Full Text Available A fundamental principle of the Christian faith is that man is saved by the grace and by faith in the Triune God, not by deeds. Yet, James emphasises the importance of works after the Christian has been saved. Jesus said during his ministry on earth that he did not come to be served, but to serve. Faith is therefore seen in deeds, specifically deeds of love, that is, deeds that indicate that the Christian is not leading an egocentric life anymore, but a life characterised by considering his or her fellow human beings and reaching out to them. Eighteen years after apartheid, South Africa is still a country striving to build a nation and to be healed. Marches and protests against poor public service deliveries have become a well-known sight in society. Despite the larger picture of inadequate service, there are those who serve their fellow humans and society every day. The Mamas Africa utilising the minimum resources available, are examples of people who make a difference in society every day. The concept Mama Africa indicates all women from all races who are making a difference in the South African society by promoting mutual bonding. The motivation for their deeds is a deep faith in God, who is the source of hope and a conviction that a Christian has to serve others.

Streamline-based microfluidic device

Science.gov (United States)

Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Kasdan, Harvey (Inventor)

2013-01-01

The present invention provides a streamline-based device and a method for using the device for continuous separation of particles including cells in biological fluids. The device includes a main microchannel and an array of side microchannels disposed on a substrate. The main microchannel has a plurality of stagnation points with a predetermined geometric design, for example, each of the stagnation points has a predetermined distance from the upstream edge of each of the side microchannels. The particles are separated and collected in the side microchannels.

Aislamiento de Staphylococcus aureus meticilino resistente en abscesos de mama en una Maternidad Pública

Directory of Open Access Journals (Sweden)

Cristina Boccaccio

2014-06-01

Full Text Available La mastitis y los abscesos de mama representan un factor de riesgo para el abandono de la lactancia. Se incluyen dentro de las infecciones de piel y partes blandas y comparten los cambios epidemiológicos que llevan a replantear el tratamiento empírico inicial. Se estudiaron 137 casos de abscesos de mama desde enero de 2007 a diciembre de 2011. Se analizó incidencia, días postparto, factores de riesgo, datos microbiológicos y tratamiento antibiótico. Desde 2007a 2011 se observó un constante aumento de la incidencia de casos: 0.19 vs. 0.84% (p < 0.001. Días postparto de aparición del absceso 41.9 ± 35.8 días (Media ± DE, primiparidad 70.6%. Los factores de riesgo más frecuentemente encontrados fueron grietas del pezón e ingurgitación mamaria (95%. Staphylococcus aureus (SA fue el responsable de 82.3 a 95.0% de los abscesos según los años; la resistencia a oxacilina de las cepas de SA superó el 60%. Las cepas aisladas de SA meticilino resistentes (SAMR fueron sensibles a eritromicina clindamicina, gentamicina, rifampicina, ciprofloxacina y trimetroprima-sulfametoxasol en diferentes porcentajes según los años. Requirieron drenaje el 100% de los casos; en 60% el tratamiento empírico inicial fue inadecuado. Continuaron amamantando 90% de las madres. Estos datos enfatizan la necesidad de prevenir los factores de riesgo: grietas del pezón e ingurgitación mamaria. La modificación del tratamiento antibiótico inicial requiere el estudio bacteriológico de las infecciones de piel y partes blandas dado que la prevalencia de SAMR no es uniforme y varía en diferentes poblaciones y ubicaciones geográficas.

Single-phase liquid flow forced convection under a nearly uniform heat flux boundary condition in microchannels

KAUST Repository

Lee, Man

2012-02-22

A microchannel heat sink, integrated with pressure and temperature microsensors, is utilized to study single-phase liquid flow forced convection under a uniform heat flux boundary condition. Utilizing a waferbond-and-etch- back technology, the heat source, temperature and pressure sensors are encapsulated in a thin composite membrane capping the microchannels, thus allowing experimentally good control of the thermal boundary conditions. A three-dimensional physical model has been constructed to facilitate numerical simulations of the heat flux distribution. The results indicate that upstream the cold working fluid absorbs heat, while, within the current operating conditions, downstream the warmer working fluid releases heat. The Nusselt number is computed numerically and compared with experimental and analytical results. The wall Nusselt number in a microchannel can be estimated using classical analytical solutions only over a limited range of the Reynolds number, Re: both the top and bottom Nusselt numbers approach 4 for Re < 1, while the top and bottom Nusselt numbers approach 0 and 5.3, respectively, for Re > 100. The experimentally estimated Nusselt number for forced convection is highly sensitive to the location of the temperature measurements used in calculating the Nusselt number. © 2012 IOP Publishing Ltd.

Single-phase liquid flow forced convection under a nearly uniform heat flux boundary condition in microchannels

KAUST Repository

Lee, Man; Lee, Yi-Kuen; Zohar, Yitshak

2012-01-01

A microchannel heat sink, integrated with pressure and temperature microsensors, is utilized to study single-phase liquid flow forced convection under a uniform heat flux boundary condition. Utilizing a waferbond-and-etch- back technology, the heat source, temperature and pressure sensors are encapsulated in a thin composite membrane capping the microchannels, thus allowing experimentally good control of the thermal boundary conditions. A three-dimensional physical model has been constructed to facilitate numerical simulations of the heat flux distribution. The results indicate that upstream the cold working fluid absorbs heat, while, within the current operating conditions, downstream the warmer working fluid releases heat. The Nusselt number is computed numerically and compared with experimental and analytical results. The wall Nusselt number in a microchannel can be estimated using classical analytical solutions only over a limited range of the Reynolds number, Re: both the top and bottom Nusselt numbers approach 4 for Re < 1, while the top and bottom Nusselt numbers approach 0 and 5.3, respectively, for Re > 100. The experimentally estimated Nusselt number for forced convection is highly sensitive to the location of the temperature measurements used in calculating the Nusselt number. © 2012 IOP Publishing Ltd.

Asymmetry of blood flow and cancer cell adhesion in a microchannel with symmetric bifurcation and confluence.

Science.gov (United States)

Ishikawa, Takuji; Fujiwara, Hiroki; Matsuki, Noriaki; Yoshimoto, Takefumi; Imai, Yohsuke; Ueno, Hironori; Yamaguchi, Takami

2011-02-01

Bifurcations and confluences are very common geometries in biomedical microdevices. Blood flow at microchannel bifurcations has different characteristics from that at confluences because of the multiphase properties of blood. Using a confocal micro-PIV system, we investigated the behaviour of red blood cells (RBCs) and cancer cells in microchannels with geometrically symmetric bifurcations and confluences. The behaviour of RBCs and cancer cells was strongly asymmetric at bifurcations and confluences whilst the trajectories of tracer particles in pure water were almost symmetric. The cell-free layer disappeared on the inner wall of the bifurcation but increased in size on the inner wall of the confluence. Cancer cells frequently adhered to the inner wall of the bifurcation but rarely to other locations. Because the wall surface coating and the wall shear stress were almost symmetric for the bifurcation and the confluence, the result indicates that not only chemical mediation and wall shear stress but also microscale haemodynamics play important roles in the adhesion of cancer cells to the microchannel walls. These results provide the fundamental basis for a better understanding of blood flow and cell adhesion in biomedical microdevices.

Mathematical modelling of liquid meniscus shape in cylindrical micro-channel for normal and micro gravity conditions

Science.gov (United States)

Marchuk, Igor; Lyulin, Yuriy

2017-10-01

Mathematical model of liquid meniscus shape in cylindrical micro-channel of the separator unit of condensing/separating system is presented. Moving liquid meniscus in the 10 μm cylindrical microchannel is used as a liquid lock to recover the liquid obtained by condensation from the separators. The main goal of the liquid locks to prevent penetration of a gas phase in the liquid line at the small flow rate of the condensate and because of pressure fluctuations in the vapor-gas-liquid loop. Calculation of the meniscus shape has been performed for liquid FC-72 at different values of pressure difference gas - liquid and under normal and micro gravity conditions.

Ma ma (2015: un reflejo de la mujer española con cáncer de mama

Directory of Open Access Journals (Sweden)

Clara Peralta?Nueno et al.

2017-03-01

Full Text Available Ma ma (2015 es una película de drama española dirigida por Julio Medem y producida por Morena Films. Esta película narra la historia de la vida de Magda cuyo personaje es interpretado por Penélope Cruz. Tras serle diagnosticado un cáncer de mama, Magda, una maestra en paro, no sabrá cómo actuar ni de qué manera cambiará esta enfermedad su vida, pero poco a poco sacará a la superficie toda su energía vital. El cáncer de mama representa el tipo de cáncer más frecuente en la mujer. Aunque la mayoría de los factores de riesgo identificados pueden ser modificables, los sistemas de salud se concentran en actividades que permiten fortalecer la prevención primaria y actividades de prevención secundaria y terciaria. La detección temprana y el tratamiento adecuado son indispensables para luchar contra esta enfermedad. El proceso emocional generado por la presencia de cáncer, conlleva un mecanismo de reconstitución psíquico que permite a la paciente conformar una respuesta a los desafíos orgánicos, cognitivos, sociales y emocionales a los cuales se ve enfrentada. Dicho proceso es favorecido entre otros factores por contar con una red de apoyo socio?familiar sólida.

Linfonodo sentinela: um novo conceito no tratamento cirúrgico do câncer de mama

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Cícero de Andrade Urban

Full Text Available O linfonodo sentinela é o primeiro linfonodo que recebe a drenagem linfática proveniente do câncer de mama. A sua detecção tem a finalidade de predizer o estado da axila e evitar o esvaziamento axilar nos pacientes sem comprometimento metastático. Os autores realizaram uma ampla revisão da literatura, envolvendo os aspectos cirúrgicos, de Medicina Nuclear e de Anatomia Patológica do linfonodo sentinela. Muitos estudos demonstraram a eficácia do linfonodo sentinela em predizer o comprometimento axilar. Entretanto, existem várias técnicas empregadas para a identificação desse linfonodo, sem haver ainda um consenso em relação ao método mais adequado e reproduzível. A associação do corante vital com o probe, até o presente, é a que tem apresentado os melhores resultados. Também não existe uma padronização do exame patológico intra-operatório do linfonodo sentinela e os índices de falso-negativos encontrados são bastante variáveis. A biópsia do linfonodo sentinela pode oferecer uma alternativa segura à dissecção axilar e com menos efeitos colaterais nos pacientes com axila clinicamente negativa. Entretanto alguns pontos conflitantes devem ser resolvidos antes que o método passe a ser utilizado na prática com o câncer de mama. O objetivo desse trabalho foi discutir os principais aspectos envolvidos no desenvolvimento e na aplicação dessa técnica.

Amorphous silicon-based microchannel plates

International Nuclear Information System (INIS)

Franco, Andrea; Riesen, Yannick; Wyrsch, Nicolas; Dunand, Sylvain; Powolny, François; Jarron, Pierre; Ballif, Christophe

2012-01-01

Microchannel plates (MCP) based on hydrogenated amorphous silicon (a-Si:H) were recently introduced to overcome some of the limitations of crystalline silicon and glass MCP. The typical thickness of a-Si:H based MCPs (AMCP) ranges between 80 and 100 μm and the micromachining of the channels is realized by deep reactive ion etching (DRIE). Advantages and issues regarding the fabrication process are presented and discussed. Electron amplification is demonstrated and analyzed using Electron Beam Induced Current (EBIC) technique. The gain increases as a function of the bias voltage, limited to −340 V on account of high leakage currents across the structure. EBIC maps on 10° tilted samples confirm that the device active area extend to the entire channel opening. AMCP characterization with the electron beam shows gain saturation and signal quenching which depends on the effectiveness of the charge replenishment in the channel walls.

Lipoestructura y relleno del polo superior de la mama frente a implantes Structural fat graft and lipofilling of mammary upper pole versus mammary implants

Directory of Open Access Journals (Sweden)

J.M. Cervilla Lozano

2012-09-01

Full Text Available La lipoestructura mamaria ofrece nuevas alternativas de tratamiento en la cirugía estética de aumento mamario, cumpliendo en algunos casos las expectativas esperadas y en otros no. Analizamos este hecho en 4 tipos de aplicación de lipoestructura mamaria que hemos venido realizando en los últimos años, centrándonos en un aspecto importante de esta cirugía que es el relleno del polo superior de la mama. Los tipos de aplicación empleados son: aumento mamario simple mediante lipoestructura en comparación con implantes; pexia más lipoestructura frente a pexia más implantes mamarios; reconstrucción de mama tuberosa mediante lipoestructura o implantes y finalmente, relleno periprotésico mediante lipoestructura en mamas sometidas a cirugía de aumento mamario con implantes. En definitiva, podríamos resumir este trabajo en una frase diciendo que la lipoestructura mamaria, a nuestro juicio, no sirve si lo que prima es conseguir el relleno del polo superior de la mama, siendo en este caso de elección la colocación de implantes mamarios. No obstante, en alguno de los casos señalados no solo es una alternativa, sino que obtiene resultados superiores a los logrados sólamente con implantes.The mammary structural fat graft offers news treatment options in breast augmentation cosmetic surgery, but it sometimes meets expectations and sometimes doesn´t. We analyze 4 different types of lipostructure mammary applications that we have been using in the last years, focused in an important aspect of this surgery as it´s the filling of the upper mammary pole. These applications are: mammary augmentation by simple structural fat compared with the use of mammary implants; structural fat graft and mastopexy versus implants and mastopexy; tuberous breast reconstruction using structural fat graft or implants and finally, periprosthetic filling in breast augmentation with mammary implants using structural fat graft. In short, we could summarize this paper

Cáncer de mama y de ovario: significados, dolor y sufrimiento en la cotidianidad de mujeres pacientes

OpenAIRE

Alicia M. Tinoco García

2012-01-01

El presente estudio tiene por objetivo conocer, explicar y comprender los significados, el dolor y sufrimiento en la cotidianidad de mujeres que padecen cáncer de mama y de ovario. Aborda la subjetividad e intersubjetividad de las pacientes en su realidad cotidiana y contexto sociocultural. La investigación encuentra sustento teórico en la Sociología de la salud, Antropología de la salud y en otras ciencias de frontera que abordan problemas de salud-enfermedad, dolor y sufrimiento; así como e...

Mortalidade por câncer de mama e câncer de colo do útero em município de porte médio da Região Sudeste do Brasil, 1980-2006

OpenAIRE

Rodrigues,Anselmo Duarte; Bustamante-Teixeira,Maria Teresa

2011-01-01

Analisar a tendência da mortalidade por câncer de mama e câncer de colo do útero em mulheres residentes no Município de Juiz de Fora, Minas Gerais, Brasil, no período de 1980 a 2006. Os dados sobre os óbitos foram obtidos do Sistema de Informação sobre Mortalidade; as taxas de mortalidade específicas foram calculadas por idade e padronizadas pela população mundial. Para análise de tendência, foram aplicados modelos de regressão polinomial. O câncer de mama foi a principal causa de óbito entre...

Mecanismos cognitivos del optimismo en cáncer de mama : relaciones con la calidad de vida /

OpenAIRE

Pastells Pujol, Sílvia,

2017-01-01

Departament responsable de la tesi: Departament de Psicologia Bàsica, Evolutiva i de l'Educació Introducció El càncer de mama és la patologia oncològica més diagnosticada a Espanya i al món occidental. El seu diagnòstic i tractament suposen una situació estressant que pot durar mesos o fins i tot cronificar-se quan apareixen recurrències. Les diferents fases de la malaltia desencadenen diferents conseqüències físiques, emocionals i socials que afecten la vida diària de les pacients. Un del...

Depressão e ansiedade nos cuidadores de mulheres em fase terminal de câncer de mama e ginecológico Depression and anxiety in caregivers of terminally-ill breast and gynecological cancer patients

OpenAIRE

Vera Lucia Rezende; Sophie Françoise Mauricette Derchain; Neury José Botega; Luis Otávio Sarian; Daniela Landulfo Vial; Sirlei Siani Morais

2005-01-01

OBJETIVO: avaliar a freqüencia de ansiedade e depressão em cuidadores principais de mulheres em fase terminal de câncer de mama ou genital. MÉTODOS: para este estudo de corte transversal foram incluídos 133 cuidadores de pacientes sem possibilidades curativas, internadas no Centro de Atenção Integral à Saúde da Mulher, entre agosto de 2002 e maio de 2004. Das pacientes incluídas, 71 apresentavam câncer de mama e 62, câncer ginecológico. Foi aplicada a Escala Hospitalar de Ansiedade e Depressã...

Ansiedade no período pré-operatório de cirurgias de mama: estudo comparativo entre pacientes com suspeita de câncer e a serem submetidas a procedimentos cirúrgicos estéticos

OpenAIRE

Alves, Maria Luiza Melo; Pimentel, Adriana Jucá; Guaratini, Álvaro Antônio; Marcolino, José Álvaro Marques; Gozzani, Judymara Lauzi; Mathias, Ligia Andrade da Silva Telles

2007-01-01

JUSTIFICATIVA E OBJETIVOS: A avaliação da ansiedade não faz parte da rotina da avaliação pré-anestésica (APA), o que faz com que situações especiais em que o estado emocional dos pacientes possa estar alterado, passem despercebidas pelo anestesiologista. Este estudo visou comparar, no momento da APA ambulatorial, fatores de risco, intensidade e prevalência de ansiedade em pacientes com suspeita de câncer de mama e a serem submetidas a procedimentos cirúrgicos estéticos de mama. MÉTODO: Após a...

Parametric Study on the Characteristics of Multiphase Laminar Flow with Density Difference in Various Microchannels

International Nuclear Information System (INIS)

Paek, Seung Ho; Kim, Dong Sung; Choi, Young Ki

2009-01-01

In this paper, we have performed a parametric study on the characteristics of multiphase laminar flow with density difference in various microchannels. The interface between multiphase fluids is rotated by the gravitational forces induced by density difference. The numerical simulations were carried out via commercial CFD package to study the characteristics of multiphase laminar flow. The results of the numerical simulations in this study were verified by comparing with the previously reported experimental results in the literature. We have also proposed a new dimensionless relationship between dimensionless rotation angle of interface and dimensionless parameters are proposed for square microchannels with various aspect ratios. The dimensionless relationship could be widely applied to the reliable design of various microfluidic devices dealing with multiphase laminar flow

A microchannel plate X-ray multiplier with rising-time less than 170 ps

International Nuclear Information System (INIS)

Zhao Shicheng; Ouyang Bin

1987-01-01

The time reponse of a microchannel plate X-ray multiplier has been improved considerably by using a coupling construction of coaxial tapers. The experimental calibration results with laser plasma X-ray source show that the rising-time of the multiplier is less than 170 ps

Improved lifetime of microchannel-plate PMTs

Energy Technology Data Exchange (ETDEWEB)

Lehmann, A., E-mail: lehmann@physik.uni-erlangen.de [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Britting, A.; Eyrich, W.; Uhlig, F. [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); and others

2014-12-01

The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈6C/cm{sup 2} integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

New recommendations from the United States Government on breast cancer screening Nuevas recomendaciones del Gobierno de los Estados Unidos sobre el tamizaje del cáncer de mama

Directory of Open Access Journals (Sweden)

2002-03-01

Full Text Available En los últimos años ha habido grandes controversias y debates sobre la eficacia de diferentes métodos de detección del cáncer de mama. En un esfuerzo por proporcionar orientaciones más claras tanto a las mujeres como a los profesionales de la salud, un grupo de expertos reunido por el Gobierno de los Estados Unidos de América, el llamado U.S. Preventive Services Task Force (USPSTF, publicó en febrero de 2002 un informe en el que se afirma que la mamografía permite salvar vidas y que su realización debería comenzar en la quinta década de la vida de la mujer. Este grupo de expertos dice también que no hay datos suficientes para hacer recomendaciones a favor o en contra de otros dos métodos de detección: el examen clínico de la mama y la autoexploración mamaria rutinaria. El presente documento resume las recomendaciones del informe del USPSTF, así como las principales consideraciones clínicas y pruebas científicas que presentó en áreas como la exactitud y fiabilidad de las pruebas de detección, la eficacia de la detección temprana del cáncer de mama, cuándo detener el tamizaje, el intervalo de tiempo más apropiado entre las pruebas y los potenciales perjuicios del tamizaje.

Optimal Design of Silicon-based Chips for Piezo-induced Ultrasound Resonances in Embedded Microchannels

DEFF Research Database (Denmark)

Garofalo, F.; Laurell, T.; Bruus, Henrik

2015-01-01

constituting the device (the piezo transducer, the silicon walls, the fluid-filled microchannel, and the glass lid) allows for the introduction of the weak formulation used in the finite element discretization of the equations describing the system in its oscillatory regime. Additionally, the knowledge...... of the Lagrangian density leads to the derivation of the correct structure of the Hamiltonian density, i.e. the energy density, which is important for the quantification of the energy content of the whole system and its individual parts. Specifically, the energy content of the embedded microchannel is quantified...... by means of the acoustofluidic yield η defined as the ratio between the energy in the channel and the total energy. From the standpoint of acoustophoretic application, the introduction of the acoustophoretic mean orientation allows us to identify the frequencies for which an acoustophoretic effect, i...

Hydrodynamic dispersion in a combined magnetohydrodynamic- electroosmotic-driven flow through a microchannel with slowly varying wall zeta potentials

Science.gov (United States)

Vargas, C.; Arcos, J.; Bautista, O.; Méndez, F.

2017-09-01

The effective dispersion coefficient of a neutral solute in the combined electroosmotic (EO) and magnetohydrodynamic (MHD)-driven flow of a Newtonian fluid through a parallel flat plate microchannel is studied. The walls of the microchannel are assumed to have modulated and low zeta potentials that vary slowly in the axial direction in a sinusoidal manner. The flow field required to obtain the dispersion coefficient is solved using the lubrication approximation theory. The solution of the electrical potential is based on the Debye-Hückel approximation for a symmetric (Z :Z ) electrolyte solution. The EO and MHD effects, together with the variations in the zeta potentials of the walls, are observed to notably modify the axial distribution of the effective dispersion coefficient. The problem is formulated for two cases of the zeta potential function. Note that the dispersion coefficient primarily depends on the Hartmann number, on the ratio of the half height of the microchannel to the Debye length, and on the assumed variation in the zeta potentials of the walls.

VOF Modeling and Analysis of the Segmented Flow in Y-Shaped Microchannels for Microreactor Systems

Directory of Open Access Journals (Sweden)

Xian Wang

2013-01-01

Full Text Available Microscaled devices receive great attention in microreactor systems for producing high renewable energy due to higher surface-to-volume, higher transport rates (heat or/and mass transfer rates, and other advantages over conventional-size reactors. In this paper, the two-phase liquid-liquid flow in a microchannel with various Y-shaped junctions has been studied numerically. Two kinds of immiscible liquids were injected into a microchannel from the Y-shaped junctions to generate the segment flow mode. The segment length was studied. The volume of fluid (VOF method was used to track the liquid-liquid interface and the piecewise-liner interface construction (PLIC technique was adopted to get a sharp interface. The interfacial tension was simulated with continuum surface force (CSF model and the wall adhesion boundary condition was taken into consideration. The simulated flow pattern presents consistence with our experimental one. The numerical results show that a segmented flow mode appears in the main channel. Under the same inlet velocities of two liquids, the segment lengths of the two liquids are the same and depend on the inclined angles of two lateral channels. The effect of inlet velocity is studied in a typical T-shaped microchannel. It is found that the ratio between the lengths of two liquids is almost equal to the ratio between their inlet velocities.

A Flexible Ascorbic Acid Fuel Cell with a Microchannel Fabricated using MEMS Techniques

Science.gov (United States)

Mogi, Hiroshi; Fukushi, Yudai; Koide, Syohei; Sano, Ryohei; Sasaki, Tsubasa; Nishioka, Yasushiro

2013-12-01

We fabricated a miniature ascorbic acid fuel cells equipped with a microchannel for the circulation of ascorbic acid (AA) solution using micro electronic mechanical system techniques. The fuel cell was fabricated on a flexible polyimide substrate, and its porous carbon-coated aluminium (Al) electrodes of 2.8 mm in width and 11 mm in length were formed using photolithography and screen-printing techniques. The porous carbon was deposited by screen-printing of carbon-black ink on the Al electrode surfaces in order to increase the effective electrode surface area and to absorb more enzymes on the cathode surface. The microchannel with a depth of 200 μm was fabricated using a hot-embossing technique. A maximum power of 0.60 μW at 0.58 V that corresponds to a power density of 1.83 μW/cm2 was realized by introducing a 200 mM concentrated AA solution at room temperature.

Continuous particle separation in a serpentine microchannel via negative and positive dielectrophoretic focusing

International Nuclear Information System (INIS)

Church, Christopher; Zhu, Junjie; Nieto, Juan; Keten, Gyunay; Ibarra, Erl; Xuan, Xiangchun

2010-01-01

Dielectrophoresis (DEP) has been widely used to focus and separate cells and particles in microfluidic devices. This work first demonstrates negative and positive dielectrophoretic focusing of particles in a serpentine microchannel by changing only the electric conductivity of the suspending fluid. Due to the channel turn-induced dielectrophoretic force, particles are focused to either the centerline or the sidewalls of the channel when their electric conductivity is lower (i.e. negative DEP) or higher (i.e. positive DEP) than that of the fluid. These distinctive dielectrophoretic focusing phenomena in a serpentine microchannel are then combined to implement a continuous separation between particles of different sizes and electric conductivities. Such separation eliminates the fabrication of in-channel microelectrodes or micro-insulators that are typically required in DEP-based separation techniques. A numerical model is also developed to predict the particle motion, and the simulation results agree reasonably with the observed particle focusing and separation behaviors.

Three-dimensional particle-in-cell simulation on gain saturation effect of microchannel plate

Energy Technology Data Exchange (ETDEWEB)

Wang, Qiangqiang; Yuan, Zheng; Cao, Zhurong, E-mail: cao33jin@aliyun.com; Deng, Bo; Chen, Tao; Deng, Keli [Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

2016-07-15

We present here the results of the simulation work, using the three-dimensional particle-in-cell method, on the performance of the lead glass microchannel plate under saturated state. We calculated the electron cascade process with different DC bias voltages under both self-consistent condition and non-self-consistent condition. The comparative results have demonstrated that the strong self-consistent field can suppress the cascade process and make the microchannel plate saturated. The simulation results were also compared to the experimental data and good agreement was obtained. The simulation results also show that the electron multiplication process in the channel is accompanied by the buildup process of positive charges in the channel wall. Though the interactions among the secondary electron cloud in the channel, the positive charges in the channel wall, and the external acceleration field can make the electron-surface collision more frequent, the collision energy will be inevitably reduced, thus the electron gain will also be reduced.

Estadiamento e grau de resiliência do sobrevivente ao câncer de mama Staging and resilience degree in breast cancer survivors

Directory of Open Access Journals (Sweden)

Niviane Genz

2016-10-01

Full Text Available Objetivo: Investigar o grau de resiliência e de estadiamento frente aos fatores sociodemográficos dos sobreviventes ao câncer de mama em acompanhamento em um serviço de oncologia. Métodos: Estudo quantitativo, amostra de 112 sobreviventes ao câncer de mama. Foram selecionadas variáveis sociodemográficas, estadiamento clínico, tempo de sobrevida e escala de resiliência. Análise no epi-info 6.04 e teste exato de fischer. Aprovação do Comitê de Ética da Faculdade de Enfermagem da UFPel  nº 31/2009. Resultados: média de idade de 46,2 anos, 60,71% estadiamento II, 81,25% eram brancas, 40,18% com escolaridade entre 5-8 anos, 52,68% casados, 73,32% viveu em zona urbana, 41,96% apresentou alta resiliência e 48,21% mantinha-se em acompanhamento entre 1-3 anos. Conclusão: O estadiamento não está associado ao grau de resiliência, mas sim à idade e tempo de sobrevida confirmando os achados em outros estudos.

Numerical Study of Surfactant Dynamics during Emulsification in a T-Junction Microchannel.

Science.gov (United States)

Riaud, Antoine; Zhang, Hao; Wang, Xueying; Wang, Kai; Luo, Guangsheng

2018-04-18

Microchannel emulsification requires large amounts of surfactant to prevent coalescence and improve emulsions lifetime. However, most numerical studies have considered surfactant-free mixtures as models for droplet formation in microchannels, without taking into account the distribution of surfactant on the droplet surface. In this paper, we investigate the effects of nonuniform surfactant coverage on the microfluidic flow pattern using an extended lattice-Boltzmann model. This numerical study, supported by micro-particle image velocimetry experiments, reveals the likelihood of uneven distribution of surfactant during the droplet formation and the appearance of a stagnant cap. The Marangoni effect affects the droplet breakup by increasing the shear rate. According to our results, surfactant-free and surfactant-rich droplet formation processes are qualitatively different, such that both the capillary number and the Damköhler number should be considered when modeling the droplet generation in microfluidic devices. The limitations of traditional volume and pressure estimation methods for determining the dynamic interfacial tension are also discussed on the basis of the simulation results.

Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector

CERN Document Server

Andresen, G B; Bowe, P D; Bray, C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jørgensen, L V; Kerrigan, S J; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Yamazaki, Y

2009-01-01

A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton extractions is compared to that of electrons and positrons.

Coupling between electroosmotically driven flow and bipolar faradaic depolarization processes in electron-conducting microchannels

NARCIS (Netherlands)

Qian, S.Z.; Duval, J.F.L.

2006-01-01

A quantitative theory is proposed for the analysis of steady electroosmotically driven flows within conducting cylindrical microchannels. Beyond a threshold value of the electric field applied in the electrolyte Solution and parallel to the conducting surface, electrochemical oxidation and reduction

Câncer de mama e sofrimento psicológico: aspectos relacionados ao feminino El cáncer de mama y el sufrimiento psicológico: aspectos relacionados con el femenino Breast cancer and psychological suffering: female-related aspects

OpenAIRE

Lucia Cecilia da Silva

2008-01-01

No Brasil e no mundo a incidência do câncer de mama vem aumentando e aparecendo cada vez mais cedo na vida da mulher. O tratamento envolve mastectomia, quimioterapia e radioterapia, que, pelos seus efeitos físicos, podem comprometer em variados graus a auto-estima, a imagem corporal e a identidade feminina daquelas que recebem o diagnóstico da doença. Além disso, em nossa sociedade o câncer adquiriu significados relacionados a culpa, punição, deterioração, dor e morte, agravando o sofrimento ...

Condutas na prevenção secundária do câncer de mama e fatores associados Breast cancer's secondary prevention and associated factors

Directory of Open Access Journals (Sweden)

Marcelo Leal Sclowitz

2005-06-01

Full Text Available OBJETIVO: Avaliar a prevalência de condutas na prevenção secundária do câncer de mama e fatores associados. MÉTODOS: Foi realizado estudo transversal de base populacional na cidade de Pelotas, RS, em 2002, com amostra de 879 mulheres de 40 a 69 anos. Foram coletadas informações sobre variáveis demográficas, socioeconômicas, comportamentais, biológicas e referentes ao manejo médico. A análise estatística das variáveis foi realizada utilizando o método de regressão de Poisson. RESULTADOS: A prevalência do "hábito de realizar o auto-exame" encontrada foi de 83,5% (IC 95%: 80,9-85,9, sendo que, dessas mulheres, 80,4% (IC 95%: 77,3-83,2 o realizavam ao menos uma vez ao mês. A prevalência de "exame clínico de mamas" foi de 83,3% (IC 95%: 80,6-85,7. "Mamografia alguma vez na vida" mostrou prevalência de 70% (IC 95%: 66,8-73,0, sendo que 83,7% (IC 95%: 80,5-86,6 realizaram a última mamografia há dois anos ou menos. Das entrevistadas, 62% (IC 95%: 58,7-65,2 consultaram ginecologista ao menos uma vez no último ano. Os fatores associados a maiores prevalências das condutas na prevenção secundária do câncer de mama foram: pertencer às classes sociais mais altas; ter a maior combinação de fatores de risco para neoplasia mamária; ter história familiar de câncer de mama; fazer uso de terapia de reposição hormonal e ter sido submetida à biópsia por patologia mamária. CONCLUSÕES: As medidas preventivas para o câncer de mama vêm sendo bastante utilizadas quantitativamente; entretanto, os dados apontam para limitações em relação à sua adequação. O nível socioeconômico parece ser o principal determinante do acesso à consulta ginecológica e, conseqüentemente, às demais condutas na prevenção secundária do câncer de mama.OBJECTIVE: To evaluate the prevalence of secondary prevention of breast cancer and associated factors. METHODS: A population-based cross-sectional study was conducted in the city of

Experiencia de cuidadores familiares de mujeres con cáncer de mama: una revisión integradora

Directory of Open Access Journals (Sweden)

María Mercedes Moreno-González

2018-01-01

Full Text Available Objetivo: identificar la evidencia científica de enfermería relacionada con la experiencia de los cuidadores familiares de mujeres con cáncer de mama.Metodología: revisión integradora siguiendo los lineamientos de Ganong; búsqueda en bases de datos: EMBASE, OVID, PUBMED, SAGE journals, SCIELO, Google Academic, ISI Web of Science y SCOPUS, artículos publicados entre los años 2000 y 2016. Resultados: se incluyeron 18 artículos producto de investigaciones primarias de tipo cualitativo, cuyos referentes teórico-metodológicos fueron fenomenología y teoría fundamentada, las técnicas de recolección de datos fueron la entrevista semiestructurada y en profundidad. Se presentan y discuten como hallazgos las siguientes categorías: impacto del diagnóstico; lo que implica ser cuidador; efectos en el cuidador; estrategias de afrontamiento; cambios en los roles y las relaciones; apoyo social. Conclusiones: las características de los cuidadores son variables, es necesario conocer sobre la cultura y recursos propios de cada contexto. Los cuidadores requieren información clara y oportuna en relación su función y las habilidades a desarrollar, especialmente para otorgar apoyo emocional. Es necesaria la indagación de dichas experiencias en el contexto mexicano. Las relaciones padres e hijos en las familias de mujeres con cáncer de mama es un asunto poco estudiado, se requieren futuros estudios en este tema.

El proceso de adaptación en las mujeres con cáncer de mama The adaptation process of breast cancer women

Directory of Open Access Journals (Sweden)

Yenly Catherine Londoño Calle

2009-03-01

Full Text Available Objetivo: descubrir el proceso de adaptación de las mujeres para enfrentarse al cáncer de mama, a sus nuevas condiciones de vida y estado de salud dentro de su contexto sociocultural. Metodología: estudio cualitativo apoyado en la Teoría Fundamentada, mediante la realización de entrevistas en profundidad a veinte mujeres que recibieron tratamiento para cáncer de mama, residentes en la ciudad de Medellín, Colombia durante el período de 2005 a 2007. Resultados: el alcance del análisis llegó hasta un ordenamiento conceptual, evidenciando un proceso de adaptación en cuatro etapas: 1. Descubriendo la enfermedad, 2. Aceptando la enfermedad, 3. Venciendo la enfermedad y 4. Adaptándome a un nuevo cuerpo y a una nueva vida. Conclusiones: la adaptación de las mujeres con cáncer de mama es un proceso complejo por cuanto deben enfrentar los múltiples desequilibrios que afectan su dimensión emocional, física, mental y social.This article looks at the adaptation processes that have to undertake women when facing breast cancer. Objective: discover the process of adaptation to their new life conditions and state of health within a sociocultural context. Methodology: qualitative study supported in the Founded Theory by means of in depth interviews to a sample of twenty resident women who received treatment for breast cancer in the city of Medellín, Colombia from 2005 to 2007. Results: the reach of the analysis allowed establishing a conceptual order, showing a process of adaptation in four stages, denominated thus: 1. Discovering the disease, 2. Accepting the disease, 3. Overcoming disease, and 4. Adapting to a new body and a new life. Conclusions: the adaptation of the breast cancer women with breast cancer is a complex process because they must face continuously the multiple imbalances that affect their emotional, physical, mental and social dimensions

Conhecimento dos métodos para diagnóstico do câncer de mama entre estudantes de medicina Knowledge regarding breast cancer diagnosis among medical students

Directory of Open Access Journals (Sweden)

Nilceana Maya Aires

1999-04-01

Full Text Available Objetivos: avaliar o nível de conhecimento de noções básicas do diagnóstico do câncer de mama entre os alunos de medicina; promover a discussão entre eles e avaliar o aproveitamento dos alunos do 5º ano médico, após cursar a Disciplina de Ginecologia. Métodos: por meio de questionários aplicados a 348 alunos do total de 550 alunos, do 1º ao 5º ano do curso médico, buscaram-se informações a respeito do conhecimento básico do diagnóstico do câncer de mama. Dos 348 questionários aplicados, 55 (16% foram respondidos por estudantes do 5º ano que haviam cursado a Disciplina de Ginecologia. Destes, 43% eram mulheres, 62% tinham familiares médicos e 17% história familiar de câncer de mama. Resultados: em relação ao conhecimento dos métodos diagnósticos, 84% dos alunos acertaram o sinal mais freqüente do câncer de mama; 34%, o melhor método de rastreio; 49%, quando indicar a mamografia em mulheres assintomáticas; 37%, a periodicidade preconizada da mamografia após 50 anos e 24%, quando associar o ultra-som à mamografia para detecção do câncer de mama. Os alunos do 5º ano apresentaram um índice de acerto para todas as perguntas significativamente maior que os demais. O sexo só apresentou diferença em relação ao maior conhecimento pelas mulheres quanto ao melhor período para o auto-exame e quando indicar a associação do ultra-som à mamografia. A presença de familiares médicos e a história familiar de câncer de mama não influenciaram as respostas. Conclusão: mesmo entre acadêmicos de medicina ainda é grande a desinformação a respeito do diagnóstico do câncer de mama. Não obstante, após cursar a disciplina, esse conhecimento aumenta significativamente.Purpose: to evaluate how knowledgeable medical students at the Universidade Federal de Goiás were concerning the basic diagnostic principles breast cancer. The study also aimed at promoting a debate among the students and at assessing the

Programa de actividades acuáticas para mujeres que han sido operadas de cáncer de mama

OpenAIRE

Muñoz Ortega, Alberto

2015-01-01

Objetivo: Crear un programa de actividades acuáticas para mujeres que han sido operadas de cáncer de mama y así mejorar su calidad de vida. Método: Se desarrollará una programación de actividades acuáticas, donde se incluirán sesiones de aquagym, aquarobic, sesiones terapéuticas, aquarunning y sesiones lúdicas. Este programa se llevará a cabo durante 4 meses con dos sesiones a la semana. Con esta variedad de actividades conseguiremos trabajar todos aquellos aspectos físicos, psicológicos y...

Rastreamento do câncer de mama: aspectos relacionados ao médico Breast cancer screening: physicians related issues.

Directory of Open Access Journals (Sweden)

Eduardo Rodrigues Godinho

2004-04-01

Full Text Available OBJETIVO: Reconhecer as características dos médicos do Estado de Goiás, suas condutas, crenças, opiniões e conhecimentos sobre câncer de mama. MATERIAIS E MÉTODOS: Foram enviados 592 questionários aos ginecologistas, mastologistas e geriatras de Goiás. Os principais aspectos pesquisados foram: 1 - características sócio-demográficas (sexo, idade, ano de formatura, atuação em serviços públicos ou particulares; 2 - capacidade de reconhecimento dos fatores de risco para câncer de mama; 3 - atividades educativas desenvolvidas pelos médicos; 4 - percepção de elementos limitadores ao rastreamento; 5 - perguntas genéricas. RESULTADOS: Os questionários respondidos totalizaram 105 (21,2%; 70,5% dos médicos eram do sexo masculino; idade média de 43,9 anos (26 a 70 anos; 73,5% tinham menos de 20 anos de formado; 88,6% ginecologistas, 4,8% ginecologistas/mastologistas, 3,8% mastologistas, 2,8% geriatras; 62,5% atuavam na rede pública e particular simultaneamente. Apenas 13,3% identificaram os cinco fatores de risco apresentados. Cerca de 95% responderam ter participado de cursos de atualização nos dois anos que antecederam a pesquisa. Outros resultados serão apresentados. CONCLUSÕES: As recomendações sobre rastreamento do câncer de mama pareceram pouco claras aos médicos. As respostas sobre atividades educativas mostraram-se algumas vezes conflitantes. As crenças e opiniões sobre rastreamento foram bastante positivas. Escassez de equipamentos e custo do exame foram identificados como obstáculos ao rastreamento do câncer de mama.OBJECTIVE: To identify the characteristics of physicians in the State of Goiás, Brazil, regarding patient management, beliefs, opinions and knowledge about breast cancer. MATERIALS END METHODS: A total of 592 questionnaires were mailed to gynecologists, mastologists and geriatricians. The survey covered the following main aspects: 1 - socio-demographic characteristics (sex, age, year of graduation

Modelling refrigerant distribution in microchannel evaporators

DEFF Research Database (Denmark)

Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

2009-01-01

of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...... out of the evaporator is kept constant. It is shown that the cooling capacity of the evaporator is reduced significantly, both in the case of unevenly distributed inlet quality and for the case of non-uniform airflow on the outside of the channels.......The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...

Alteraciones de la calidad de vida en mujeres con cáncer de mama al recibir quimioterapia

OpenAIRE

Castillo Hidalgo, Marina

2015-01-01

Introducción: La calidad de vida es „‟la suma de factores físicos, emocionales y sociales que contribuyen al bienestar de una persona. Implica que, para medir ésta, deben medirse todos y cada uno de los factores que la componen. ’’ Es fundamental estudiar y valorar la calidad de vida de las mujeres con cáncer de mama que se someten a quimioterapia, ya que, tras analizar los diferentes factores, nos permite saber cuál es el impacto y los efectos secundarios que les provoca tanto la enfermedad ...

Eulerian-Eulerian two-phase numerical simulation of nanofluid laminar forced convection in a microchannel

International Nuclear Information System (INIS)

Kalteh, Mohammad; Abbassi, Abbas; Saffar-Avval, Majid; Harting, Jens

2011-01-01

In this paper, laminar forced convection heat transfer of a copper-water nanofluid inside an isothermally heated microchannel is studied numerically. An Eulerian two-fluid model is considered to simulate the nanofluid flow inside the microchannel and the governing mass, momentum and energy equations for both phases are solved using the finite volume method. For the first time, the detailed study of the relative velocity and temperature of the phases are presented and it has been observed that the relative velocity and temperature between the phases is very small and negligible and the nanoparticle concentration distribution is uniform. However, the two-phase modeling results show higher heat transfer enhancement in comparison to the homogeneous single-phase model. Also, the heat transfer enhancement increases with increase in Reynolds number and nanoparticle volume concentration as well as with decrease in the nanoparticle diameter, while the pressure drop increases only slightly.

Method for producing components with internal architectures, such as micro-channel reactors, via diffusion bonding sheets

Science.gov (United States)

Alman, David E [Corvallis, OR; Wilson, Rick D [Corvallis, OR; Davis, Daniel L [Albany, OR

2011-03-08

This invention relates to a method for producing components with internal architectures, and more particularly, this invention relates to a method for producing structures with microchannels via the use of diffusion bonding of stacked laminates. Specifically, the method involves weakly bonding a stack of laminates forming internal voids and channels with a first generally low uniaxial pressure and first temperature such that bonding at least between the asperites of opposing laminates occurs and pores are isolated in interfacial contact areas, followed by a second generally higher isostatic pressure and second temperature for final bonding. The method thereby allows fabrication of micro-channel devices such as heat exchangers, recuperators, heat-pumps, chemical separators, chemical reactors, fuel processing units, and combustors without limitation on the fin aspect ratio.

X-ray focusing with Wolter microchannel plate optics

CERN Document Server

Price, G J; Beijersbergen, M W; Fraser, G W; Bavdaz, M; Boutot, J P; Fairbend, R; Flyckt, S O; Peacock, A; Tomaselli, E

2002-01-01

Square-pore microchannel plate (MCP) X-ray optics of the 'lobster-eye' geometry have frequently been described in the literature. We have now investigated the use of a radial channel packing geometry which, in the context of an MCP pair slumped to the correct radii of curvature, can form a conic approximation to the Wolter Type I grazing incidence X-ray optic. Such an optic can provide a large effective area with very low mass and may be ideally suited for use in applications such as planetary imaging X-ray fluorescence. We present here the results of X-ray illumination of the first such optic, fabricated by Photonis SAS, France.

Heater Chip with Different Microchannels Geometries for a Low Pressure Free Molecular Micro-Resistojet

NARCIS (Netherlands)

Cordeiro Guerrieri, D.; de Athayde Costa e Silva, M.; Zandbergen, B.T.C.; Cervone, A.

2016-01-01

This paper presents a dynamic system approach for the modeling of fluid flow in microchannels to be used in thrust control applications. A micro-resistojet fabricated using MEMS (Microelectromechanical Systems) technology has been selected for the analysis. The device operates by vaporizing a liquid

A Design of a PET Detector Using Micro-Channel Plate Photomultipliers with Transmission-Line Readout.

Science.gov (United States)

Kim, H; Frisch, H; Chen, C-T; Genat, J-F; Tang, F; Moses, W W; Choong, W S; Kao, C-M

2010-01-01

A computer simulation study has been conducted to investigate the feasibility of a positron emission tomography (PET) detector design by using micro-channel plate (MCP) photomultiplier tubes (PMT) with transmission-line (TL) read-out and waveform sampling. The detector unit consisted of a 24×24 array of pixelated LSO crystals, each of which was 4×4×25 mm(3) in size, and two 102×102 mm(2) MCP-PMTs coupled to both sides of the scintillator array. The crystal (and TL) pitch was 4.25 mm and reflective medium was inserted between the crystals. The transport of the optical photons inside the scintillator were simulated by using the Geant4 package. The output pulses of the MCP-PMT/TL unit were formed by applying the measured single photo-electron response of the MCP-PMT/TL unit to each individual photon that interacts with the photo-cathode of the MCP-PMT. The waveforms of the pulses at both ends of the TL strips were measured and analyzed to produce energy and timing information for the detected event. An experimental setup was developed by employing a Photonis Planacon MCP-PMT (XP85022) and a prototype TL board for measuring the single photo-electron response of the MCP-PMT/TL. The simulation was validated by comparing the predicted output pulses to measurements obtained with a single MCP-PMT/TL coupled to an LSO crystal exposed to 511 keV gamma rays. The validated simulation was then used to investigate the performance of the proposed new detector design. Our simulation result indicates an energy resolution of ~11% at 511 keV. When using a 400-600 keV energy window, we obtain a coincidence timing resolution of ~323 ps FWHM and a coincidence detection efficiency of ~40% for normally-incident 511keV photons. For the positioning accuracy, it is determined by the pitch of the TLs (and crystals) in the direction normal to the TLs and measured to be ~2.5 mm in the direction parallel to the TLs. The energy and timing obtained at the front- and back-end of the scintillator

MAMOGRAFIA DE RASTREAMENTO PARA CÂNCER DE MAMA PELO SUS NA REGIÃO METROPOLITANA DO VALE DO PARAÍBA E LITORAL NORTE: TENDÊNCIA E CARACTERISTICAS SOCIAIS DE MULHERES SUBMETIDAS AO EXAME, ENTRE 2010 E 2014

OpenAIRE

Patricia Almeida Silva; Paula Vilhena Carnevale Vianna; Paulo Roxo Barja

2017-01-01

Análises da vulnerabilidade das mulheres para o câncer de mama revelam que, no Brasil, mulheres negras e menos instruídas têm menor acesso à mamografia de rastreamento, exame que permite a detecção precoce do câncer. Desde 2006, o controle do câncer de mama é política prioritária no SUS. Este estudo analisa a série histórica de exames de mamografia de rastreamento realizados pelo SUS no período de 2010 a 2014, na Região Metropolitana do Vale do Paraíba e Litoral Norte – RMVale, para investiga...

Enhancing heat transfer in microchannel heat sinks using converging flow passages

International Nuclear Information System (INIS)

Dehghan, Maziar; Daneshipour, Mahdi; Valipour, Mohammad Sadegh; Rafee, Roohollah; Saedodin, Seyfolah

2015-01-01

Highlights: • The fluid flow and conjugate heat transfer in microchannel heat sinks are studied. • The Poiseuille and Nusselt numbers are presented for width-tapered MCHS. • Converging walls are found to enhance the thermal performance of MCHS. • The optimum performance of MCHS for fixed inlet and outlet pressures is discussed. • For the optimum configuration, the pumping power is reduced up to 75%. - Abstract: Constrained fluid flow and conjugate heat transfer in microchannel heat sinks (MCHS) with converging channels are investigated using the finite volume method (FVM) in the laminar regime. The maximum pressure of the MCHS loop is assumed to be limited due to constructional or operational conditions. Results show that the Poiseuille number increases with increased tapering, while the required pumping power decreases. Meanwhile, the Nusselt number increases with tapering as well as the convection heat transfer coefficient. The MCHS having the optimum heat transfer performance is found to have a width-tapered ratio equal to 0.5. For this tapering configuration and at the maximum pressure constraint of 3000 Pa, the pumping power reduces by a factor of 4 while the overall heat removal rate is kept fixed in comparison with a straight channel

Slow waves in microchannel metal waveguides and application to particle acceleration

Directory of Open Access Journals (Sweden)

L. C. Steinhauer

2003-06-01

Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

Slow waves in microchannel metal waveguides and application to particle acceleration

Science.gov (United States)

Steinhauer, L. C.; Kimura, W. D.

2003-06-01

Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

Optimum thermal design of microchannel heat sink with triangular reentrant cavities

International Nuclear Information System (INIS)

Xia Guodong; Chai Lei; Wang Haiyan; Zhou Mingzheng; Cui Zhenzhen

2011-01-01

The effect of geometric parameters on water flow and heat transfer characteristics in microchannel heat sink with triangular reentrant cavities is numerically investigated. A three-dimensional laminar flow model, consisting of Navier-Stokes equations and energy conservation equation, with the conjugate heat transfer between the silicon base and water taken into consideration is solved numerically. In order to find the optimum geometric parameters, four variables, representing the distance and geometry of the triangular reentrant cavity, are designed. It is found that the vortices in the triangular reentrant cavities lead to chaotic advection and can greatly enhance the convective fluid mixing. The thermal and hydraulic boundary layers are interrupted and the repeated developing flow enhances heat transfer in the constant cross-section segment. Furthermore, the effects of the four design variables on heat transfer augmentation and pressure drop penalty are investigated depending on different Reynolds numbers by using the simulated annealing method. Based on the thermal enhancement factor performance maps, the optimal geometric parameters are obtained in principle. - Research highlights: → The microchannels with different triangular reentrant cavities are numerically investigated. → The heat transfer enhancement attributes to fluid mixing and redeveloped thermal boundary layers. → The optimal distance and geometry of the triangular reentrant cavity are obtained in principle.

Investigation of high frequency external perturbation effects on flow in a T-shape microchannel by μLIF technique

Science.gov (United States)

Kravtsova, A. Yu; Meshalkin, Yu E.; Bilsky, A. V.

2017-11-01

Investigation of high frequency external perturbation effect on flow inside T-shape microchannel was examined. In-phase pulsations of different frequencies were added to both inlets of the T-shaped microchannel to study mixing by means of Micro Laser Induced Fluorescence (μLIF) technique. For all flow regimes studied, mixing enhancement was obtained. Significant enhancement can be achieved at the beginning of the outlet channel operating in steady asymmetric regime (Re=186) by forcing at certain frequency ranges (f = 500Hz, f = 800Hz). Mixing suppression was also observed for two flow regimes (Re = 400, f = 1000Hz) and (Re = 120, f = 700Hz).

Aspectos técnicos da ressonância magnética de mama com meio de contraste: revisão da literatura Technical aspects of contrast-enhanced magnetic resonance imaging of the breast: literature review

Directory of Open Access Journals (Sweden)

Denise de Deus Leopoldino

2005-08-01

Full Text Available Com a difusão do uso de meios de contraste, avanços na tecnologia das bobinas de superfície e desenvolvimento de protocolos rápidos de aquisição de imagens, a ressonância magnética (RM de mama com meio de contraste tem-se mostrado importante modalidade na detecção, diagnóstico e estadiamento do câncer de mama. Apesar desses avanços, existem alguns pontos não consensuais no que diz respeito aos aspectos técnicos e critérios de interpretação de imagem da RM contrastada de mama. Neste artigo fazemos revisão bibliográfica dos parâmetros de interpretação de imagens e aspectos técnicos da RM de mama, incluindo considerações sobre a "performance" do equipamento, bobinas de radiofreqüência dedicadas, modo de utilização de contraste paramagnético, técnicas de supressão de gordura, planos de aquisição, seqüências de pulso e fontes de artefato.With the advances in surface coil technology and the development of new imaging protocols in addition to the increase of the use of contrast agents, contrast enhanced magnetic resonance imaging (MRI has emerged as a promising modality for detection, diagnosis and staging of breast cancer. Despite these advances, there are some unresolved issues, including no defined standard technique for contrast-enhanced breast MRI and no standard criteria of interpretation for the evaluation of such studies. In this article, we review the literature and discuss the general requirements and recommendations for contrast agent-enhanced breast MRI, including image interpretation criteria, MR equipment, dedicated radiofrequency coils, use of paramagnetic contrast agents, fat-suppression techniques, planes of acquisition, pulse sequence specifications and artifact sources.

Analgesia preventiva y multimodal con ketamina y dipirona en mastectomía radical por cáncer de mama

Directory of Open Access Journals (Sweden)

Miladys Justo Hernández

2015-11-01

Full Text Available El dolor agudo es frecuente en los pacientes que requieren intervención quirúrgica; su tratamiento satisfactorio es uno de los retos más importantes, presentando ventajas la terapéutica multimodal y preventiva. Se realizó un estudio longitudinal, prospectivo en 22 pacientes, a los que se les practicó mastectomía radical por cáncer de mama, con el objetivo de describir el uso de la analgesia multimodal y preventiva con ketalar y dipirona en el manejo del dolor posoperatorio de estos pacientes. La técnica anestésica utilizada fue total intravenosa, con propofol y fentanyl, dosis convencional. En el postoperatorio se vigiló la aparición de efectos colaterales. Los datos se colocaron en tablas de contingencia, procesados mediante el sistema de cálculos estadísticos que presenta Microsoft Excel. El análisis se realizó fundamentalmente a través de medidas de resúmenes, porcentaje y media aritmética. Se concluyó que la analgesia multimodal preventiva con ketamina y dipirona fue efectiva y segura en todos los casos, a los que se realizó radical de mama. Predominó el grupo de edad entre 46 y 65 años y ASA II. Las variables hemodinámicas y respiratorias se mantuvieron estables en todos los pacientes. No necesitaron analgesia de rescate. La somnolencia se manifestó en 13,6% de los casos.

Coaxial nozzle-assisted 3D bioprinting with built-in microchannels for nutrients delivery.

Science.gov (United States)

Gao, Qing; He, Yong; Fu, Jian-zhong; Liu, An; Ma, Liang

2015-08-01

This study offers a novel 3D bioprinting method based on hollow calcium alginate filaments by using a coaxial nozzle, in which high strength cell-laden hydrogel 3D structures with built-in microchannels can be fabricated by controlling the crosslinking time to realize fusion of adjacent hollow filaments. A 3D bioprinting system with a Z-shape platform was used to realize layer-by-layer fabrication of cell-laden hydrogel structures. Curving, straight, stretched or fractured filaments can be formed by changes to the filament extrusion speed or the platform movement speed. To print a 3D structure, we first adjusted the concentration and flow rate of the sodium alginate and calcium chloride solution in the crosslinking process to get partially crosslinked filaments. Next, a motorized XY stages with the coaxial nozzle attached was used to control adjacent hollow filament deposition in the precise location for fusion. Then the Z stage attached with a Z-shape platform moved down sequentially to print layers of structure. And the printing process always kept the top two layers fusing and the below layers solidifying. Finally, the Z stage moved down to keep the printed structure immersed in the CaCl2 solution for complete crosslinking. The mechanical properties of the resulting fused structures were investigated. High-strength structures can be formed using higher concentrations of sodium alginate solution with smaller distance between adjacent hollow filaments. In addition, cell viability of this method was investigated, and the findings show that the viability of L929 mouse fibroblasts in the hollow constructs was higher than that in alginate structures without built-in microchannels. Compared with other bioprinting methods, this study is an important technique to allow easy fabrication of lager-scale organs with built-in microchannels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heat Transfer and Pressure Drop Characteristics in Straight Microchannel of Printed Circuit Heat Exchangers

Directory of Open Access Journals (Sweden)

Jang-Won Seo

2015-05-01

Full Text Available Performance tests were carried out for a microchannel printed circuit heat exchanger (PCHE, which was fabricated with micro photo-etching and diffusion bonding technologies. The microchannel PCHE was tested for Reynolds numbers in the range of 100‒850 varying the hot-side inlet temperature between 40 °C–50 °C while keeping the cold-side temperature fixed at 20 °C. It was found that the average heat transfer rate and heat transfer performance of the countercurrrent configuration were 6.8% and 10%‒15% higher, respectively, than those of the parallel flow. The average heat transfer rate, heat transfer performance and pressure drop increased with increasing Reynolds number in all experiments. Increasing inlet temperature did not affect the heat transfer performance while it slightly decreased the pressure drop in the experimental range considered. Empirical correlations have been developed for the heat transfer coefficient and pressure drop factor as functions of the Reynolds number.

Performance enhancement of PV cells through micro-channel cooling

Directory of Open Access Journals (Sweden)

Muzaffar Ali

2015-11-01

Full Text Available Efficiency of a PV cell is strongly dependent on its surface temperature. The current study is focused to achieve maximum efficiency of PV cells even in scorching temperatures in hot climates like Pakistan where the cell surface temperatures can even rise up to around 80 ℃. The study includes both the CFD and real time experimental investigations of a solar panel using micro channel cooling. Initially, CFD analysis is performed by developing a 3D model of a Mono-Crystalline cell with micro-channels to analyze cell surface temperature distribution at different irradiance and water flow rates. Afterwards, an experimental setup is developed for performance investigations under the real conditions of an open climate of a Pakistan's city, Taxila. Two 35W panels are manufactured for the experiments; one is based on the standard manufacturing procedure while other cell is developed with 4mm thick aluminum sheet having micro-channels of cross-section of 1mm by 1mm. The whole setup also includes different sensors for the measurement of solar irradiance, cell power, surface temperature and water flow rates. The experimental results show that PV cell surface temperature drop of around 15 ℃ is achieved with power increment of around 14% at maximum applied water flow rate of 3 LPM. Additionally, a good agreement is also found between CFD and experimental results. Therefore, that study clearly shows that a significant performance improvement of PV cells can be achieved through the proposed cell cooling technique.

Ionizing device comprising a microchannel electron multiplier with secondary electron emission

International Nuclear Information System (INIS)

Chalmeton, Vincent.

1974-01-01

The present invention relates to a ionizing device comprising a microchannel electron multiplier involving secondary electron emission as a means of ionization. A system of electrodes is used to accelerate said electrons, ionize the gas and extract the ions from thus created plasma. Said ionizer is suitable for bombarding the target in neutron sources (target of the type of nickel molybdenum coated with tritiated titanium or with a tritium deuterium mixture) [fr

Experimental study on flame pattern formation and combustion completeness in a radial microchannel

Science.gov (United States)

Fan, Aiwu; Minaev, Sergey; Kumar, Sudarshan; Liu, Wei; Maruta, Kaoru

2007-12-01

Combustion behavior in a radial microchannel with a gap of 2.0 mm and a diameter of 50 mm was experimentally investigated. In order to simulate the heat recirculation, which is an essential strategy in microscale combustion devices, positive temperature gradients along the radial flow direction were given to the microchannel by an external heat source. A methane-air mixture was supplied from the center of the top plate through a 4.0 mm diameter delivery tube. A variety of flame patterns, including a stable circular flame and several unstable flame patterns termed unstable circular flame, single and double pelton-like flames, traveling flame and triple flame, were observed in the experiments. The regime diagram of all these flame patterns is presented in this paper. Some characteristics of the various flame patterns, such as the radii of stable and unstable circular flames, major combustion products and combustion efficiencies of all these flame patterns, were also investigated. Furthermore, the effect of the heat recirculation on combustion stability was studied by changing the wall temperature levels.

A novel ZVS high voltage power supply for micro-channel plate photomultiplier tubes

International Nuclear Information System (INIS)

Pei, Chengquan; Tian, Jinshou; Liu, Zhen; Qin, Hong; Wu, Shengli

2017-01-01

A novel resonant high voltage power supply (HVPS) with zero voltage switching (ZVS), to reduce the voltage stress on switching devices and improve conversion efficiency, is proposed. The proposed HVPS includes a drive circuit, a transformer, several voltage multiplying circuits, and a regulator circuit. The HVPS contains several secondary windings that can be precisely regulated. The proposed HVPS performed better than the traditional resistor voltage divider, which requires replacing matching resistors resulting in resistor dispersibility in the Micro-Channel Plate (MCP). The equivalent circuit of the proposed HVPS was established and the operational principle analyzed. The entire switching element can achieve ZVS, which was validated by a simulation and experiments. The properties of this HVPS were tested including minimum power loss (240 mW), maximum power loss (1 W) and conversion efficiency (85%). The results of this research are that the proposed HVPS was suitable for driving the micro-channel plate photomultiplier tube (MCP-PMT). It was therefore adopted to test the MCP-PMT, which will be used in Daya Bay reactor neutrino experiment II in China.

A novel ZVS high voltage power supply for micro-channel plate photomultiplier tubes

Energy Technology Data Exchange (ETDEWEB)

Pei, Chengquan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Tian, Jinshou [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Liu, Zhen [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Qin, Hong [School of Computer Science and Technology, Xi' an University of Science and Technology, Xi' an 710054 (China); Wu, Shengli, E-mail: slwu@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China)

2017-04-11

A novel resonant high voltage power supply (HVPS) with zero voltage switching (ZVS), to reduce the voltage stress on switching devices and improve conversion efficiency, is proposed. The proposed HVPS includes a drive circuit, a transformer, several voltage multiplying circuits, and a regulator circuit. The HVPS contains several secondary windings that can be precisely regulated. The proposed HVPS performed better than the traditional resistor voltage divider, which requires replacing matching resistors resulting in resistor dispersibility in the Micro-Channel Plate (MCP). The equivalent circuit of the proposed HVPS was established and the operational principle analyzed. The entire switching element can achieve ZVS, which was validated by a simulation and experiments. The properties of this HVPS were tested including minimum power loss (240 mW), maximum power loss (1 W) and conversion efficiency (85%). The results of this research are that the proposed HVPS was suitable for driving the micro-channel plate photomultiplier tube (MCP-PMT). It was therefore adopted to test the MCP-PMT, which will be used in Daya Bay reactor neutrino experiment II in China.

In-channel electrochemical detection in the middle of microchannel under high electric field.

Science.gov (United States)

Kang, Chung Mu; Joo, Segyeong; Bae, Je Hyun; Kim, Yang-Rae; Kim, Yongseong; Chung, Taek Dong

2012-01-17

We propose a new method for performing in-channel electrochemical detection under a high electric field using a polyelectrolytic gel salt bridge (PGSB) integrated in the middle of the electrophoretic separation channel. The finely tuned placement of a gold working electrode and the PGSB on an equipotential surface in the microchannel provided highly sensitive electrochemical detection without any deterioration in the separation efficiency or interference of the applied electric field. To assess the working principle, the open circuit potentials between gold working electrodes and the reference electrode at varying distances were measured in the microchannel under electrophoretic fields using an electrically isolated potentiostat. In addition, "in-channel" cyclic voltammetry confirmed the feasibility of electrochemical detection under various strengths of electric fields (∼400 V/cm). Effective separation on a microchip equipped with a PGSB under high electric fields was demonstrated for the electrochemical detection of biological compounds such as dopamine and catechol. The proposed "in-channel" electrochemical detection under a high electric field enables wider electrochemical detection applications in microchip electrophoresis.

Effect of Induced Magnetic Field on MHD Mixed Convection Flow in Vertical Microchannel

Science.gov (United States)

Jha, B. K.; Aina, B.

2017-08-01

The present work presents a theoretical investigation of an MHD mixed convection flow in a vertical microchannel formed by two electrically non-conducting infinite vertical parallel plates. The influence of an induced magnetic field arising due to motion of an electrically conducting fluid is taken into consideration. The governing equations of the motion are a set of simultaneous ordinary differential equations and their exact solutions in dimensionless form have been obtained for the velocity field, the induced magnetic field and the temperature field. The expressions for the induced current density and skin friction have also been obtained. The effects of various non-dimensional parameters such as rarefaction, fluid wall interaction, the Hartmann number and the magnetic Prandtl number on the velocity, the induced magnetic field, the temperature, the induced current density, and skin friction have been presented in a graphical form. It is found that the effect of the Hartmann number and magnetic Prandtl number on the induced current density is found to have a decreasing nature at the central region of the microchannel.

Static response of deformable microchannels

Science.gov (United States)

Christov, Ivan C.; Sidhore, Tanmay C.

2017-11-01

Microfluidic channels manufactured from PDMS are a key component of lab-on-a-chip devices. Experimentally, rectangular microchannels are found to deform into a non-rectangular cross-section due to fluid-structure interactions. Deformation affects the flow profile, which results in a nonlinear relationship between the volumetric flow rate and the pressure drop. We develop a framework, within the lubrication approximation (l >> w >> h), to self-consistently derive flow rate-pressure drop relations. Emphasis is placed on handling different types of elastic response: from pure plate-bending, to half-space deformation, to membrane stretching. The ``simplest'' model (Stokes flow in a 3D rectangular channel capped with a linearly elastic Kirchhoff-Love plate) agrees well with recent experiments. We also simulate the static response of such microfluidic channels under laminar flow conditions using ANSYSWorkbench. Simulations are calibrated using experimental flow rate-pressure drop data from the literature. The simulations provide highly resolved deformation profiles, which are difficult to measure experimentally. By comparing simulations, experiments and our theoretical models, we show good agreement in many flow/deformation regimes, without any fitting parameters.

Simulation of Micro-Channel and Micro-Orifice Flow Using Lattice Boltzmann Method with Langmuir Slip Model

Directory of Open Access Journals (Sweden)

A. R. Rahmati

2016-12-01

Full Text Available Because of its kinetic nature and computational advantages, the Lattice Boltzmann method (LBM has been well accepted as a useful tool to simulate micro-scale flows. The slip boundary model plays a crucial role in the accuracy of solutions for micro-channel flow simulations. The most used slip boundary condition is the Maxwell slip model. The results of Maxwell slip model are affected by the accommodation coefficient significantly, but there is not an explicitly relationship between properties at wall and accommodation coefficient. In the present wok, Langmuir slip model is used beside LBM to simulate micro-channel and micro-orifice flows. Slip velocity and nonlinear pressure drop profiles are presented as two major effects in such flows. The results are in good agreement with existing results in the literature.

Process for making unsaturated hydrocarbons using microchannel process technology

Science.gov (United States)

Tonkovich, Anna Lee [Dublin, OH; Yuschak, Thomas [Lewis Center, OH; LaPlante, Timothy J [Columbus, OH; Rankin, Scott [Columbus, OH; Perry, Steven T [Galloway, OH; Fitzgerald, Sean Patrick [Columbus, OH; Simmons, Wayne W [Dublin, OH; Mazanec, Terry Daymo, Eric

2011-04-12

The disclosed invention relates to a process for converting a feed composition comprising one or more hydrocarbons to a product comprising one or more unsaturated hydrocarbons, the process comprising: flowing the feed composition and steam in contact with each other in a microchannel reactor at a temperature in the range from about 200.degree. C. to about 1200.degree. C. to convert the feed composition to the product, the process being characterized by the absence of catalyst for converting the one or more hydrocarbons to one or more unsaturated hydrocarbons. Hydrogen and/or oxygen may be combined with the feed composition and steam.

Regulating the Emission Spectrum of CsPbBr₃ from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor.

Science.gov (United States)

Tang, Yong; Lu, Hanguang; Rao, Longshi; Li, Zongtao; Ding, Xinrui; Yan, Caiman; Yu, Binhai

2018-03-02

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr₃ QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr₃ QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL) spectral shift of CsPbBr₃ QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr₃ QDs can be applied to light-emitting diodes (LEDs), photoelectric sensors, lasers, etc.

Automated and temperature-controlled micro-PIV measurements enabling long-term-stable microchannel acoustophoresis characterization

DEFF Research Database (Denmark)

Augustsson, Per; Barnkob, Rune; Wereley, Steven T.

2011-01-01

We present a platform for micro particle image velocimetry (μPIV), capable of carrying out full-channel, temperature-controlled, long-term-stable, and automated μPIV-measurement of microchannel acoustophoresis with uncertainties below 5% and a spatial resolution in the order of 20 μm. A method to...

Hydrodynamic shrinkage of liquid CO2 Taylor drops in a straight microchannel

Science.gov (United States)

Qin, Ning; Wen, John Z.; Ren, Carolyn L.

2018-03-01

Hydrodynamic shrinkage of liquid CO2 drops in water under a Taylor flow regime is studied using a straight microchannel (length/width ~100). A general form of a mathematical model of the solvent-side mass transfer coefficient (k s) is developed first. Based on formulations of the surface area (A) and the volume (V) of a general Taylor drop in a rectangular microchannel, a specific form of k s is derived. Drop length and speed are experimentally measured at three specified positions of the straight channel, namely, immediately after drop generation (position 1), the midpoint of the channel (position 2) and the end of the channel (position 3). The reductions of drop length (L x , x  =  1, 2, 3) from position 1 to 2 and down to 3 are used to quantify the drop shrinkage. Using the specific model, k s is calculated mainly based on L x and drop flowing time (t). Results show that smaller CO2 drops produced by lower flow rate ratios ({{Q}LC{{O2}}}/{{Q}{{H2}O}} ) are generally characterized by higher (nearly three times) k s and Sherwood numbers than those produced by higher {{Q}LC{{O2}}}/{{Q}{{H2}O}} , which is essentially attributed to the larger effective portion of the smaller drop contributing in the mass transfer under same levels of the flowing time and the surface-to-volume ratio (~104 m-1) of all drops. Based on calculated pressure drops of the segmented flow in microchannel, the Peng-Robinson equation of state and initial pressures of drops at the T-junction in experiments, overall pressure drop (ΔP t) in the straight channel as well as the resulted drop volume change are quantified. ΔP t from position 1-3 is by average 3.175 kPa with a ~1.6% standard error, which only leads to relative drop volume changes of 0.3‰ to 0.52‰.

Hydrodynamic shrinkage of liquid CO2 Taylor drops in a straight microchannel.

Science.gov (United States)

Qin, Ning; Wen, John; Ren, Carolyn L

2018-01-16

Hydrodynamic shrinkage of liquid CO2 drops in water under a Taylor flow regime is studied using a straight microchannel (length/width ~ 100). A general form of a mathematical model of the solvent-side mass transfer coefficient (ks) is developed first. Based on formulations of the surface area (A) and the volume (V) of a general Taylor drop in a rectangular microchannel, a specific form of ks is derived. Drop length and speed are experimentally measured at three specified positions of the straight channel, namely, immediately after drop generation (position 1), the midpoint of the channel (position 2) and the end of the channel (position 3). The reductions of drop length (Lx, x = 1, 2, 3) from position 1 to 2 and down to 3 are used to quantify the drop shrinkage. Using the specific model, ks is calculated mainly based on Lx and drop flowing time (t). Results show that smaller CO2 drops produced by lower flow rate ratios (QLCO2/QH2O) are generally characterized by higher (nearly three times) ks and Sherwood numbers than those produced by higher QLCO2/QH2O, which is essentially attributed to the larger effective portion of the smaller drop contributing in the mass transfer under same levels of the flowing time and the surface-to-volume ratio (~ 104 m-1) of all drops. Based on calculated pressure drops of the segmented flow in microchannel, the Peng-Robinson equation of state (EOS) and initial pressures of drops at the T-junction in experiments, overall pressure drop (ΔPt) in the straight channel as well as the resulted drop volume change are quantified. ΔPt from position 1 to 3 is by average 3.175 kPa with a ~1.6% standard error, which only leads to relative drop volume changes of 0.3‰ to 0.52‰. © 2018 IOP Publishing Ltd.

RACISMO PRESENTE NA ANIMAÇÃO “SCRUB ME MAMA WITH A BOGGIE BEAT” DE WALTER LANTZ (1941)

OpenAIRE

Julio Geraldo Carvalho de Jesus; Davi Alexandre Pistila

2017-01-01

As Animações são fontes interessantes de serem exploradas pela perspectiva histórica, uma vez que trazem questões impostas pelo contexto da produção e podem ser utilizadas como meio de transmitir conhecimentos e ideologias. O presente artigo faz uma reflexão acerca do tema do racismo nas animações dirigidas e produzidas por Walter Lantz, no ano de 1941, tomando como base o cartoon “Scrube Me Mama with a Boogie Beat”, distribuído pela Universal Studios, e reexibido no ano de 1948. Apesar do ra...

Measuring density and compressibility of white blood cells and prostate cancer cells by microchannel acoustophoresis

DEFF Research Database (Denmark)

Barnkob, Rune; Augustsson, Per; Magnusson, Cecilia

2011-01-01

We present a novel method for the determination of density and compressibility of individual particles and cells undergoing microchannel acoustophoresis in an arbitrary 2D acoustic field. Our method is a critical advancement within acoustophoretic separation of biological cells, as the ability to...

Microchannel laminated mass exchanger and method of making

Science.gov (United States)

Martin, Peter M.; Bennett, Wendy D.; Matson, Dean W.; Stewart, Donald C.; Drost, Monte K.; Wegeng, Robert S.; Perez, Joseph M.; Feng, Xiangdong; Liu, Jun

2000-01-01

The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

Tumor neuroendócrino primário de mama: relato de três casos e revisão de literatura Primary neuroendocrine carcinoma of the breast: case report and literature review

Directory of Open Access Journals (Sweden)

Mariana Novaes Pinheiro

2012-04-01

Full Text Available Os tumores neuroendócrinos primários de mama (TNPMs são incomuns e não há consenso quanto a tratamento e prognóstico. No presente trabalho, foram revisados os diagnósticos de 1.184 pacientes com câncer de mama atendidos no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP/USP, identificando três casos que preenchiam os critérios de TNPM, segundo classificação estabelecida pela Organização Mundial da Saúde (OMS em 2003. Foram avaliados os achados clinicopatológicos e imuno-histoquímicos e as terapias realizadas, buscando caracterizar os padrões histopatológicos e de comportamento distintos dos carcinomas convencionais de mama.Primary neuroendocrine breast carcinomas (NECs are uncommon. Moreover, there is no consensus as to its treatment and prognosis. In this study, the diagnoses of 1,184 cases of breast cancer treated at Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto/Universidade de São Paulo (HCFMRP/USP were reviewed. Three among them fulfilled the criteria for primary NEC according to the classification established by the World Health Organization (WHO in 2003. Clinicopathological, immunohistochemical features and treatments were assessed in order to characterize histopathological and distinct patterns of conventional breast carcinomas.

Achieving community-based postpartum follow up in eastern Uganda: the field experience from the MamaMiso Study on antenatal distribution of misoprostol

OpenAIRE

Ditai, James; Frye, Laura J.; Durocher, Jill; Byrne, Meagan E.; Ononge, Sam; Winikoff, Beverly; Weeks, Andrew D.

2017-01-01

Background Advance provision of misoprostol to women during antenatal care aims to achieve broader access to uterotonics for the prevention of postpartum hemorrhage. Studies of this community-based approach usually involve antenatal education as well as timely postpartum follow-up visits to confirm maternal and neonatal outcomes. The MamaMiso study in Mbale, Uganda sought to assess the feasibility of conducting follow-up visits in the postpartum period following advance provision of misoprost...

Prevenção de câncer de mama em mulheres idosas: uma revisão

OpenAIRE

Carvalho, Cecília Maria Resende Gonçalves de; Brito, Cleidiane Maria Sales de; Nery, Inez Sampaio; Figueiredo, Maria do Livramento Fortes

2009-01-01

Trata-se de um estudo de revisão bibliográfica nacional, que objetivou refletir sobre a prevenção do câncer de mama em idosas. Esta curiosidade surgiu a partir da constatação da transição demográfica brasileira e da evidente feminização da velhice, o que impõe demandas assistênciais específicas e integrais para este segmento populacional. Ressalta-se a necessidade de ampliar o conhecimento a cerca da problemática, bem como a superação do negligenciamento na prevenção desta patologia, especial...

Detailed measurements and shaping of gate profiles for microchannel-plate-based X-ray framing cameras

International Nuclear Information System (INIS)

Landen, O.L.; Hammel, B.A.; Bell, P.M.; Abare, A.; Bradley, D.K.; Univ. of Rochester, NY

1994-01-01

Gated, microchannel-plate-based (MCP) framing cameras are increasingly used worldwide for x-ray imaging of subnanosecond laser-plasma phenomena. Large dynamic range (> 1,000) measurements of gain profiles for gated microchannel plates (MCP) are presented. Temporal profiles are reconstructed for any point on the microstrip transmission line from data acquired over many shots with variable delay. No evidence for significant pulse distortion by voltage reflections at the ends of the microstrip is observed. The measured profiles compare well to predictions by a time-dependent discrete dynode model down to the 1% level. The calculations do overestimate the contrast further into the temporal wings. The role of electron transit time dispersion in limiting the minimum achievable gate duration is then investigated by using variable duration flattop gating pulses. A minimum gate duration of 50 ps is achieved with flattop gating, consistent with a fractional transit time spread of ∼ 15%

Leiomiossarcoma de Mama: Relato de caso Leiomyosarcoma of the Breast: A Case Report

Directory of Open Access Journals (Sweden)

Juliane Oliveira de Assis

2001-05-01

Full Text Available Relatamos um caso de neoplasia maligna de mama com diagnóstico de leiomiossarcoma. Esta rara neoplasia tem comportamento biológico menos agressivo que outros tipos de sarcomas; por isso, chamamos atenção para o correto diagnóstico e a necessidade de graduação do neoplasma para seguimento da paciente, que, em nosso caso, com 2 anos de seguimento apresenta-se sem recidiva da doença.We report a malignant case of breast neoplasm, with the diagnosis of leiomyosarcoma. This rare neoplasm has a less aggressive biological behavior than the other types of breast sarcomas. That is the reason why we emphasize the correct diagnosis, and the necessity of graduating the neoplasm, for the patient's best follow-up. In our case, after 2 years of follow-up the patient continued with no relapse of the disease.

High Throughput, High Yield Fabrication of High Quantum Efficiency Back-Illuminated Photon Counting, Far UV, UV, and Visible Detector Arrays

Science.gov (United States)

Nikzad, Shouleh; Hoenk, M. E.; Carver, A. G.; Jones, T. J.; Greer, F.; Hamden, E.; Goodsall, T.

2013-01-01

In this paper we discuss the high throughput end-to-end post fabrication processing of high performance delta-doped and superlattice-doped silicon imagers for UV, visible, and NIR applications. As an example, we present our results on far ultraviolet and ultraviolet quantum efficiency (QE) in a photon counting, detector array. We have improved the QE by nearly an order of magnitude over microchannel plates (MCPs) that are the state-of-the-art UV detectors for many NASA space missions as well as defense applications. These achievements are made possible by precision interface band engineering of Molecular Beam Epitaxy (MBE) and Atomic Layer Deposition (ALD).

COMPUTER PROGRAM FOR CALCULATION MICROCHANNEL HEAT EXCHANGERS FOR AIR CONDITIONING SYSTEMS

Directory of Open Access Journals (Sweden)

Olga V. Olshevska

2016-08-01

Full Text Available Creating a computer program to calculate microchannel air condensers to reduce design time and carrying out variant calculations. Software packages for thermophysical properties of the working substance and the coolant, the correlation equation for calculating heat transfer, aerodynamics and hydrodynamics, the thermodynamic equations for the irreversible losses and their minimization in the heat exchanger were used in the process of creating. Borland Delphi 7 is used for creating software package.

Fabrication and Characterization of Silicon Micro-Funnels and Tapered Micro-Channels for Stochastic Sensing Applications

Directory of Open Access Journals (Sweden)

Frances S. Ligler

2008-06-01

Full Text Available We present a simplified, highly reproducible process to fabricate arrays of tapered silicon micro-funnels and micro-channels using a single lithographic step with a silicon oxide (SiO2 hard mask on at a wafer scale. Two approaches were used for the fabrication. The first one involves a single wet anisotropic etch step in concentrated potassium hydroxide (KOH and the second one is a combined approach comprising Deep Reactive Ion Etch (DRIE followed by wet anisotropic etching. The etching is performed through a 500 mm thick silicon wafer, and the resulting structures are characterized by sharp tapered ends with a sub-micron cross-sectional area at the tip. We discuss the influence of various parameters involved in the fabrication such as the size and thickness variability of the substrate, dry and wet anisotropic etching conditions, the etchant composition, temperature, diffusion and micro-masking effects, the quality of the hard mask in the uniformity and reproducibility of the structures, and the importance of a complete removal of debris and precipitates. The presence of apertures at the tip of the structures is corroborated through current voltage measurements and by the translocation of DNA through the apertures. The relevance of the results obtained in this report is discussed in terms of the potential use of these structures for stochastic sensing.

Experimental investigation of the liquid volumetric mass transfer coefficient for upward gas-liquid two-phase flow in rectangular microchannels

Directory of Open Access Journals (Sweden)

X. Y. Ji

2010-12-01

Full Text Available The gas-liquid two-phase mass transfer process in microchannels is complicated due to the special dynamical characteristics. In this work, a novel method was explored to measure the liquid side volumetric mass transfer coefficient kLa. Pressure transducers were utilized to measure the pressure variation of upward gas-liquid two-phase flow in three vertical rectangular microchannels and the liquid side volumetric mass transfer coefficient kLa was calculated through the Pressure-Volume-Temperature correlation of the gas phase. Carbon dioxide-water, carbon dioxide-ethanol and carbon dioxide-n-propanol were used as working fluids, respectively. The dimensions of the microchannels were 40 µm×240 µm (depth×width, 100 µm×800 µm and 100 µm×2000 µm, respectively. Results showed that the channel diameter and the capillary number influence kLa remarkably and that the maximum value of kLa occurs in the annular flow regime. A new correlation of kLa was proposed based on the Sherwood number, Schmidt number and the capillary number. The predicted values of kLa agreed well with the experimental data.

Avaliação do tratamento cirúrgico nos pacientes com metástase vertebral secundária ao carcinoma de mama Evaluación del tratamiento quirúrgico en pacientes con metástasis vertebrales secundarias a carcinoma de mama Evaluation of surgical treatment of patients with vertebral metastasis secondary to breast carcinoma

Directory of Open Access Journals (Sweden)

Alex Veneziano Oliveira Junior

2012-09-01

Full Text Available OBJETIVO: Avaliar os resultados cirúrgicos dos pacientes com metástase vertebral secundária ao carcinoma de mama. MÉTODOS: Vinte e duas pacientes operadas com doença metastática vertebral secundária ao carcinoma de mama foram avaliadas no pré-operatório, pós-operatório imediato e depois de 1 mês e 6 meses do procedimento cirúrgico, usando a escala numérica da dor e o índice de incapacidade de Oswestry (ODI. RESULTADOS: As medidas para dor produziram valor de p de 0,0001 para a diferença entre o pré-operatório e o pós-operatório imediato, 0,0005 entre o pós-operatório imediato e 1 mês de pós-operatório, e 0,0908 entre 1 mês de pós-operatório e 6 meses de pós-operatório, portanto, encontram-se evidências de diferenças entre o pré-operatório e o pós-operatório imediato, assim como entre o pós-operatório imediato e após o 1º mês, mas não há tal evidência entre o 1º e o 6º mês de pós-operatório. Quanto ao ODI, a diferença foi significativa em todos os períodos. CONCLUSÃO: A cirurgia melhora a dor e diminui a incapacidade dos pacientes com doença metastática secundária ao carcinoma de mama.OBJETIVO: Evaluar los resultados quirúrgicos de los pacientes con metástasis vertebrales secundarias a carcinoma de mama. MÉTODOS: Veintidós pacientes operados con enfermedad metastásica espinal secundaria a carcinoma de mama fueron evaluadas antes de la cirugía, inmediatamente después de la operación y después de 1 mes y 6 meses de la cirugía, mediante la escala numérica del dolor y el índice de discapacidad de Oswestry. RESULTADOS: Las medidas para el dolor produjeron un valor de "p" de 0,0001 para la diferencia entre el pre y postoperatorio, 0,0005 entre el postoperatorio inmediato y un mes después de la operación, y 0,0908 entre 1 mes después de la cirugía y el postoperatorio de 6 meses, por lo tanto, son la evidencia de las diferencias entre el pre y postoperatorio, así como entre el

Low temperature catalytic combustion of propane over Pt-based catalyst with inverse opal microstructure in microchannel reactor

NARCIS (Netherlands)

Guan, G.; Zapf, R.; Kolb, G.A.; Men, Y.; Hessel, V.; Löwe, H.; Ye, J.; Zentel, R.

2007-01-01

novel Pt-based catalyst with highly regular, periodic inverse opal microstructure was fabricated in a microchannel reactor, and catalytic testing revealed excellent conversion and stable activity for propane combustion at low temperatures

Two-fluid mixing in a microchannel

International Nuclear Information System (INIS)

Liu Yingzheng; Kim, Byoung Jae; Sung, Hyung Jin

2004-01-01

A numerical study of the mixing of two fluids (pure water and a solution of glycerol in water) in a microchannel was carried out. By varying the glycerol content of the glycerol/water solution, the variation in mixing behavior with changes in the difference in the properties of the two fluids (e.g., viscosity, density and diffusivity) was investigated. The mixing phenomena were tested for three micromixers: a squarewave mixer, a three-dimensional serpentine mixer and a staggered herringbone mixer. The governing equations of continuity, momentum and solute mass fraction were solved numerically. To evaluate mixing performance, a criterion index of mixing uniformity was proposed. In the systems considered, the Reynolds number based on averaged properties was Re=1 and 10. For low Reynolds number (Re=1), the mixing performance varied inversely with mass fraction of glycerol due to the dominance of molecular diffusion. The mixing performance deteriorated due to a significant reduction in the residence time of the fluid inside the mixers

Simulation, Fabrication and Analysis of Silver Based Ascending Sinusoidal Microchannel (ASMC for Implant of Varicose Veins

Directory of Open Access Journals (Sweden)

Muhammad Javaid Afzal

2017-09-01

Full Text Available Bioengineered veins can benefit humans needing bypass surgery, dialysis, and now, in the treatment of varicose veins. The implant of this vein in varicose veins has significant advantages over the conventional treatment methods. Deep vein thrombosis (DVT, vein patch repair, pulmonary embolus, and tissue-damaging problems can be solved with this implant. Here, the authors have proposed biomedical microdevices as an alternative for varicose veins. MATLAB and ANSYS Fluent have been used for simulations of blood flow for bioengineered veins. The silver based microchannel has been fabricated by using a micromachining process. The dimensions of the silver substrates are 51 mm, 25 mm, and 1.1 mm, in length, width, and depth respectively. The dimensions of microchannels grooved in the substrates are 0.9 mm in width and depth. The boundary conditions for pressure and velocity were considered, from 1.0 kPa to 1.50 kPa, and 0.02 m/s to 0.07 m/s, respectively. These are the actual values of pressure and velocity in varicose veins. The flow rate of 5.843 (0.1 nL/s and velocity of 5.843 cm/s were determined at Reynolds number 164.88 in experimental testing. The graphs and results from simulations and experiments are in close agreement. These microchannels can be inserted into varicose veins as a replacement to maintain the excellent blood flow in human legs.

Pressure loss in two-phase flow through a microchannel rod bundle

International Nuclear Information System (INIS)

Smith, A.C.; Hamm, L.L.; Qureshi, Z.; Steeper, T.J.

1998-01-01

The purpose of the microchannel rod bundle two-phase flow test described here was to provide data for benchmarking safety analyses for the accelerator production of tritium (APT). The objective was to obtain pressure loss data for a typical accelerator target rod bundle over a wide range of two-phase flow conditions. The test rod bundle assembly was fabricated for single-phase pressure drop tests conducted at Los Alamos National Laboratory (LANL) and subsequently used for the two-phase flow testing described here. The results for a typical case are given. These results fall generally in the slug flow regime for the horizontal flow results of Fukano and Kariyasaki for a 1.0-mm circular channel. Fukano and Kariyasaki found that surface tension effects were dominant in the 1-mm channel and report no churn regime. The results were also compared with the flow regime maps given by Triplett et al. for flow in discrete microchannels. Triplett employed both circular and trapezoidal channels, the latter to approximate the rod bundle interstitial flow channel shape. It was found that the rod bundle flow fell across the slug-to-churn flow regime transition reported by Triplett. This is consistent with the expectation that cross flow among channels would result in turbulent mixing and would suppress the formation of large discrete bubbles

Continuous Size-Dependent Sorting of Ferromagnetic Nanoparticles in Laser-Ablated Microchannel

Directory of Open Access Journals (Sweden)

Yiqiang Fan

2016-01-01

Full Text Available This paper reports a low-cost method of continuous size-dependent sorting of magnetic nanoparticles in polymer-based microfluidic devices by magnetic force. A neodymium permanent magnet was used to generate a magnetic field perpendicular to the fluid flow direction. Firstly, FeNi3 magnetic nanoparticles were chemically synthesized with diameter ranges from 80 nm to 200 nm; then, the solution of magnetic nanoparticles and a buffer were passed through the microchannel in laminar flow; the magnetic nanoparticles were deflected from the flow direction under the applied magnetic field. Nanoparticles in the microchannel will move towards the direction of high-gradient magnetic fields, and the degree of deflection depends on their sizes; therefore, magnetic nanoparticles of different sizes can be separated and finally collected from different output ports. The proposed method offers a rapid and continuous approach of preparing magnetic nanoparticles with a narrow size distribution from an arbitrary particle size distribution. The proposed new method has many potential applications in bioanalysis field since magnetic nanoparticles are commonly used as solid support for biological entities such as DNA, RNA, virus, and protein. Other than the size sorting application of magnetic nanoparticles, this approach could also be used for the size sorting and separation of naturally magnetic cells, including blood cells and magnetotactic bacteria.

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

Science.gov (United States)

Tang, Yong; Lu, Hanguang; Rao, Longshi; Ding, Xinrui; Yan, Caiman; Yu, Binhai

2018-01-01

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL) spectral shift of CsPbBr3 QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr3 QDs can be applied to light-emitting diodes (LEDs), photoelectric sensors, lasers, etc. PMID:29498710

Factores pronósticos del cáncer de mama Prognostic factors of breast cancer

Directory of Open Access Journals (Sweden)

José María González Ortega

2011-03-01

Full Text Available Los factores pronósticos se deben diferenciar de los factores predictivos. Un factor pronóstico es cualquier medición utilizable en el momento de la cirugía que correlaciona con el intervalo libre de enfermedad o supervivencia global en ausencia de tratamiento adyuvante sistémico y como resultado es capaz de correlacionar con la historia natural de la enfermedad. En contraste, un factor predictivo es cualquier medición asociada con respuesta a un tratamiento dado. Entre los factores pronósticos del cáncer de mama existen factores clínicos, histológicos, biológicos, genéticos y psicosociales. En esta revisión de los factores pronósticos psicosociales ha quedado demostrado que el estrés y la depresión son factores pronósticos negativos en las pacientes con cáncer de mama. Se debe recordar que la evaluación de un solo parámetro pronóstico ayuda, pero no es útil para la gestión clínica y terapéutica de la paciente.The prognostic factors must to be differentiated of the predictive ones. A prognostic factor is any measurement used at moment of the surgery correlated with the free interval of disease or global survival in the absence of the systemic adjuvant treatment and as result is able to correlate with the natural history of the disease. In contrast, a predictive factor is any measurement associated with the response to a given treatment. Among the prognostic factors of the breast cancer are included the clinical, histological, biological, genetic and psychosocial factors. In present review of psychosocial prognostic factors has been demonstrated that the stress and the depression are negative prognostic factors in patients presenting with breast cancer. It is essential to remember that the assessment of just one prognostic parameter is a help but it is not useful to clinical and therapeutic management of the patient.

Design, fabrication, and characterization of a valveless magnetic travelling-wave micropump

International Nuclear Information System (INIS)

Yu, Huawei; Ye, Weixiang; Zhang, Wei; Yue, Zhao; Liu, Guohua

2015-01-01

In this paper, we propose a valveless magnetic micropump for lab-on-a-chip and microfluidic applications. The micropump, based on polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA), consists primarily of a saw-toothed microchannel, two substrates, and two integrated NdFeB permanent magnetic arrays. The travelling wave beneath the top wall of the elastic microchannel can be induced by the proper magnetic pole orientation arrangement of these magnetic arrays, and the liquid particles are then transported along with the travelling wave in the microchannel. Appropriate geometry of the saw-toothed microchannel was also studied for optimizing the performance of the micropump. Experimental characterization of the micropump has been performed in terms of the frequency response of the flow rate and backpressure. The results demonstrate that this micropump is capable of reliably generating a maximum flow rate of 342.4 μL min −1 and operating against a high backpressure of 1.67 kPa. (paper)

Thermal analysis of a multi-layer microchannel heat sink for cooling concentrator photovoltaic (CPV) cells

Science.gov (United States)

Siyabi, Idris Al; Shanks, Katie; Mallick, Tapas; Sundaram, Senthilarasu

2017-09-01

Concentrator Photovoltaic (CPV) technology is increasingly being considered as an alternative option for solar electricity generation. However, increasing the light concentration ratio could decrease the system output power due to the increase in the temperature of the cells. The performance of a multi-layer microchannel heat sink configuration was evaluated using numerical analysis. In this analysis, three dimensional incompressible laminar steady flow model was solved numerically. An electrical and thermal solar cell model was coupled for solar cell temperature and efficiency calculations. Thermal resistance, solar cell temperature and pumping power were used for the system efficiency evaluation. An increase in the number of microchannel layers exhibited the best overall performance in terms of the thermal resistance, solar cell temperature uniformity and pressure drop. The channel height and width has no effect on the solar cell maximum temperature. However, increasing channel height leads to a reduction in the pressure drop and hence less fluid pumping power.

Slow waves in microchannel metal waveguides and application to particle acceleration

OpenAIRE

L. C. Steinhauer; W. D. Kimura

2003-01-01

Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

Systematic studies of micro-channel plate PMTs

International Nuclear Information System (INIS)

Lehmann, A.; Britting, A.; Cowie, E.; Dodokhof, V.Kh.; Dueren, M.; Dutta, D.; Eyrich, W.; Foehl, K.; Glazier, D.I.; Hayrapetyan, A.; Hoek, M.; Hohler, R.; Kaiser, R.; Keri, T.; Koch, P.; Kroeck, B.; Lehmann, D.; Marton, J.; Merle, O.; Montgomery, R.

2011-01-01

DIRC Cherenkov detectors will be the main devices for π/K separation at the PANDA experiment at FAIR. Due to their advantageous properties in terms of time resolution and especially inside magnetic fields micro-channel plate photo multipliers (MCP-PMTs) are very attractive sensor candidates. In this paper we present the investigation of several types of multi-anode MCP-PMTs. The darkcount rate, the behavior inside a magnetic field of up to 2 T, the time resolution, the gain homogeneity and crosstalk of multi-pixel MCP-PMTs were found to be well suitable for the PANDA requirements. Even the rate capability of the latest models from Burle-Photonis and Hamamatsu is satisfactory. Although a big step forward was accomplished with these recently available MCP-PMTs, the lifetime is still not sufficient for the photon densities expected for the PANDA DIRCs.

In vivo click reaction between Tc-99m-labeled azadibenzocyclooctyne-MAMA and 2-nitroimidazole-azide for tumor hypoxia targeting.

Science.gov (United States)

Sun, Wenjing; Chu, Taiwei

2015-10-15

The bioactivity of nitroimidazole in Tc-99m-labeled 2-nitroimidazole, a traditional solid tumor hypoxia-imaging agent for single photon emission computed tomography (SPECT), is reduced by the presence of large ligand and metallic radionuclide, exhibiting lower tumor-to-nontumor ratios. In an effort to solve this general problem, a pretargeting strategy based on click chemistry (strain-promoted cyclooctyne-azide cycloaddition) was applied. The functional click synthons were synthesized as pretargeting components: an azide group linked to 2-nitroimidazole (2NIM-Az) serves for tumor hypoxia-targeting and azadibenzocyclooctyne conjugated with monoamine monoamide dithiol ligand (AM) functions as radiolabeling and binding group to azides in vivo. 2NIM-triazole-MAMA was obtained from in vitro click reaction with a reaction rate constant of 0.98M(-1)s(-1). AM and 2NIM-triazole-MAMA were radiolabeled with Tc-99m. The hypoxia-pretargeting biodistribution was studied in Kunming mice bearing S180 tumor; (99m)Tc-AM and (99m)Tc-triazole-2NIM were used as blank control and conventional control. Compared to the control groups, the pretargeting experiment exhibits the best radio-uptake and retention in tumor, with higher tumor-to-muscle and tumor-to-blood ratios (up to 8.55 and 1.44 at 8h post-(99m)Tc-complex-injection, respectively). To some extent, the pretargeting strategy protects the bioactivity of nitroimidazole and therefore provides an innovative approach for the development of tumor hypoxia-SPECT imaging agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Geometric screening of core/shell hydrogel microcapsules using a tapered microchannel with interdigitated electrodes.

Science.gov (United States)

Niu, Ye; Qi, Lin; Zhang, Fen; Zhao, Yi

2018-07-30

Core/shell hydrogel microcapsules attract increasing research attention due to their potentials in tissue engineering, food engineering, and drug delivery. Current approaches for generating core/shell hydrogel microcapsules suffer from large geometric variations. Geometrically defective core/shell microcapsules need to be removed before further use. High-throughput geometric characterization of such core/shell microcapsules is therefore necessary. In this work, a continuous-flow device was developed to measure the geometric properties of microcapsules with a hydrogel shell and an aqueous core. The microcapsules were pumped through a tapered microchannel patterned with an array of interdigitated microelectrodes. The geometric parameters (the shell thickness and the diameter) were derived from the displacement profiles of the microcapsules. The results show that this approach can successfully distinguish all unencapsulated microparticles. The geometric properties of core/shell microcapsules can be determined with high accuracy. The efficacy of this method was demonstrated through a drug releasing experiment where the optimization of the electrospray process based on geometric screening can lead to controlled and extended drug releasing profiles. This method does not require high-speed optical systems, simplifying the system configuration and making it an indeed miniaturized device. The throughput of up to 584 microcapsules per minute was achieved. This study provides a powerful tool for screening core/shell hydrogel microcapsules and is expected to facilitate the applications of these microcapsules in various fields. Copyright © 2018 Elsevier B.V. All rights reserved.

Imagem corporal de mulheres com câncer de mama: uma revisão sistemática da literatura Body image of women with breast cancer: a systematic review of literature

Directory of Open Access Journals (Sweden)

Daniela Barsotti Santos

2011-05-01

Full Text Available A mulher passa por um importante processo de reformulação da imagem corporal quando lida com o câncer de mama. Este artigo objetiva a compreensão da relação que o câncer de mama e seus tratamentos têm no processo de (reelaboração da imagem corporal das mulheres, visando assim ao fomento de subsídios para a formação e a capacitação de profissionais de saúde mais atentos à promoção da qualidade de vida delas. Foi realizada uma revisão sistemática da literatura de artigos científicos publicados entre 2004 e 2009 disponíveis em três bases de dado; 56 artigos foram revisados e agrupados em quatro categorias. Destacamos a necessidade de mais estudos que contemplem características socioculturais de mulheres com câncer de mama, sobre diferenças na (reelaboração da imagem corporal de mulheres jovens e de mulheres mais velhas, e de publicações brasileiras sobre a experiência pessoal e aspectos socioculturais específicos de mulheres com câncer de mama.Women experience a major process of reshaping their body image when they deal with breast cancer. This article seeks to understand the relationship that breast cancer and its treatment have in the process of (reconstruction of a woman's body image. The ultimate objective is to promote knowledge to train health professionals to become more aware of a woman's quality of life. A systematic review of the literature of scientific articles published between 2004 and 2009 available in three scientific databases was conducted and a total of 56 articles were reviewed and grouped into four thematic categories. There is a pressing need for further studies on the socio-cultural characteristics of women with breast cancer, the differences of (reconstruction of body image of young and older women, and Brazilian publications about the personal experience and socio-cultural context of women with breast cancer.

Ansiedade no período pré-operatório de cirurgias de mama: estudo comparativo entre pacientes com suspeita de câncer e a serem submetidas a procedimentos cirúrgicos estéticos Ansiedad en el período preoperatorio de cirugías de mama: estudio comparativo entre pacientes con sospecha de cáncer a ser sometidas a procedimientos quirúrgicos estéticos Preoperative anxiety in surgeries of the breast: a comparative study between patients with suspected breast cancer and that undergoing cosmetic surgery

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Maria Luiza Melo Alves; Adriana Jucá Pimentel; Álvaro Antônio Guaratini; José Álvaro Marques Marcolino; Judymara Lauzi Gozzani; Ligia Andrade da Silva Telles Mathias

2007-01-01

JUSTIFICATIVA E OBJETIVOS: A avaliação da ansiedade não faz parte da rotina da avaliação pré-anestésica (APA), o que faz com que situações especiais em que o estado emocional dos pacientes possa estar alterado, passem despercebidas pelo anestesiologista. Este estudo visou comparar, no momento da APA ambulatorial, fatores de risco, intensidade e prevalência de ansiedade em pacientes com suspeita de câncer de mama e a serem submetidas a procedimentos cirúrgicos estéticos de mama. MÉTODO: Após a...

International Classification of Functioning, Disability, and Health in women with breast cancer: a proposal for measurement instruments Clasificación Internacional de Funcionalidad, Incapacidad y Salud en mujeres con cáncer de mama: propuesta de instrumentos para medición Classificação Internacional de Funcionalidade, Incapacidade e Saúde em mulheres com câncer de mama: proposta de instrumentos para mensuração

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Rosalina Jorge Koifman

2013-06-01

Full Text Available The International Classification of Functioning, Disability, and Health (ICF aims at standardization, but its applicability requires consistent instruments. In Brazil, invasive therapeutic approaches are frequent, leading to functional alterations. The current study thus aimed to identify and discuss instruments capable of measuring ICF core set codes for breast cancer. The review included ICF studies in women with breast cancer diagnosis and studies with the objective of translating and validating instruments for the Brazilian population, and consistent with the codes. Review studies, systematic or not, were excluded. Eight instruments were selected, and the WHOQOL-Bref was the most comprehensive. The use of various instruments showed 19 coinciding codes, and the instruments as a whole covered 58 of the total of 81 codes. The use of multiple instruments is time-consuming, so new studies are needed to propose parsimonious tools capable of measuring functioning in women treated for breast cancer.La Clasificación Internacional de Funcionalidad, Incapacidad y Salud (CIF tiene por objetivo una normatización, sin embargo, su aplicabilidad requiere instrumentos compatibles. En Brasil, los enfoques terapéuticos invasivos son frecuentes, conduciendo a alteraciones funcionales. En este sentido, el presente estudio tiene por objetivo identificar y discutir los instrumentos capaces de medir los códigos del core set de la CIF para el cáncer de mama. Se incluyeron estudios de la CIF en mujeres con diagnóstico de cáncer de mama y estudios con el fin de traducir y validar instrumentos para la población brasileña, compatibles con los códigos. Los estudios de revisión sistemática o no referentes a la literatura relacionada se excluyeron. Se seleccionaron ocho instrumentos, siendo el WHOQOL-BREF el más englobador. Con el uso de varios instrumentos se observaron 19 códigos coincidentes, siendo contemplados 58 de un total de 81 códigos. La utilizaci

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

OpenAIRE

Yong Tang; Hanguang Lu; Longshi Rao; Zongtao Li; Xinrui Ding; Caiman Yan; Binhai Yu

2018-01-01

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing hal...

"Ay mama Inés", de Jorge Guzmán: Entre la crónica y el testimonio

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Renato Martínez

2016-03-01

Full Text Available La excelente novela de Guzmán se autodefine como crónica testimonial, sin embargo los géneros crónica y testimonio, pese a su similar contingencia histórica, tienen un signo retórico opuesto. La crónica con notorias excepciones -es eulógica y tiene propósitos fundacionales. El testimonio es, por el contrario, denunciatorio y subversivo. Ay mama Inés, encuentra existencia en un campo de fuerzas originado por la tensión entre un anverso cronicado y su reverso testimonial, y donde el primero termina desplazando al segundo. La consecuencia más importante del predominio de la crónica es el relato de Pedro de Valdivia como un héroe épico y trágico de grandes proporciones, mientras que su lado histórico, ideológico y social retrocede a un segundo lugar.   Guzman's excellent novel defines itself as a "testimonial chronicle", although genders such as "testimony" and "chronicle" are opposite rhetorical sings, despite similar historical contingencies. The chronicle, save excepcional cases, is eulogical and fulfills foundational purposes. Testimonial, on the contrary is denunciatory and subversive. "Ay Mama Ines" finds its literary existence from a tug-of-war between a chronicled anverse and a testimonial reverse, where the former ends by displacing the letter. The Most important consequence of the predomiance of the chronicle element is in the history of Pedro de Valdivia as an epic and tragic hero of great proportions whereas his historical, ideological and social sides are relegated to a second place.

Optimization of Dimples in Microchannel Heat Sink with Impinging Jets — Part A: Mathematical Model and the Influence of Dimple Radius

Science.gov (United States)

Ming, Tingzhen; Cai, Cunjin; Yang, Wei; Shen, Wenqing; Gan, Ting

2018-06-01

With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modern advanced cooling technologies. In this work, the combination of dimples, impinging jets and microchannel heat sink was proposed to improve the heat transfer performance on a cooling surface with a constant heat flux 500 W/cm2. A mathematical model was advanced for numerically analyzing the fluid flow and heat transfer characteristics of a microchannel heat sink with impinging jets and dimples (MHSIJD), and the velocity distribution, pressure drop, and thermal performance of MHSIJD were analyzed by varying the radii of dimples. The results showed that the combination of dimples and MHSIJ can achieve excellent heat transfer performance; for the MHSIJD model in this work, the maximum and average temperatures can be as low as 320 K and 305 K, respectively when mass flow rate is 30 g/s; when dimple radius is larger than 0.195 mm, both the heat transfer coefficient and the overall performance h/ΔP of MHSIJD are higher than those of MHSIJ.

Animal Protection in the Lands of Pacha Mama: The Insufficiency of the Proposed Law Organic Animal Welfare in Ecuador

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José Carlos Machado Júnior

2016-12-01

Full Text Available Considering that the Pacha Mama is subject of right in the Ecuadorian Constitution, this project analyzes the rights of animals in Ecuador according to its Civil Code and its proposal for the Animal Welfare Act. For comparison purposes the laws of other countries that recognize the sentience of animals are quoted. The conclusion is that despite the paradigm of the Andean constitutionalism, Equatorian animals are legally considered things, a reality that will not change if approved the Law of Animal Welfare. The deductive method is used with bibliographic research and analysis of foreign law.

Single-phase flow and flow boiling of water in horizontal rectangular microchannels

OpenAIRE

Mirmanto

2013-01-01

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The current study is part of a long term experimental project devoted to investigating single-phase flow pressure drop and heat transfer, flow boiling pressure drop and heat transfer, flow boiling instability and flow visualization of de-ionized water flow in microchannels. The experimental facility was first designed and constructed by S. Gedupudi (2009) and in the present study; ...

Factores asociados con el tratamiento oportuno de mujeres con cáncer de mama apoyadas por una organización no gubernamental en Bogotá

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Guillermo Sánchez

2015-12-01

Conclusiones. Según la literatura científica, el pronóstico de las mujeres con cáncer de mama se modifica cuando se accede de manera oportuna al tratamiento. En este grupo de mujeres de Bogotá se encontraron factores socioeconómicos que al parecer determinaron su acceso efectivo al tratamiento, lo que revelaría la existencia de ‘inequidades’ determinadas socialmente.

Polybrominated Diphenyl Ethers in Human Milk and Serum from the U.S. EPA MAMA Study: Modeled Predictions of Infant Exposure and Considerations for Risk Assessment

Science.gov (United States)

Marchitti, Satori A.; Fenton, Suzanne E.; Mendola, Pauline; Kenneke, John F.; Hines, Erin P.

2016-01-01

Background: Serum concentrations of polybrominated diphenyl ethers (PBDEs) in U.S. women are believed to be among the world’s highest; however, little information exists on the partitioning of PBDEs between serum and breast milk and how this may affect infant exposure. Objectives: Paired milk and serum samples were measured for PBDE concentrations in 34 women who participated in the U.S. EPA MAMA Study. Computational models for predicting milk PBDE concentrations from serum were evaluated. Methods: Samples were analyzed using gas chromatography isotope-dilution high-resolution mass spectrometry. Observed milk PBDE concentrations were compared with model predictions, and models were applied to NHANES serum data to predict milk PBDE concentrations and infant intakes for the U.S. population. Results: Serum and milk samples had detectable concentrations of most PBDEs. BDE-47 was found in the highest concentrations (median serum: 18.6; milk: 31.5 ng/g lipid) and BDE-28 had the highest milk:serum partitioning ratio (2.1 ± 0.2). No evidence of depuration was found. Models demonstrated high reliability and, as of 2007–2008, predicted U.S. milk concentrations of BDE-47, BDE-99, and BDE-100 appear to be declining but BDE-153 may be rising. Predicted infant intakes (ng/kg/day) were below threshold reference doses (RfDs) for BDE-99 and BDE-153 but above the suggested RfD for BDE-47. Conclusions: Concentrations and partitioning ratios of PBDEs in milk and serum from women in the U.S. EPA MAMA Study are presented for the first time; modeled predictions of milk PBDE concentrations using serum concentrations appear to be a valid method for estimating PBDE exposure in U.S. infants. Citation: Marchitti SA, Fenton SE, Mendola P, Kenneke JF, Hines EP. 2017. Polybrominated diphenyl ethers in human milk and serum from the U.S. EPA MAMA Study: modeled predictions of infant exposure and considerations for risk assessment. Environ Health Perspect 125:706–713; http://dx.doi.org/10

Features of two-phase flow in a microchannel of 0.05×20 mm

Science.gov (United States)

Ronshin, Fedor

2017-10-01

We have studied the two-phase flow in a microchannel with cross-section of 0.05×20 mm2. The following two-phase flow regimes have been registered: jet, bubble, stratified, annular, and churn ones. The main features of flow regimes in this channel such as formation of liquid droplets in all two-phase flows have been distinguished.

Bubble splitting under gas–liquid–liquid three-phase flow in a double T-junction microchannel

NARCIS (Netherlands)

Liu, Yanyan; Yue, Jun; Zhao, Shuainan; Yao, Chaoqun; Chen, Guangwen

Gas–aqueous liquid–oil three-phase flow was generated in a microchannel with a double T-junction. Under the squeezing of the dispersed aqueous phase at the second T-junction (T2), the splitting of bubbles generated from the first T-junction (T1) was investigated. During the bubble splitting process,

Laser-Induced Motion of a Nanofluid in a Micro-Channel

OpenAIRE

Tran X. Phuoc; Mehrdad Massoudi; Ping Wang

2016-01-01

Since a photon carries both energy and momentum, when it interacts with a particle, photon-particle energy and momentum transfer occur, resulting in mechanical forces acting on the particle. In this paper we report our theoretical study on the use of a laser beam to manipulate and control the flow of nanofluids in a micro-channel. We calculate the velocity induced by a laser beam for TiO2, Fe2O3, Al2O3 MgO, and SiO2 nanoparticles with water as the base fluid. The particle diameter is 50 nm an...