779 research outputs found
In vitro analysis of the invasive phenotype of SUM 149, an inflammatory breast cancer cell line
BACKGROUND: Inflammatory breast cancer (IBC) is the most lethal form of locally invasive breast cancer known. However, very little information is available on the cellular mechanisms responsible for manifestation of the IBC phenotype. To understand the unique phenotype of IBC, we compared the motile and adhesive interactions of an IBC cell line, SUM 149, to the non-IBC cell line SUM 102. RESULTS: Our results demonstrate that both IBC and non-IBC cell lines exhibit similar adhesive properties to basal lamina, but SUM 149 showed a marked increase in adhesion to collagen I. In vitro haptotaxis assays demonstrate that SUM 149 was less invasive, while wound healing assays show a less in vitro migratory phenotype for SUM 149 cells relative to SUM 102 cells. We also demonstrate a role for Rho and E-cadherin in the unique invasive phenotype of IBC. Immunoblotting reveals higher E-cadherin and RhoA expression in the IBC cell line but similar RhoC expression. Rhodamine phalloidin staining demonstrates increased formation of actin stress fibers and larger focal adhesions in SUM 149 relative to the SUM 102 cell line. CONCLUSION: The observed unique actin and cellular architecture as well as the invasive and adhesive responses to the extracellular matrix of SUM 149 IBC cells suggest that the preference of IBC cells for connective tissue, possibly a mediator important for the vasculogenic mimicry via tubulogenesis seen in IBC pathological specimens. Overexpression of E-cadherin and RhoA may contribute to passive dissemination of IBC by promoting cell-cell adhesion and actin cytoskeletal structures that maintain tissue integrity. Therefore, we believe that these findings indicate a passive metastatic mechanism by which IBC cells invade the circulatory system as tumor emboli rather than by active migratory mechanisms
Design, performance, and applications of a coherent ultra-wideband random noise radar
A novel coherent ultra-wideband radar system operating in the 1- to 2-GHz frequency range has been developed recently at the University of Nebraska. The radar system transmits white Gaussian noise. Detection and localization of buried objects is accomplished by correlating the reflected waveform with a time-delayed replica of the transmitted waveform. Broadband dual-polarized log-periodic antennas are used for transmission and reception. A unique signal-processing scheme is used to inject coherence into the system by frequency translation of the ultrawideband signal by a coherent 160-MHz phase-locked source prior to performing heterodyne correlation. The system coherence allows the extraction of a target’s polarimetric amplitude and phase characteristics. This paper describes the unique design features of the radar system, develops the theoretical foundations of noise polarimetry, provides experimental evidence of the polarimetric and resolution capabilities of the system, and demonstrates results obtained in subsurface probing applications
Harmonisation of demographic and socio-economic variables in cross-national survey research
The aim of the present paper is to demonstrate how demographic and socio-economic variables in cross-national comparative survey research can be harmonized. After a short introduction discussing the difference between translation and harmonization, the path from a national concept and structure to an internationally-applicable measurement instrument is traced using the education variable as an example. Tables, References. Adapted from the source document. (author's abstract
Mixotrophic ciliate dynamics in two zones of a temperate and highly turbid estuary in South America, Argentina
La mixotrofía es una estrategia de alimentación por medio de la cual un organismo combina la autotrofia y la heterotrofia. La dinámica estacional de cinco ciliados mixótrofos comúnmente presentes en las aguas superficiales de la zona interna y media del estuario de Bahía Blanca, Argentina, rico en nutrientes, somero y con alta turbidez, se estudió mensualmente desde enero a diciembre de 2009. Se registraron los valores de temperatura, salinidad, turbidez y clorofila a, así como también la abundancia y biomasa de Strombidium capitatum, Strombidium acutum, Cyrtostrombidium sp., Lohmanniella oviformis y Tontonia appendiculariformis. La abundancia más alta de los mixótrofos se registró en el invierno en la zona interna, mientras que en la zona media del estuario la presencia de estos ciliados fue casi nula. La contribución más alta de clorofila proveniente de los mixótrofos a la clorofila a total fue 6% en la zona interna y 23% en la zona media (ambas estimaciones registradas en otoño). La baja abundancia de mixótrofos en la zona media del estuario durante el invierno, como usualmente es observado en otros sistemas costeros, podría ser explicada por una presión de pastoreo elevada en esta zona (control de tipo “top-down”) por parte de mesozooplancton (e.g., copépodos), en comparación con la zona interna. La floración secundaria del fitoplancton observada durante los últimos veranos, dominada por diatomeas de pequeño tamaño y fitoflagelados del nanoplancton, podría haber sustentado la alta abundancia de ciliados mixótrofos que se registró en la zona media en otoño y verano.Mixotrophy is a feeding strategy by which some organisms combine autrotrophic and heterotrophic activities. The seasonal dynamics of the five most common mixotrophic ciliates were studied monthly in surface layers of the inner and middle zone of the Bahía Blanca estuary, a nutrient-rich, shallow and highly turbid environment in Argentina, from January to December 2009. Temperature, salinity, turbidity and chlorophyll a were recorded, as well as the abundance and biomass of Strombidium capitatum, Strombidium acutum, Cyrtostrombidium sp., Lohmanniella oviformis and Tontonia appendiculariformis. The highest mixotrophic ciliate abundance was recorded during the austral winter (June-July) in the inner zone, meanwhile in the middle zone of the estuary the presence of these ciliates was almost null. The highest chlorophyll contribution derived from mixotrophic ciliates to total chlorophyll a ranged from 6% in the inner zone to 23% in the middle zone, both registered in autumn. The low abundance of mixotrophs in the middle zone of the estuary during the winter, as is usually observed in other coastal ecosystems, could be explained through a higher grazing pressure in this zone (top-down control) by mesozooplankton (e.g., copepods) in comparison to the inner zone. The secondary bloom of phytoplankton consistently observed during the last summers dominated by small sized diatoms and nanoplankton phytoflagelates, could have sustained the high abundance of mixotrophic ciliates registered in the middle zone in autumn and summer
Laser modulated optical reflectance of thin semiconductor films on glass
Semiconductor films, deposited by reactive magnetron sputtering on glass substrates have been analyzed with the help of laser-modulated optical reflectance. The results are discussed with respect to the thermal and charge carrier transport properties. Semiconductor properties have been identified both for micro-crystalline and amorphous film
Hidrografía de la columna de agua en Puerto Cuatreros
Se analizó la variación de las condiciones hidrográficas en la columna de agua en relación al ciclo de mareas en Puerto Cuatreros. Durante el período comprendido entre diciembre de 2004 y diciembre de 2005 se midieron perfiles verticales de temperatura y salinidad y se obtuvieron muestras de agua en dos profundidades para determinar la concentración de sedimentos en suspensión. Los parámetros meteorológicos y la marea se obtuvieron en forma continua. La temperatura del agua presentó un suave gradiente vertical en bajamar, en tanto que en pleamar el sistema se homogeneizó producto de la mezcla turbulenta de la marea. La temperatura superficial del agua presentó una variación a lo largo del ciclo de marea con mayor amplitud en los meses cálidos. La salinidad presentó un notorio gradiente vertical en bajamar. En creciente y pleamar la salinidad fue similar a la de la plataforma continental interior, mientras que en bajante y bajamar disminuyó por influencia de la descarga de agua dulce de arroyos próximos a la zona. En meses con altas precipitaciones la salinidad decreció significativamente y en días con altas temperaturas aumentó por efecto de la evaporación. Las mayores concentraciones de sedimento en suspensión se registraron con precipitaciones máximas y en marea bajante. Si bien la marea es el principal agente que influye sobre las características de la columna de agua, el factor meteorológico contribuye a generar variabilidad sobre las características hidrográficas en Puerto Cuatreros.The variation ofthe hydrographic conditions in the water column in relation to the tidal cycle in Cuatreros Port wás analyzed. Vertical profiles of temperature and salinity were measured between December 2004 and December 2005. Water samples were also obtained to determine the suspended sediment concentration. Meteorological parameters and tides were registered continuously. Water temperature showed a smooth vertical gradient during low tide, while in high tide the system became homogenous as a consequence of tidal mixing. The surface water temperature showed a variation throughout the tidal cycle with the greatest amplitude in the warm months. The salinity showed a significant vertical gradient in low tide. During flood and high tide salinity was similar to the typical values ofthe inner continental shelf, while in ebb and low tide it diminished because ofthe influence offreshwater discharges ofnearby streams. In months with high precipitations, salinity decreased significantly and in days with high temperatures it increased by effect ofevaporation. The highest concentrations ofsuspended sediment were registered with maximum precipitations and during ebb tide. Although the tide is the main agent that influences the characteristics ofthe water column, the meteorological factor contributes to generate variability on the hydrographic conditions in Cuatreros Port.Material digitalizado en SEDICI gracias a la colaboración de la Facultad de Ciencias Astronómicas y Geofísicas (UNLP).Asociación Argentina de Geofísicos y Geodesta
Code of conduct for scientific integrity
The scientific landscape has changed considerably since the Swiss Academies of Arts and Sciences published Integrity in scientific research: Principles and procedures in 2008. Consequently, an expert group was set up with members from the Swiss Academies of Arts and Sciences, the Swiss National Science Foundation, swissuniversities, and Innosuisse to review the changes that have taken place in recent years and to draw up this Code of conduct for scientific integrity. This Code is aimed at everyone involved in the generation, dissemination, and advancement of knowledge within the Swiss higher education system. This includes scientists, institutions, and funding organisations. Institutions and funding organisations have a special role to play in creating and maintaining the conditions in which scientific integrity can thrive. Scientific integrity is based on the observance of fundamental principles and their many different contextual concretisations. These principles guide scien- tists in their research and teaching and help them to deal with the practical, ethical, and intellectual challenges they can expect to encounter. The aim of this code of conduct is to promote appropriate attitudes and to help build a robust culture of scientific integrity that will stand the test of time. Ethical scientific behaviour rests on the basic principles of reliability, honesty, respect, and accountability and supports the concretisations of these basic principles within a specific frame of reference. This Code is intended to be a dynamic document. Its aim is to strengthen scientific integrity in all avenues of research and education, with a particular emphasis on the training and development of young people. Another of its aims is to establish a culture of research integrity in the scientific community, with the Code providing a welcome framework rather than imposing its own set of rules. It promotes common understanding and parity of treatment in dealing with violations of scientific integrity within and between institutions. The Code also considers current developments in the fields of Open Science and social media, and it examines the issue of time limitation from several points of view. In addition, it offers practical recommendations on how to set up an organisation for the protection of scientific integrity and describes the processes involved
Comparative analysis of selected exhaled breath biomarkers obtained with two different temperature-controlled devices
<p>Abstract</p> <p>Background</p> <p>The collection of exhaled breath condensate (EBC) is a suitable and non-invasive method for evaluation of airway inflammation. Several studies indicate that the composition of the condensate and the recovery of biomarkers are affected by physical characteristics of the condensing device and collecting circumstances. Additionally, there is an apparent influence of the condensing temperature, and often the level of detection of the assay is a limiting factor. The ECoScreen2 device is a new, partly single-use disposable system designed for studying different lung compartments.</p> <p>Methods</p> <p>EBC samples were collected from 16 healthy non-smokers by using the two commercially available devices ECoScreen2 and ECoScreen at a controlled temperature of -20°C. EBC volume, pH, NOx, LTB<sub>4</sub>, PGE<sub>2</sub>, 8-isoprostane and cys-LTs were determined.</p> <p>Results</p> <p>EBC collected with ECoScreen2 was less acidic compared to ECoScreen. ECoScreen2 was superior concerning condensate volume and detection of biomarkers, as more samples were above the detection limit (LTB<sub>4 </sub>and PGE<sub>2</sub>) or showed higher concentrations (8-isoprostane). However, NOx was detected only in EBC sampled by ECoScreen.</p> <p>Conclusion</p> <p>ECoScreen2 in combination with mediator specific enzyme immunoassays may be suitable for measurement of different biomarkers. Using this equipment, patterns of markers can be assessed that are likely to reflect the complex pathophysiological processes in inflammatory respiratory disease.</p
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