1,721,491 research outputs found
Characterisation of oxygen permeation into a microfluidic device for cell culture by in-situ NMR spectroscopy
No full textA compact microfludic device for perfusion culture of mammalian cells under in-situ metabolomic observation by NMR spectroscopy is presented. The chip is made from poly(methylmethacrylate) (PMMA), and uses a poly(dimethyl siloxane) (PDMS) membrane to allow gas exchange. It is integrated with a generic micro-NMR detector developed recently in our group [J. Magn. Reson. 262, 73-80 2016]. While PMMA is an excellent material in the context of NMR, PDMS is known to produce strong background signals. To mitigate this, the device keeps the PDMS away from the detection area. The oxygen permeation into the device is quantified using a flow chemistry approach. A solution of glucose is mixed on the chip with one of glucose oxidase, before flowing through the gas exchanger. The resulting concentration of gluconate is measured by 1H NMR spectroscopy as a function of flow rate. An oxygen equilibration rate constant of 2.4 s -1 is found for the device, easily sufficient to maintain normoxic conditions in a cell culture at modest perfusion flow rates
Learning social studies via objects in museums: investigation into Turkish elementary school students' lived experiences
No full textBased on a descriptive phenomenological research design, this study investigated Turkish elementary school students' experiences in learning social studies via objects in museums. After students visited four different museums during the teaching of three thematic units at sixth grade level, their lived experiences were elicited. Purposeful sampling was used to select the research participants and interviews were employed to gather data. The research data were analyzed by means of Giorgi's descriptive phenomenological framework, which helped reveal the structure of the phenomenon of learning social studies in museums. It was found that the essence of learning social studies via objects in museums consisted of five components. These were (1) excitement and motivation to learn about the past, (2) active participation in the learning process, (3) reconstruction of historical knowledge with the development of historical thinking skills, (4) enjoying social studies learning, and (5) heightened interest in social studies and seeing it as a valuable school subject. It was also found that some students had difficulties or negative learning experiences in their museum visits, such as difficulty in asking object-based questions or making comments on objects and relating them to the lessons being studied in the class. Because only a few students mentioned these difficulties, they were not included in the essence of the lived experience of learning social studies via objects in museums
An optimised detector for in-situ high-resolution NMR in microfluidic devices
Full text linkIntegration of high-resolution nuclear magnetic resonance (NMR) spectroscopy with microfluidic lab-on-a-chip devices is challenging due to limited sensitivity and line broadening caused by magnetic susceptibility inhomogeneities. We present a novel double-stripline NMR probe head that accommodates planar microfluidic devices, and obtains the NMR spectrum from a rectangular sample chamber on the chip with a volume of 2 ??l. Finite element analysis was used to jointly optimise the detector and sample volume geometry for sensitivity and RF homogeneity. A prototype of the optimised design has been built, and its properties have been characterised experimentally. The performance in terms of sensitivity and RF homogeneity closely agrees with the numerical predictions. The system reaches a mass limit of detection of 1.57 nmol View the MathML sources, comparing very favourably with other micro-NMR systems. The spectral resolution of this chip/probe system is better than 1.75 Hz at a magnetic field of 7 T, with excellent line shape
Performance Study of A Time-Of-Flight Method Used For Cosmic Ray Detection
No full textYilmaz, Ali/0000-0001-5963-8306WOS: 000486396800004Time-of-Flight methods have been rapidly developed and recently used in many experiments for determination of particle direction, identification of particles and energy resolutions. This paper describes a method of time-mark determination on the reconstruction algorithm, based on the sampled signal, used for time-of-flight measurements. This method was developed for distinguishing the signals which were received from scintillator detector with a silicon photomultiplier readout developed for a cosmic ray counter telescope by fitting to pulse shape. The method was verified using experimental data taken in the location 40 degrees 54'52 '' N and 38 degrees 19'26 '' E with the elevation of 30 m above the sea level. The data samples were acquired by the counters which have a scintillator with dimensions of 20 x 20 x 1.4 cm(3), optically coupled from one side to silicon photomultiplier, then the signals read out by fast sampling digitizer board Domino Ring Sampler board version 4. The method can reconstruct each pulse even for multiple events without losing the count within the small time window. Using this method, 4.969 ns time-of-flight value was established and the rise times for scintillation counters, named Tile 1 and Tile 2, were measured to be about 6.27 +/- 0.16 ns and 4.979 +/- 0.165 ns, respectively
Electron-muon identification by atmospheric shower and electron beam in a new eas detector concept
No full textWe present results demonstrating the time resolution and μ/e separation capabilities of a new concept
for an EAS detector capable of measuring cosmic rays arriving with large zenith angles. This kind of detector has been
designed to be part of a large area (several square kilometer) surface array designed to measure ultra high energy
(10–200 PeV)τ neutrinos using the Earth-skimming technique. A criterion to identify electron-gammas is also
shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-
GRANDE experiment in Karlsruhe, Germany
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Figure 1 in Identification and molecular characterization of Otobius megnini (Ixodida: Argasidae) seen in humans in Muş province, Turkey
No full textFigure 1. PCR amplification of 16S rRNA gene region in Otobius megnini (Amplicon length 360 bp).Published as part of Karakuş, Ayşe, Yilmaz, Ali Bilgin, Karaca, Servet, Dik, Bilal & Denizhan, Vural, 2022, Identification and molecular characterization of Otobius megnini (Ixodida: Argasidae) seen in humans in Muş province, Turkey, pp. 145-152 in Persian Journal of Acarology 11 (1) on page 147, DOI: 10.22073/pja.v11i1.71113, http://zenodo.org/record/717348
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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