Search results for "methods [Biological Assay]"
showing 10 items of 243 documents
The contribution of colour and spatial frequency cues to contour integration
2011
Beobachtungen nach einer neuen optischen Methode: ein Beitrag zur Experimental-Physik
1864
Inhalt: Princip der Beobachtungs-Methode... 2 Specielle Beschreibung des Apparates... 8 Bemerkungen über den Gebrauch und die Adjustirung... 13 Schlieren in Gläsern ... 16 Beobachtungen mittels des Schlieren-Apparates... 18 Veränderung durchsichtiger Körper durch Temperatur und Druck... 19 Diffusionsbewegungen... 21 Untersuchung der Flammen... 23 Beugungsphänomene... 26 Sichtbarmachung der Schallwellen... 27 Beobachtungen über den electrischen Funken... 29 Der Inductionsfunken... 35 Der Flaschenfunken... 42 Schlussbemerkungen... 49
Direct measurement of the melting temperature of supported DNA by electrochemical method
2003
The development of biosensors based on DNA hybridization requires a more precise knowledge of the thermodynamics of the hybridization at a solid interface. In particular, the selectivity of hybridization can be affected by a lot of parameters such as the single-strand (ss)DNA density, the pH, the ionic strength or the temperature. The melting temperature, T(m), is in part a function of the ionic strength and of the temperature and therefore provides a useful variable in the control of the selectivity and sensitivity of a DNA chip. The electrochemical technique has been used to determine the T(m) values when the probe is tethered by a DNA self-assembled monolayer (SAM). We have built a speci…
La distribuzione di Maxwell-Boltzmann: i risultati di una sperimentazione svolta nell'ambito dei corsi di laurea in ingegneria
2011
This paper describes the outcomes of an teaching experiment conducted in the seminar held at the Faculty Engineering of Palermo University. The theme of the seminar focused on undergraduate experiment that yields the velocity distribution of thermionic electrons by analyzing the I-V characteristics of diodes and triodes. By using a simple model, the velocity distribution of thermionic electrons emitted by the vacuum tube cathode can be described by Maxwell's distribution. The experiment allows students to focus on the distribution function more than on difficulties arising from the complexity of thermionic emission. Questo articolo descrive i risultati di una sperimentazione didattica condo…
A FRET-based assay for characterization of alternative splicing events using peptide nucleic acid fluorescence in situ hybridization
2009
We describe a quantitative method for detecting RNA alternative splicing variants that combines in situ hybridization of fluorescently labeled peptide nucleic acid (PNA) probes with confocal microscopy Förster resonance energy transfer (FRET). The use of PNA probes complementary to sequences flanking a given splice junction allows to specifically quantify, within the cell, the RNA isoform generating such splice junction by FRET measure. As a proof of concept we analyzed two alternative splicing events originating from lymphocyte antigen 6 (LY6) complex, locus G5B (LY6G5B) pre-mRNA. These are characterized by the removal of the first intron (Fully Spliced Isoform, FSI) or by retention of suc…
'School adopts an experiment': the magnetic levitation of superconductors
2010
The event 'School adopts an experiment' is an event targeted at high schools and secondary schools. It is based on a tight and direct collaboration between researchers and school students and teachers. Several schools were involved in the event by 'adopting' an experiment in physics research laboratories. Groups of selected students were first trained by university researchers, then they demonstrated the experiments to other students and teachers during the event. Students who adopted an experiment acquired knowledge of the subjects connected with the experiment in a most impressive way compared with the usual didactics at school. Further positive points were: (i) to establish a close and d…
'School adopts an experiment': the photoluminescence in extra-virgin olive oil and in tonic water
2011
We report a laboratory activity, carried out along with high- and secondary-school students, that can be done to increase the interest of the young in scientific studies. Groups of selected students ‘adopted’ experiments at physics research laboratories, under the guidance of university researchers. Subsequently, the students demonstrated the experiments to the public at large during the annual science festival organized in Palermo by the association PalermoScienza, in collaboration with the University of Palermo. Experiments on the magnetic levitation of superconductors and on the photoluminescence of several substances were proposed. We discuss the experiment on photoluminescence as a cas…
An inquiry-based approach to Maxwell distribution: a case study with engineering students
2013
The concept of distribution is a fundamental component of statistical thinking. This paper describes a teaching approach for it that uses a specific activity related to the field of statistical mechanics. The concept of the velocity distribution of a particle system is dealt with using an inquiry-based approach involving an experimental examination of Maxwell’s distribution. Some outcomes of a teaching experiment held at the Faculty of Engineering of the University of Palermo, Italy are described.
Search for pulsations at high radio frequencies from accreting millisecond X-ray pulsars in quiescence
2010
It is commonly believed that millisecond radio pulsars have been spun up by transfer of matter and angular momentum from a low-mass companion during an X-ray active mass transfer phase. A subclass of low-mass X-ray binaries is that of the accreting millisecond X-ray pulsars, transient systems that show periods of X-ray quiescence during which radio emission could switch on. The aim of this work is to search for millisecond pulsations from three accreting millisecond X-ray pulsars, XTE J1751-305, XTE J1814-338, and SAX J1808.4-3658, observed during their quiescent X-ray phases at high radio frequencies (5 - 8 GHz) in order to overcome the problem of the free-free absorption due to the matter…
On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras
2010
X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/dE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon "pile-up", wherein two or mor…