Search results for " Tom"

Radzenes epitēlija strukturālās izmaiņas mīksto kontaktlēcu lietotājiem

2021

Darbs ir uzrakstīts latviešu valodā uz 38 lapaspusēm. Tas satur 19 attēlus, 8 tabulas, 56 atsauces uz literatūras avotiem. Darba mērķis: noskaidrot mīksto kontaktlēcu ietekmi uz radzenes epitēlija biezuma kartējumu. Metode: 63 dalībniekiem (126 acis) vecumā no 18 līdz 44 gadiem tika iegūts radzenes epitēlija biezuma kartējums, veicot radzenes skenēšanu ar spektrālā domēna optiskās koherences tomogrāfu Maestro 3D (Topcon). Rezultāti: Pētījumā tika noskaidrots, ka visiem dalībniekiem radzenes epitēlijs ir biezāks centrā, un jaunākās paaudzes mīkstās kontaktlēcas nerada radzenes epitēlija biezuma izmaiņas, neatkarīgi no kontaktlēcu materiāla (hidrogēla / silikonhidrogēla) un valkāšanas modalit…

Soft X-ray Tomography Reveals HSV-1-Induced Remodeling of Human B Cells.

2022

Upon infection, viruses hijack the cell machinery and remodel host cell structures to utilize them for viral proliferation. Since viruses are about a thousand times smaller than their host cells, imaging virus-host interactions at high spatial resolution is like looking for a needle in a haystack. Scouting gross cellular changes with fluorescent microscopy is only possible for well-established viruses, where fluorescent tagging is developed. Soft X-ray tomography (SXT) offers 3D imaging of entire cells without the need for chemical fixation or labeling. Here, we use full-rotation SXT to visualize entire human B cells infected by the herpes simplex virus 1 (HSV-1). We have mapped the temporo…

X-ray tomographic method for measuring three-dimensional deformation and water content distribution in swelling clays

2015

A non-invasive method for simultaneous measurement of the 3D displacement field and the water content distribution of a wetted solid material is developed. The method is based on comparison of X-ray tomographic images of a material sample in the reference state and in the wetted and deformed state. The deformation and water content analyses were successfully compared with numerical results for a cylindrical rubber test sample under axial compression, and with gravimetric results from axially wetted and sliced cylindrical bentonite samples, respectively. The methods were applied in a 4D study (three spatial dimensions and time) of wetting and deformation of purified swelling bentonite doped …

Evaluation of biocidal potential of some plant species from the Mediterranean wild flora

Composition and corrosion phases of Etruscan Bronzes from Villanovan Age

2008

A neutron diffraction (ND) and neutron tomography (NT) study of laminated ancient bronzes was performed at the ISIS (Rutherford Appleton Laboratory, UK) neutron source and at the BENSC reactor (Hahn-Meitner Institut, Germany). The samples are part of an 8th century BC Etruscan collection discovered in the necropolises of Osteria-Poggio Mengarelli and Cavalupo in the Vulci area (Viterbo, Italy). The study allowed us to derive-in a totally non-destructive manner-information related to the main composition of the objects, possible presence of alterations and their nature, crusts and inclusions, as well as structure of the bulk. The presence of some components is linked to a variety of question…

Pore and mineral structure of rock using nano-tomographic imaging

2015

ABSTRACTIn order to better understand the micrometer-scale structure of rock and its transport properties which arise from it, seven monomineral samples from two sites (Olkiluoto and Sievi, Finland) were studied with micro- and nanotomography and scanning electron microscopy. From the veined gneiss of Olkiluoto we studied biotite, potassium feldspar, plagioclase (composition of oligoclase) and cordierite, and from Sievi tonalite biotite and two grains of plagioclase (albite). These minerals were the main minerals of these samples. Samples were carefully separated and selected using heavy liquid separation and stereomicroscopy, their three dimensional structure was imaged using X-ray tomogra…

3D virtual Histopathology of Cardiac Tissue from Covid-19 Patients based on Phase-Contrast X-ray Tomography

2021

X-ray phase-contrast tomography datasets of formalin fixed paraffin embedded unstained cardiac tissue from Covid-19 patients as well as from control tissue. For each group one overview scan of the entire biopsy (3.5mm cross section) from binning and stitching different tomograms (PB bin2, voxel size: 1.3µm) as well as the respective laboratory data (LJ, voxel size: 2µm, tissue masked) and a cone-beam zoom tomogram recorded with waveguide illumination (WG, voxel size: 159 nm) is uploaded. Further datasets can be provided on request. The data has been recorded at the institute for X-ray physics (Göttingen, Germany) and DESY at the GINIX instrument, beamline P10 of the PETRAII…

X-ray tomographic method for measuring 3D deformation and liquid content in swelling materials

2015

A non-invasive method for measuring the three-dimensional displacement field and liquid content distribution in a wetting and swelling material using X-ray tomographic imaging is introduced. The method is demonstrated here in monitoring the evolution of 3D deformation and water content distributions in cylindrical samples of swelling clay material wetted in a constant total volume. The measurements were carried out using a high-resolution microtomographic device (SkyScan 1172) and image voxel size 24 µm. The results obtained are repeatable and appear qualitatively correct and plausible. They are useful e.g. in validating models involving transport of water and the resulting deformation of s…

Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry

2021

Radiation-sensitive gels are among the most recent and promising developments for radiation therapy (RT) dosimetry. RT dosimetry has the twofold goal of ensuring the quality of the treatment and the radiation protection of the patient. Benchmark dosimetry for acceptance testing and commissioning of RT systems is still based on ionization chambers. However, even the smallest chambers cannot resolve the steep dose gradients of up to 30–50% per mm generated with the most advanced techniques. While a multitude of systems based, e.g., on luminescence, silicon diodes and radiochromic materials have been developed, they do not allow the truly continuous 3D dose measurements offered by radiation-se…

Educación para la sostenibilidad y educación ambiental

2010

En este trabajo se analizan algunos de los obstáculos que están dificultando la implicación de diferentes sectores sociales en la adopción de las medidas necesarias para hacer frente a la actual situación de emergencia planetaria. En particular, analizamos la supuesta confrontación entre educación ambiental y educación para la sostenibilidad. Intentaremos mostrar que no existen razones para dicho antagonismo, sino que responde a malentendidos que es urgente deshacer, porque entorpecen la necesaria convergencia de esfuerzos para lograr una formación ciudadana que haga comprender la gravedad de la situación y prepare para participar en la toma de decisiones. Dans cet article nous analysons qu…