Search results for "x-ray"
showing 10 items of 4234 documents
Role of post mortem computed tomography in diagnosis of upper cervical fractures in child due to road accident: A case report and literature review
2019
The upper cervical spine has unique anatomical features that distinguish it from the remainder of the cervical spine. Its motion segments make up a large amount of total cervical spine motion and, as a result,predispose it to a unique set of injuries. Cervical spine trauma is a common problem with a wide range of severity from minor ligamentous injury to section of the spinal cord. The use of post mortem CT (PMCT), and the subsequent multi-planar and volume rendering reconstruction techniques can provide non-invasive, objective operator-independent imaging data set that may be further reviewed by other specialists. and can substantially add to forensic examinations of the skeleton, especial…
Microstructural evaluation and recommendations for face masks in community use to reduce the transmission of respiratory infectious diseases
2022
Funding Information: A.K., H.Y. and R.J. also acknowledges the funding through Academy of Finland BESIMAL (Decision No. 334197) and Aalto University, Department of Communications and Networking. This work has also received funding in part from the EPSRC UK (grant number EP/R012091/1). A.K. would also like to thank Mr. Volkan Kaplan for the fruitful discussions in the early concept generation. Publisher Copyright: © 2022 The Author(s) Background and Objective: Recommendations for the use of face masks to prevent and protect against the aerosols (≤5µm) and respiratory droplet particles (≥5µm), which can carry and transmit respiratory infections including severe acute respiratory syndrome coro…
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…
Quantitative microscopy reveals stepwise alteration of chromatin structure during herpesvirus infection
2019
During lytic herpes simplex virus 1 (HSV-1) infection, the expansion of the viral replication compartments leads to an enrichment of the host chromatin in the peripheral nucleoplasm. We have shown previously that HSV-1 infection induces the formation of channels through the compacted peripheral chromatin. Here, we used three-dimensional confocal and expansion microscopy, soft X-ray tomography, electron microscopy, and random walk simulations to analyze the kinetics of host chromatin redistribution and capsid localization relative to their egress site at the nuclear envelope. Our data demonstrated a gradual increase in chromatin marginalization, and the kinetics of chromatin smoothening arou…
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 …
Characterization of three-dimensional microstructure of composite materials by X-ray tomography
2016
Analysis methods for X-ray microtomographic images of short fibre composite materials were developed. The methods enable estimation of microstructural properties of the material, e.g., aspect ratio and orientation of fibres. Being based on X-ray microtomography and image analysis, the methods are nondestructive and do not require user intervention. In particular, a method for determination of the aspect ratio of fibres was first developed. The method contains an assumption about similarity of the shape of the fibres. The assumption was relaxed in an improved method that can estimate cross-sectional properties of fibres, too, e.g., cross-sectional area. Additionally, the effect of finite ima…
The Large Observatory For x-ray Timing
2014
The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supra-nuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m 2 effective area, 2-30 keV, 240 eV spectral resolution, 1 deg collimated field of view) and a WideFi…
High-rate x-ray spectroscopy in mammography with a CdTe detector: A digital pulse processing approach
2010
Purpose:Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate x-ray spectroscopy in mammography. Methods: The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the respon…
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…