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Seven-Pinhole Tomographic Reconstruction Algorithm
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
The first stage of the reconstruction algorithm prepares the three images (point source, flood, and patient) for processing. The point source image supplies the projected coordinates in each view of a point source placed at a known distance from the pinhole endplate. These coordinates are determined by a simple search algorithm. The approximate position of the point source coordinates are known from prior acquisitions. Only a small region around the historically known point source coordinates, therefore, are searched for maxima to reduce computation time; the entire image need not be searched for these maxima. The point source coordinates are saved for each view and are used, as described later, to superpose mathematically the different views of the patient radionuclide distribution in forming the tomographic planes.
Small Sample Methods
Published in Ørnulf Borgan, Norman E. Breslow, Nilanjan Chatterjee, Mitchell H. Gail, Alastair Scott, Christopher J. Wild, Handbook of Statistical Methods for Case-Control Studies, 2018
Jinko Graham, Brad McNeneys, Robert Platt
Once the network that represents the support has been created, the next step is to superpose sampling weights that allow sampling of paths according to the target distribution. Sampling a path can be achieved by randomly selecting an arc to follow at each node visited during a pass through the network. [33] develop a recursive algorithm to calculate sampling weights for each arc such that randomly following arcs according to their weights produces a realization from . Although the resulting algorithm samples without rejection, the construction of the network can exhaust computer memory. The memory limitations of the Monte Carlo approach prompted development of Markov chain Monte Carlo approaches [17,44]. These are discussed in the next section.
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
OCT takes advantage of temporal and spatial coherence of the laser beam, and is based on a phenomenon called interference. In Section 3.3 we discussed one of the effects characteristic of wave motion – diffraction, one of the forms of deviation of light from a straight-path motion. All types of waves, including sound and water waves, undergo diffraction. Similarly, interference is another characteristic aspect of wave motion. Interference is an effect that occurs when two or more waves pass through the same point in space. When two electromagnetic waves intersect, the electric and magnetic disturbances in each of the waves combine, or superpose. The result of this superposition depends on whether the two waves have a consistent phase relationship with each other, in other words, whether they are coherent or not. If they are coherent, the superposition yields an interference pattern, a stable configuration of bright and dark stripes similar to those in a diffraction picture. The areas of increased brightness occur where the crests of the two waves overlap, so that the two waves reinforce each other, creating a bright fringe (Figure 3.36a). This is called constructive interference. Alternatively, when the crest of one wave overlaps with the trough of another the two waves cancel each other, producing a dark fringe (Figure 3.36b). This is called destructive interference. The coherence of light sources is a crucial condition for interference. When light sources are not coherent, the crests and troughs from different waves arrive at different times, blurring the interference pattern. This is what happens if we use two flashlights to illuminate a spot on a wall. Because the light waves from the two flashlights are not coherent, instead of an interference pattern, the only effect is an overall increase in brightness.
Copy-number variation of the NPHP1 gene in patients with juvenile Nephronophthisis
Published in Acta Clinica Belgica, 2021
Mayssa Abdelwahed, Ines Maaloul, Valerie Benoit, Pascale Hilbert, Mongia Hachicha, Hassen Kamoun, Leila Keskes-Ammar, Neila Belguith
In order to visualize the profile of MLPA fragment, we used the software Coffalyser.Net which makes it possible to superpose the profile of MLPA fragment of different individuals of the same plate. We obtained visual indices on the genotype of each one. Based on the result of the Coffalyser.Net software (MRC-Holland), the majority of individuals showed a satisfactory visual analysis. Peak intensities corresponded to each probe in the different samples and probes were separated from each other and had a symmetrical and regular shape, as shown in Figure 2. MLPA fragment profile of patient 1 and patient 2 showed the absence of all NPHP1 exon-specific probe peaks as compared to the reference fragment profile. These results indicate a homozygous deletion of the entire gene in both patients. Only the MLPA fragment profile of patient 1 and the control are shown in Figure 2. In addition, the probe ratios cross the lower arbitrary border of 0.7 (the red line) in both patients indicating a homozygote deletion of the entire gene as compared to the reference. Only the results of the ratio chart for patient 1 and the control are shown in Figure 3.
Molecular mechanism of an antagonistic antibody against glucose-dependent insulinotropic polypeptide receptor
Published in mAbs, 2020
Xiaoshan Min, Junming Yie, Jinghong Wang, Ben C. Chung, Ching-Shin Huang, Haoda Xu, Jie Yang, Liying Deng, Joanne Lin, Qing Chen, Christina M. Abbott, Caroline Gundel, Stephen A. Thibault, Tina Meng, Darren L. Bates, David J. Lloyd, Murielle M. Véniant, Zhulun Wang
To understand whether mAb1 binding affects endogenous ligand, we compared the complex structure of mouse GIPR ECD-Fab1 with the previously reported human GIPR ECD-GIP complex (PDB: 2QKH)33 (Figure S3). The mouse and human GIPR ECD share high sequence identity (78%), and the structures of the two proteins superpose well with a root-mean-square deviation of 0.89 Å for the Cα atoms. Mouse GIP also shares high sequence identity with human GIP, with only three mutations among 42 residues and none of the mutations involved in binding to GIPR. Due to the high-sequence conservation between human and mouse GIPR ECD ligand binding sites, we reason that mouse GIP interacts with mouse GIPR ECD in a similar manner as in the human homologue. The structure superposition reveals that there is no overlap between the endogenous ligand and Fab1 binding (Figure 2D). Fab1 sits on the opposite side of the GIP binding site in GIPR ECD, so the binding of Fab1 is unlikely to affect GIP binding. Thus, the co-crystal structure elucidates the molecular basis that mAb1 is a non-neutralizing high-affinity binder to GIPR, subsequently having no effect on GIP signaling.
Hygiene of venepuncture tourniquets in Denmark
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2018
Eva Rabing Brix Petersen, Mads Nybo
First, attention must be drawn to reusable devices. To avoid contamination, reuse should be discouraged, as patients acquiring nosocomial infections will result in increased costs likely to superpose the money spent on disposable equipment [15]. To calculate the exact amount saved requires a proper health-technology assessment, which certainly should be encouraged.