The new extended Monte Carlo (MC) simulation method for photon transport in S(T)EM back scattered electron (BSE) scintillation detection systems of various shapes is presented in this paper. The method makes use of the random generation of photon emission from a scintillator luminescent centre and describes the trajectory of photons and the efficiency of their transport toward the photocathode of the photomultiplier tube. The paper explains a new algorithm for determining the position of interaction of the photon with the surface of the single crystal scintillator or of the light guide with nearly arbitrary shapes. Some examples of the utilization of the simulation method are also included, and conclusions for very simple edge-guided signal (EGS) scintillation detection systems made. The computer optimized design of the BSE scintillation detector for the S 4000 Hitachi SEM was chosen to demonstrate the capability of this MC simulation method.
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http://dx.doi.org/10.1002/sca.20072 | DOI Listing |
Protein Sci
February 2025
Amherst College, Amherst, Massachusetts, USA.
Hydrogen exchange mass spectrometry (HXMS) is a powerful tool to understand protein folding pathways and energetics. However, HXMS experiments to date have used exchange conditions termed EX1 or EX2 which limit the information that can be gained compared to the more general EXX exchange regime. If EXX behavior could be understood and analyzed, a single HXMS timecourse on an intact protein could fully map its folding landscape without requiring denaturation.
View Article and Find Full Text PDFStat Med
February 2025
Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas, USA.
Multi-gene panel testing allows efficient detection of pathogenic variants in cancer susceptibility genes including moderate-risk genes such as ATM and PALB2. A growing number of studies examine the risk of breast cancer (BC) conferred by pathogenic variants of these genes. A meta-analysis combining the reported risk estimates can provide an overall estimate of age-specific risk of developing BC, that is, penetrance for a gene.
View Article and Find Full Text PDFStat Med
February 2025
Biostatistics, Innovatio Statistics Inc., Bridgewater, New Jersey, USA.
Sample size re-estimation (SSR) is perhaps the most used adaptive procedure in both frequentist and Bayesian adaptive designs for clinical trials. The primary focus of all current frequentist and Bayesian SSR procedures is type I error control. We propose a hybrid frequentist-Bayesian SSR approach that focuses on optimizing operating characteristics (OC), which uses simulations to investigate the associated OC and adjusts accordingly.
View Article and Find Full Text PDFStem Cell Res Ther
January 2025
Organoid Innovation Center, Suzhou Institute of Nanotech and Nano-bionics, Chinese Academy of Sciences, 398 Ruoshui Rd, Suzhou, Jiangsu, 215123, China.
The lack of in vivo accurate human liver models hinders the investigation of liver-related diseases, injuries, and drug-related toxicity, posing challenges for both basic research and clinical applications. Traditional cellular and animal models, while widely used, have significant limitations in replicating the liver's complex responses to various stressors. Liver organoids derived from human pluripotent stem cells, adult stem cells primary cells, or tissues can mimic diverse liver cell types, major physiological functions, and architectural features.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
Background: The spatial resolution of new, photon counting detector (PCD) CT scanners is limited by the size of the focal spot. Smaller, brighter focal spots would melt the tungsten focal track of a conventional X-ray source.
Purpose: To propose focal spot multiplexing (FSM), an architecture to improve the power of small focal spots and thereby enable higher resolution clinical PCD CT.
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