Distortion caused by local static field variations in magnetic resonance imaging can be corrected by using a method developed by Chang and Fitzpatrick (CF) that requires two acquisitions identical except for the polarity of the read gradient. This approach has previously been applied to spin-echo imaging. In this report, its role in correcting geometric distortion in gradient-echo imaging is investigated using a dynamic programming algorithm. This approach appears to successfully handle many of the edge artifacts otherwise inherent in the CF method. Once the correction has been made, it is then possible to extract the local magnetic field itself. Magn Reson Med 42:585-590, 1999.
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Nat Commun
January 2025
Department of Chemistry, Michigan State University, East Lansing, Michigan, USA.
The formation of following the double ionization of small organic compounds via a roaming mechanism, which involves the generation of H and subsequent proton abstraction, has recently garnered significant attention. Nonetheless, a cohesive model explaining trends in the yield of characterizing these unimolecular reactions is yet to be established. We report yield and femtosecond time-resolved measurements following the strong-field double ionization of CHX molecules, where X = OD, Cl, NCS, CN, SCN, and I.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan, Hubei 430074, China.
Front Oral Health
December 2024
Department of Oral Medicine and Radiology, Panineeya Dental College, Hyderabad, India.
Background: Intraoral radiography remains the most widely employed dental radiographic technique for producing geometrically accurate images with minimal distortion and magnification. Despite its common use in the dental office, incorrect projection geometry can be challenging leading to image distortions. To mitigate these inaccuracies specific radiographic landmarks on the face are utilized during periapical radiography.
View Article and Find Full Text PDFJ Hum Evol
January 2025
Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China.
The hominin mandible SK 15 was discovered in April 1949 in Swartkrans Member 2, dated to ∼1.4 Ma. Albeit distorted on the right side, the left and right corpus of SK 15 are relatively low and thick, even compared to most Early to Middle Pleistocene Homo specimens.
View Article and Find Full Text PDFNat Commun
January 2025
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui, China.
Control of crack propagation is crucial to make tougher heterogeneous materials. As a crack interacts with material heterogeneities, its front distorts and adopts complex tortuous configurations. While the behavior of smooth cracks with straight fronts in homogeneous materials is well understood, the toughening by rough cracks with tortuous fronts in heterogeneous materials remains unsolved.
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