Understanding the details of DNA damage caused by high-energy particles or photons is complicated by the multitude of reactive species, arising from the ionization and dissociation of HO, DNA, and protein. In this work, oligonucleotides (ODNs) are irradiated with a beam of low-energy electrons of 1.3 to 2.3 eV, which can only induce damage via the decay of shape resonances into various dissociative electron attachment channels. Using LC-MS/MS analysis, the major products are the release of nonmodified nucleobases (NB; Cyt ≫ Thy ∼ Ade > Gua). Additional damage includes 5,6-dihydropyrimidines (dHT > dHU) and eight nucleosides with modified sugar moieties consisting of 2',3'- and 2',5'-dideoxynucleosides (ddG > ddA ∼ ddC > ddT). The distribution of products is remarkably different in a 16-mer ODN compared to that observed previously with thymidylyl-(3'-5')-thymidine. This difference is explained by electron delocalization occurring within a sufficiently long strand, the DEA theory of O'Malley, and recent time-dependent density functional theory calculations.
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http://dx.doi.org/10.1021/acs.jpcb.2c01851 | DOI Listing |
Background: Hypothyroidism is a common sequela after radiotherapy for nasopharyngeal carcinoma (NPC). Magnetic resonance imaging (MRI) has gained prominence in thyroid imaging, leveraging its non-ionizing radiation, high spatial resolution, multiparameter and multidirectional imaging. Few previous studies have investigated the evaluation of radiation-induced thyroid injury by MRI.
View Article and Find Full Text PDFAm J Sports Med
January 2025
Department of Orthopedic Surgery, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
Background: To achieve successful anatomic rotator cuff repair with minimal tension, both the tear pattern and tear size should be considered. However, little information is available concerning the frequency of tear patterns and their effects on tendon healing.
Purpose: To evaluate the distribution of tear patterns in full-thickness rotator cuff tears and whether these patterns affect tendon healing after arthroscopic repair.
Sci Rep
January 2025
Inner Mongolia Research Institute, China University of Mining and Technology (Beijing), Ordos, 017000, China.
Based on a prototype of the Beijing subway tunnel, this research conducts large-scale model experiments to systematically investigate the vibration response patterns of tunnels with different damage levels under the influence of measured train loads. Initially, the polynomial fitting modal identification method (Levy) and the model test preparation process are introduced. Then, using time-domain peak acceleration, frequency response function, frequency-domain modal frequency, and modal shape indicators, a detailed analysis of the tunnel's dynamic response is conducted.
View Article and Find Full Text PDFMagn Reson Imaging
January 2025
Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37232, USA. Electronic address:
Background: Inductively coupled wireless coils are increasingly used in MRI due to their cost-effectiveness and simplicity, eliminating the need for expensive components like preamplifiers, baluns, coil plugs, and coil ID circuits. Existing tools for predicting component values and electromagnetic (EM) fields are primarily designed for cylindrical volume coils, making them inadequate for irregular volume-type wireless coils.
Purpose: The aim of this study is to introduce and validate a novel magnetic (H-) field probe-based co-simulation method to accurately predict capacitance values and EM fields for irregular volume-type wireless coils, thereby addressing the limitations of current prediction tools.
Ultrasonics
January 2025
State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, China.
Steel precision matching parts are widely used in aerospace and automobiles. In order to ensure the stability of the system, the matching parts' mating surfaces, such as inner holes and outer shafts, are required to achieve nano-surface roughness and submicron-shape accuracy. Diamond-cutting technology is generally used for ultra-precision machining processes.
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