Experiment and theory are combined to study the interaction of low energy electrons with microhydrated uracil and its halogenated analogues 5-fluorouracil and 5-bromouracil. We report electron ionization (EI) and electron attachment (EA) mass spectra for the uracils with different degrees of hydration. Both EI and EA lead to evaporation of water molecules. The number of evaporated molecules serves as a measure of the energy transferred to the solvent. Upon EI, the amount of energy transferred to neighboring water molecules is similar for all three studied species. On the other hand, the energy transferred upon EA rises significantly from uracil to 5-fluorouracil and 5-bromouracil. 5-Bromouracil is the only studied molecule that undergoes dissociative electron attachment after hydration at the studied energy of 1.2 eV. Theoretical modeling of the energetics for the electron attachment process allows for setting the energy transferred to the solvent on the absolute scale. We discuss the importance of this energy for the radiosensitization.
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http://dx.doi.org/10.1021/acs.jpcb.7b07390 | DOI Listing |
Phys Imaging Radiat Oncol
October 2024
Aarhus University Hospital, Danish Centre for Particle Therapy, Aarhus N, Denmark.
Background And Purpose: Radiotherapy for paediatric posterior fossa tumours may cause complications in the brainstem and upper spinal cord due to high doses. With proton therapy (PT) this risk may increase due to higher relative biological effectiveness (RBE) from elevated linear energy transfer (LET). This study assesses variations in LET in the brainstem and spinal cord in proton treatment plans from European centres.
View Article and Find Full Text PDFBio Protoc
January 2025
Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Riken, 2-1 Hirosawa, Wako Saitama, Japan.
Cytosolic peptide:-glycanase (PNGase/NGLY1 in mammals), an amidase classified under EC:3.5.1.
View Article and Find Full Text PDFFood Sci Nutr
January 2025
Faculty of Chemical and Food Engineering, Bahir Dar Institute of Technology Bahir Dar University Bahir Dar Ethiopia.
This study investigates the optimization of four gluten free flours namely sorghum, rice, teff flours, and 3% flaxseed flour blends to enhance the quality , which was traditionally baked with only pure teff. Utilizing a D-optimal mixture design, ratios were varied (sorghum 43%-50%, rice 20%-27%, teff 23%-30%). Methods followed AOAC and AACC standards, analyzed using Minitab 19.
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December 2024
College of Materials Science and Engineering, Fuzhou University New Campus 350108 China
Atomically precise metal nanoclusters (NCs) have recently been recognized as an emerging sector of metal nanomaterials but suffer from light-induced poor stability, giving rise to the detrimental self-transformation into metal nanocrystals (NYs), losing the photosensitization effect and ultimately retarding their widespread applications in photoredox catalysis. Are metal NCs definitely superior to metal NYs in heterogeneous photocatalysis in terms of structural merits? To unlock this mystery, herein, we conceptually demonstrate how to rationally manipulate the instability of metal NCs to construct high-efficiency artificial photosystems and examine how the metal NYs self-transformed from metal NCs influence charge transfer in photoredox selective organic transformation. To our surprise, the results indicate that the Schottky-type electron-trapping ability of Au NYs surpasses the photosensitization effect of glutathione (GSH)-protected Au clusters [Au(GSH) NCs] in mediating charge separation and enhancing photoactivities towards selective photoreduction of aromatic nitro compounds to amino derivatives and photocatalytic oxidation of aromatic alcohols to aldehydes under visible light irradiation.
View Article and Find Full Text PDFChem Sci
December 2024
Institut de Quimica Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona M. Aurèlia Capmany, 69 17003 Girona Catalonia Spain
Photodynamic therapy is an important tool in modern medicine due to its effectiveness, safety, and the ability to provide targeted treatment for a range of diseases. Photodynamic therapy utilizes photosensitizers to generate reactive oxygen species (ROS). Fullerenes can be used as photosensitizers to produce ROS in high quantum yields.
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