Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with E > = 6×1019 eV by analyzing cosmic rays with energies above E > = 5×1018 eV arriving within an angular separation of approximately 15°. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources

Building a Functionalizable, Potent Chemiluminescent Agent: A Rational Design Study on 6,8-Substituted Luminol Derivatives

Luminol is a prominent chemiluminescent (CL) agent, finding applications across numerous fields, including forensics, immunoassays, and imaging. Different substitution patterns on the aromatic ring can enhance or decrease its CL efficiency. We herein report a systematic study on the synthesis and photophysics of all possible 6,8-disubstituted luminol derivatives bearing H, Ph, and/or Me substituents. Their CL responses are monitored at three pH values (8, 10, and 12), thus revealing the architecture with the optimum CL efficiency. The most efficient pattern is used for the synthesis of a strongly CL luminol derivative, bearing a functional group for further, straightforward derivatization. This adduct exhibits an unprecedented increase in chemiluminescence efficiency at pH = 12, pH = 10, and especially at pH = 8 (closer to the biologically relevant conditions) compared to luminol. Complementary work on the fluorescence of the emissive species as well as quantum chemistry computations are employed for the rationalization of the observed results. © 2021 American Chemical Society

Building a Functionalizable, Potent Chemiluminescent Agent: A Rational Design Study on 6,8-Substituted Luminol Derivatives

Luminol is a prominent chemiluminescent (CL) agent, finding applications across numerous fields, including forensics, immunoassays, and imaging. Different substitution patterns on the aromatic ring can enhance or decrease its CL efficiency. We herein report a systematic study on the synthesis and photophysics of all possible 6,8-disubstituted luminol derivatives bearing H, Ph, and/or Me substituents. Their CL responses are monitored at three pH values (8, 10, and 12), thus revealing the architecture with the optimum CL efficiency. The most efficient pattern is used for the synthesis of a strongly CL luminol derivative, bearing a functional group for further, straightforward derivatization. This adduct exhibits an unprecedented increase in chemiluminescence efficiency at pH = 12, pH = 10, and especially at pH = 8 (closer to the biologically relevant conditions) compared to luminol. Complementary work on the fluorescence of the emissive species as well as quantum chemistry computations are employed for the rationalization of the observed results.The authors would like to thank Ekaterini Bouga and Christina-Ioanna Vrettou for assisting with certain synthesis steps. This project was financially supported by the European Union’s Horizon 2020 framework program for research and innovation under Grant Agreement No. 712921. T.M. and A.P. would like to thank the State Scholarships Foundation (IKY) for financial support via Ph.D. fellowships through the “Strengthening of Human Resources through Doctoral Research” program of the Operational Program “Human Resource Development, Education and Lifelong Learning” 2014–2020, co-financed by the European Union (European Social Fund ESF) and Greek national funds. The authors would also like to thank Prof. N. Thomaidis and Dr. Maria-Christina for the HRMS analyses. M.A.M. and G.M.R.-M. thank the Generalitat Valenciana (Prometeo Program/2017/075) for financial support. A.G. and D.R.-S. acknowledge Spanish “Ministerio de Ciencia e Innovación (MICINN)” (Project Ref CTQ2017-87054-C2-2-P). A.G. is also thankful to the MICINN for a “Juan de la Cierva” grant (Ref IJC2018-035123-I). D.R.-S. is also thankful to the MICINN for a “Ramón y Cajal” grant (Ref RYC-2015-19234) and to the BBVA Foundation for a 2019 Leonardo Grant for Researchers and Cultural Creators