Energy transfer in luminescent lanthanoid chelates

Luminescent lanthanoid complexes are widely utilized, especially in the medical diagnostics. The complexes have been much studied and ligands with high quantum efficiency have been developed for different lanthanoid ions and for different applications. However, the present ligands are not applicable for all applications, for example for biological imaging, which would require excitation by visible light, water solubility and stability in the aqueous environments. The development of ligands for these applications would require a better knowledge of the fundamental processes in lanthanoid luminescence. In spite of numerous studies, additional information is still needed, at least regarding the energy transfer in chelates. The role of different energy states in the energy transfer processes, especially, would require more studies. The aim of this thesis is to provide new information about the energy transfer phenomenon. The results show that the roles of the ligand energy states in the energy transfer processes are depended only on their relative positions with respect to the receiving Ln(III) states and the energy transfer rates between the states but not on the nature of the energy states. The determination of the singlet and intraligand charge transfer state energies with the help of absorption and emission spectra is an important result, which helps to show that the energy back-transfer takes place from Ln(III) to the emittive intraligand CT state. In addition, the method for the determination of the stability constant utilizing the luminescence intensity was developed. According to this work, it seems that the absolute values of the ligand energy states should not be taken into consideration in the ligand development but rather the information provided by the (deconvoluted) fluorescence and phosphorescence emission bands of the ligands. In addition, new efficient ligands and their complexes with Eu(III) and Tb(III) have been studied. These can be exited by visible light and used in aqueous media

Social Tie Strength and Online Victimization : An Analysis of Young People Aged 15-30 Years in Four Nations

Online interaction through the use of social networking sites (SNS) continues to be a significant component of the socialization of young people today, yet little research exists toward linking various relational forms to prevalent and much-studied online risks cross-nationally. This article provides a link between relational dynamics and online risks identified in previous research toward a new perspective on how social tie strength is related to experiences of hate victimization and harassment online. The analysis is based on survey data of Finnish (n = 555), American (n = 1033), German (n = 978), and British (n = 999) young people aged 15-30 years. Variables, including age, gender, main activity, SNS use, quantity, and extent of online and offline social networks including social tie strength and online community identification, were analyzed toward finding their associations with online hate victimization and harassment. Results showed that experiences of hate victimization and harassment were similar cross-nationally and that those who were personally harassed online also reported high SNS activity. Furthermore, no association was found between social network size and negative experiences. Notable cross-national differences were also detected in the results. Findings emphasize the importance of understanding variables fostering online risks for young people while providing a new perspective on what aspects of social life may help negate negative effects online.Peer reviewe

Perusteita seuraavan sukupolven metsävarajärjestelmälle – Forest Big Data -hanke

Tieteen tori: Yksityiskohtainen metsävaratiet

Energy transfer in ternary TbEDTA chelates with a series of dipicolinic acid derivatives

The energy transfer in lanthanoid chelates was studied using the ternary TbEDTA (EDTA ¼ethyl-enediaminetetraacetic acid) chelates with several dipicolinic acid derivatives (pyridine-2,6-dicarboxylic acid (L1, dpa), 4-(9H-fluoren-3-yl)pyridine-2,6-dicarboxylic acid (L2), 4-(dibenzo [b,d]furan-2-yl)pyridine-2,6- dicarboxylic acid (L3), 4-(dibenzo [b,d]thiophen-2-yl)pyridine-2,6-dicarboxylic acid (L4) and 4-(9H-carbazol- 3-yl)pyridine-2,6-dicarboxylic acid (L5)) and spectroscopic methods (absorption and luminescence spectroscopy and the effect of argon treatment and temperature on luminescence lifetime(s)). The results revealed that the ILCT (intra-ligand charge transfer) state is inefficient in exciting the Tb(III) ion and the emissive states of the ligands, as well as the triplet states, act as quenching states by receiving energy back transfer from the Tb(III) ion. The stability constants for these ternary complexes were also determined.</p

Perceived Societal Fear and Cyberhate after the November 2015 Paris Terrorist Attacks

Fear is one of the negative outcomes of terrorist attacks. Currently, there is a need to understand how societal fear and fear of terrorism might be shaped and induced by social-media discussions. This study analyzed how exposure to cyberhate was associated with perceived societal fear after the November 2015 Paris terrorist attacks. Demographically balanced data sets were collected from France, Spain, Finland, Norway, and the United States four weeks after the attacks. Cyberhate exposure was associated with higher perceived societal fear in all countries studied even when adjusting for confounding factors. This was particularly evident in the case of cyberhate related to terrorism. Hateful online communication after disruptive events may contribute to a social climate of fear and escalate societal uncertainty. There are, however, indications that social trust may bolster against perceived societal fear, hence enhancing resilience.</p

Perceived societal fear and cyberhate after the November 2015 Paris Terrorist Attacks

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Harnessing sensing systems towards urban sustainability transformation

Peer reviewe

VEGF-B Promotes Endocardium-Derived Coronary Vessel Development and Cardiac Regeneration

cited By 1Background: Recent discoveries have indicated that, in the developing heart, sinus venosus and endocardium provide major sources of endothelium for coronary vessel growth that supports the expanding myocardium. Here we set out to study the origin of the coronary vessels that develop in response to vascular endothelial growth factor B (VEGF-B) in the heart and the effect of VEGF-B on recovery from myocardial infarction. Methods: We used mice and rats expressing a VEGF-B transgene, VEGF-B-gene-deleted mice and rats, apelin-CreERT, and natriuretic peptide receptor 3-CreERT recombinase-mediated genetic cell lineage tracing and viral vector-mediated VEGF-B gene transfer in adult mice. Left anterior descending coronary vessel ligation was performed, and 5-ethynyl-2'-deoxyuridine-mediated proliferating cell cycle labeling; flow cytometry; histological, immunohistochemical, and biochemical methods; single-cell RNA sequencing and subsequent bioinformatic analysis; microcomputed tomography; and fluorescent- and tracer-mediated vascular perfusion imaging analyses were used to study the development and function of the VEGF-B-induced vessels in the heart. Results: We show that cardiomyocyte overexpression of VEGF-B in mice and rats during development promotes the growth of novel vessels that originate directly from the cardiac ventricles and maintain connection with the coronary vessels in subendocardial myocardium. In adult mice, endothelial proliferation induced by VEGF-B gene transfer was located predominantly in the subendocardial coronary vessels. Furthermore, VEGF-B gene transduction before or concomitantly with ligation of the left anterior descending coronary artery promoted endocardium-derived vessel development into the myocardium and improved cardiac tissue remodeling and cardiac function. Conclusions: The myocardial VEGF-B transgene promotes the formation of endocardium-derived coronary vessels during development, endothelial proliferation in subendocardial myocardium in adult mice, and structural and functional rescue of cardiac tissue after myocardial infarction. VEGF-B could provide a new therapeutic strategy for cardiac neovascularization after coronary occlusion to rescue the most vulnerable myocardial tissue.Peer reviewe