1,428 research outputs found
Quantitative wave function analysis for excited states of transition metal complexes
The character of an electronically excited state is one of the most important
descriptors employed to discuss the photophysics and photochemistry of
transition metal complexes. In transition metal complexes, the interaction
between the metal and the different ligands gives rise to a rich variety of
excited states, including metal-centered, intra-ligand, metal-to-ligand charge
transfer, ligand-to-metal charge transfer, and ligand-to-ligand charge transfer
states. Most often, these excited states are identified by considering the most
important wave function excitation coefficients and inspecting visually the
involved orbitals. This procedure is tedious, subjective, and imprecise.
Instead, automatic and quantitative techniques for excited-state
characterization are desirable. In this contribution we review the concept of
charge transfer numbers---as implemented in the TheoDORE package---and show its
wide applicability to characterize the excited states of transition metal
complexes. Charge transfer numbers are a formal way to analyze an excited state
in terms of electron transitions between groups of atoms based only on the
well-defined transition density matrix. Its advantages are many: it can be
fully automatized for many excited states, is objective and reproducible, and
provides quantitative data useful for the discussion of trends or patterns. We
also introduce a formalism for spin-orbit-mixed states and a method for
statistical analysis of charge transfer numbers. The potential of this
technique is demonstrated for a number of prototypical transition metal
complexes containing Ir, Ru, and Re. Topics discussed include orbital
delocalization between metal and carbonyl ligands, nonradiative decay through
metal-centered states, effect of spin-orbit couplings on state character, and
comparison among results obtained from different electronic structure methods.Comment: 47 pages, 19 figures, including supporting information (7 pages, 1
figure
Cooccurrence de violence conjugale et de maltraitance envers les enfants : points de vue des intervenants de la protection de la jeunesse
Cet article rend compte des résultats d’une étude exploratoire portant sur les pratiques d’intervention dans le domaine de la protection de la jeunesse concernant les situations où il y a violence conjugale et maltraitance envers les enfants. Plus précisément, l’étude permet de documenter les éléments pris en considération dans le dépistage et l’évaluation des situations de cooccurrence ainsi que les défis auxquels les intervenants sont confrontés dans ce type de cas. L’analyse qualitative du contenu de 43 entrevues montre que les intervenants reconnaissent l’existence des liens de cooccurrence entre les deux problématiques et l’importance d’en tenir compte dans l’intervention. La prise en compte de ces liens dans les pratiques d’intervention mises en oeuvre soulève toutefois des enjeux et des dilemmes importants concernant le dépistage et l’évaluation des situations ainsi que pour la création d’un lien de confiance et de collaboration avec les membres de la famille.This article shows the results of an exploratory study about intervention practices in youth protection in situations where conjugal violence and child maltreatment co-occur. More specifically, the study documents the elements taken into consideration to detect and assess the situations of cooccurrence as well as the stakes the social workers are confronted with in those cases. The qualitative analysis of 43 interviews shows that the social workers recognize the existence of the links of cooccurrence between both problems and the importance to take it into account in their interventions. However, the consideration of these links in the implemented practices raises stakes and an important dilemma concerning the detection and the evaluation of those situations as well as for the establishment of collaboration and trust with family members.Este artÃculo da cuenta de los resultados de un estudio exploratorio sobre las prácticas de intervención en el ámbito de la protección a la infancia en situaciones en que existe a la vez violencia conyugal y maltrato de menores. De manera más precisa, el estudio permite documentar los elementos que se toman en cuenta en la detección y evaluación de situaciones de coocurrencia, asà como los desafÃos a que se enfrentan los trabajadores sociales en este tipo de casos. El análisis cualitativo del contenido de 43 entrevistas muestra que los trabajadores sociales reconocen la existencia de relaciones de coocurrencia entre ambas problemáticas y la importancia de tomarlas en cuenta durante la intervención. La consideración de dichas relaciones constituye, sin embargo, un desafÃo en la práctica, pues plantea dilemas importantes respecto de la detección y la evaluación de esas situaciones, asà como para el establecimiento de un clima de confianza y colaboración con los miembros de la familia concernida
Interstate Vibronic Coupling Constants Between Electronic Excited States for Complex Molecules
In the construction of diabatic vibronic Hamiltonians for quantum dynamics in
the excited-state manifold of molecules, the coupling constants are often
extracted solely from information on the excited-state energies. Here, a new
protocol is applied to get access to the interstate vibronic coupling constants
at the time-dependent density functional theory level through the overlap
integrals between excited-state adiabatic auxiliary wavefunctions. We discuss
the advantages of such method and its potential for future applications to
address complex systems, in particular those where multiple electronic states
are energetically closely lying and interact. As examples, we apply the
protocol to the study of prototype rhenium carbonyl complexes
[Re(CO)(N,N)(L)] for which non-adiabatic quantum dynamics within the
linear vibronic coupling model and including spin-orbit coupling have been
reported recently.Comment: 36 pages, 7 figures, 4 table
Establishing thriving university-level space education
Recent analyses of the UK National Space Strategy [1], Space Sector Skills Survey [2] and The 2020 Space Census [3], have investigated and highlighted many of the established strengths and weaknesses of the current UK Space Sector and the role of training and educational programs supporting it. Furthermore, there is additional research into what self-reported roadblocks early career students and workers (and employers) consider important in this journey [4]. Academia, employers, schools, colleges, and museums all have considerable roles to play in shaping the future science capital of our populace and establishing people on the tech workforce pipeline. Rising to meet this challenge, The University of Nottingham wants to develop the UK's space workforce and is proud to have begun its first dedicated aerospace undergraduate course in 2016. In addition to the core lecture modules, added project experience is available in the form of group and individual supervised projects. These practical activities are a rare opportunity to learn unique space skills and work hands-on with spacecraft technology, something in short supply in the UK at the undergraduate level [2]. The practical, hands-on components are an important part of the space education programme and involve different platforms and projects going from simple electronics workshops to CanSats, FlatSats and experimental Rockets. These activities culminate in the CubeSat Program: a student-led group of projects to develop, build and fly CubeSat missions with a variety of payloads. The students have the possibility to present their own mission idea or join existing ones of interest to the research community. To support these high-fidelity opportunities for students and early career workers, a permanent on-site COTS Ground Station will serve as a control center for all these student-built satellite missions. To help with the establishment of this facility, The University of Nottingham has been cooperating with the local amateur radio community to train and license the student team. This paper deals with the description of the different projects and presents the University’s point of view about the strengths and weaknesses of our Space educational programm
Biochemical disorders induced by cytotoxic marine natural products in breast cancer cells as revealed by proton NMR spectroscopy-based metabolomics
International audienceMarine plants and animals are sources of a huge number of pharmacologically active compounds, some of which exhibit antineoplastic activity of clinical relevance. However the mechanism of action of marine natural products (MNPs) is poorly understood. In this study, proton NMR spectroscopy-based metabolomics was applied to unravel biochemical disorders induced in human MCF7 breast cancer cells by 3 lead candidate anticancer MNPs: ascididemin (Asc), lamellarin-D (Lam-D), and kahalalide F (KF). Asc, Lam-D, and KF provoked a severe decrease in DNA content in MCF7 cells after 24h treatment. Asc and Lam-D provoked apoptosis, whereas KF induced non-apoptotic cell death. Metabolite profiling revealed major biochemical disorders following treatment. The response of MCF7 tumor cells to Asc involved the accumulation of citrate (×17 the control level, <0.001), testifying enzyme blockade in citrate metabolism, and the accumulation of gluconate (×9.8, <0.005), a metabolite never reported at such concentration in tumor cells, probably testifying glycolysis shutdown. The response to Lam-D involved the accumulation of aspartate (×7.2, <0.05), glutamate (×14.7, <0.05), and lactate (×2.3, <0.05), probably in relation with the targeting of the malate-aspartate shuttle, as discussed. The response to KF involved increased lipid accumulation (polyunsaturated fatty acids ×9.8, <0.05), and phospholipid and acetate derivative alterations. Altogether, this study demonstrates the potential of proton NMR spectroscopy-based metabolomics to help uncover metabolic targets and elucidate the mechanism of cytotoxicity of candidate antineoplastic MNPs
Functional correlates of optic flow motion processing in Parkinson’s disease
The visual input created by the relative motion between an individual and the environment, also called optic flow, influences the sense of self-motion, postural orientation, veering of gait, and visuospatial cognition. An optic flow network comprising visual motion areas V6, V3A, and MT+, as well as visuo-vestibular areas including posterior insula vestibular cortex (PIVC) and cingulate sulcus visual area (CSv), has been described as uniquely selective for parsing egomotion depth cues in humans. Individuals with Parkinson’s disease (PD) have known behavioral deficits in optic flow perception and visuospatial cognition compared to age- and education-matched control adults (MC). The present study used functional magnetic resonance imaging (fMRI) to investigate neural correlates related to impaired optic flow perception in PD. We conducted fMRI on 40 non-demented participants (23 PD and 17 MC) during passive viewing of simulated optic flow motion and random motion. We hypothesized that compared to the MC group, PD participants would show abnormal neural activity in regions comprising this optic flow network. MC participants showed robust activation across all regions in the optic flow network, consistent with studies in young adults, suggesting intact optic flow perception at the neural level in healthy aging. PD participants showed diminished activity compared to MC particularly within visual motion area MT+ and the visuo-vestibular region CSv. Further, activation in visuo-vestibular region CSv was associated with disease severity. These findings suggest that behavioral reports of impaired optic flow perception and visuospatial performance may be a result of impaired neural processing within visual motion and visuo-vestibular regions in PD.Published versio
Prefigurative performance in the age of political deception
The most notable forms of activism in recent years, prefigurative interventions and occupations, are comparable to theatrical performance by embodying, situating and interacting hypothetical scenarios. The mutual points of political performance lies in open-ended, horizontal performance practices such as site-sensitive interventions, tactical media, applied theatre and cognate modes of interactive performance. Whilst several examples of such overlapping performance phenomena are given and justified in the article, the political disciplines also face mutual challenges from hegemonic politics and thus share a need to adapt their performative effects into sustainable social movements
Case Report of a Remote Ischemic Preconditioning Intervention during Aerobic Exercise in a 44-year-old Amateur Triathlete Male with a History of Acute Myocardial Infarction
International Journal of Exercise Science 13(3): 924-937, 2020. Over the years, exercise has become increasingly important in patients with acute myocardial infarction (AMI). However, AMI patients need to be closely monitored since they maintain cardiovascular disease risks, such as ventricular repolarization abnormalities in electrocardiograms during exercise and rest. A recent study showed the need to focus on the different potential mechanisms and the applicability of remote ischemic preconditioning (RIPC) for cardiac patients engaged in exercise rehabilitation. This is the first case report that explores the effectiveness of an RIPC intervention in a 44-year-old amateur triathlete male with a history of AMI during a moderate (75% of gas exchange threshold) and high (115% of gas exchange threshold) intensity steady-state cycling aerobic exercise. Prior to aerobic exercise, the participant was allocated to either RIPC intervention or CTL (control) with four cycles of five minutes of ischemia followed by five minutes of reperfusion. ECG was continuously recorded during the protocol. These findings showed that RIPC improved participant’s oxygen uptake response and shortened his ventricular repolarization during steady-state aerobic exercises. By measuring the physiological and electrophysical parameters, this case report adds new evidence for the benefits of RIPC. This study also demonstrates the safety of the intervention for cardiac patients in addition to showing that the intervention is not dangerous or harmful. This provides a new approach to cardiac rehabilitation programs. Future studies with cardiac patients are needed to provide a safe, standardized exercise intervention in cardiac rehabilitation
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