Search results for "potential"

Adenine and 2-aminopurine: Paradigms of modern theoretical photochemistry

2006

Distinct photophysical behavior of nucleobase adenine and its constitutional isomer, 2-aminopurine, has been studied by using quantum chemical methods, in particular an accurate ab initio multiconfigurational second-order perturbation theory. After light irradiation, the efficient, ultrafast energy dissipation observed for nonfluorescent 9H-adenine is explained here by the nonradiative internal conversion process taking place along a barrierless reaction path from the initially populated 1 (ππ* L a ) excited state toward a low-lying conical intersection (CI) connected with the ground state. In contrast, the strong fluorescence recorded for 2-aminopurine at 4.0 eV with large decay lifetime …

2015

Primary neuronal cultures share many typical features with the in vivo situation, including similarities in distinct electrical activity patterns and synaptic network interactions. Here, we use multi-electrode array (MEA) recordings from spontaneously active cultures of wildtype and GAD67-GFP transgenic mice to evaluate which spike parameters differ between GABAergic interneurons and principal, putatively glutamatergic neurons. To analyze this question we combine MEA recordings with optical imaging in sparse cortical cultures to assign individual spikes to visually-identified single neurons. In our culture system, excitatory and inhibitory neurons are present at a similar ratio as described…

A theoretical study of the intramolecular charge transfer in 4-(dimethylamino)benzethyne

2014

We have investigated the non-adiabatic relaxation processes occurring in the singlet manifold of 4-(dimethylamino)benzethyne (DMABE){,} a molecule isoelectronic with 4-(dimethylamino)benzonitrile (DMABN) but lacking its characteristic dual fluorescence{,} using multireference perturbation theory methods. The results obtained point out to the existence of a two-fold decay mechanism in which the population of the initially accessed La state bifurcates towards a locally excited (LE) and a [small pi][sigma]* state. Further relaxation to an emitting intramolecular charge transfer (ICT) state is impeded due to the presence of pronounced energy barriers along their associated potential energy surf…

Chapter 21 Immunohistochemical evidence for a co-transmitter role of opioid peptides in primary sensory neurons

1988

Publisher Summary The purpose of this chapter is to answer several open questions regarding opioid peptides by using a highly sensitive light microscopic (LM) immunohistochemical approach. The chapter mentions the immunohistochemical evidence for a co-transmitter role of opioid peptides in primary sensory neurons. It introduces the concept that there is a functionally important tandem constellation of transmitters in a specific nociceptive population of primary sensory afferents consisting of (1) an inhibitory transmitter family, the opioid peptides, and (2) an excitatory transmitter family, the tachykinins. Small-diameter primary sensory neurons not only transmit nociceptive messages to ce…

150 years of rowing faster: what are the sources of more and more speed?

2015

Rowing has a 150 yr+ competitive history. Examining results from historic races like Oxford-Cambridge (established 1829) and the world championships (established 1893) reveals a linear increase in boat speed by 2-3% per decade. Boat velocity increases if propulsive power is increased and/or power losses are reduced. Over time, the propulsive power capacity of elite rowers has increased. Part of this increase is a result of recruiting athletes from a population that has become taller (1-3 cm per decade) and heavier. Modern world class rowers are typically 190-200 cm tall and weigh 90-100 kg. However, physical capacity does not scale directly with body dimensions but conforms instead to biolo…

On the mechanical stability and out-of-plane dynamics of a travelling panel submerged in axially flowing ideal fluid : a study into paper production …

2011

Electrocatalytic rate constants from DFT simulations and theoretical models: Learning from each other

2022

Electrochemical interfaces present an extraordinarily complex reaction environment and several, often counter-acting, interactions contribute to rate constants of electrocatalytic reactions. We compile a short review on how electrode potential, solvent, electrolyte, and pH effects on electrocatalytic rates can be understood and modelled using computational and theoretical methods. We address the connections between computational models based on DFT and (semi)analytical model Hamiltonians to extract physical or chemical insights, identify some omissions in present DFT simulation approaches and analytic models, and discuss what and how simulations and models could learn from each other. peerR…

Taking Familiar Others’ Perspectives to Regulate Our Own Emotion: An Event-Related Potential Study

2019

Current research on emotion regulation has mainly focused on Gross’s cognitive strategies for regulating negative emotion; however, little attention has been paid to whether social cognitive processes can be used to regulate both positive and negative emotions. We considered perspective-taking as an aspect of social cognition, and investigated whether it would affect one’s own emotional response. The present study used a block paradigm and event-related potential (ERP) technology to explore this question. A 3 (perspective: self vs. pessimistic familiar other vs. optimistic familiar other) × 3 (valence: positive vs. neutral vs. negative) within-group design was employed. Thirty-six college s…

Proanthocyanidins and Where to Find Them: A Meta-Analytic Approach to Investigate Their Chemistry, Biosynthesis, Distribution, and Effect on Human He…

2021

Proanthocyanidins (PACs) are a class of polyphenolic compounds that are attracting considerable interest in the nutraceutical field due to their potential health benefits. However, knowledge about the chemistry, biosynthesis, and distribution of PACs is limited. This review summarizes the main chemical characteristics and biosynthetic pathways and the main analytical methods aimed at their identification and quantification in raw plant matrices. Furthermore, meta-analytic approaches were used to identify the main plant sources in which PACs were contained and to investigate their potential effect on human health. In particular, a cluster analysis identified PACs in 35 different plant famili…

Coarse-Graining Intermolecular Interactions in Dispersions of Highly Charged Colloids

2012

International audience; Effective pair potentials between charged colloids, obtained from Monte Carlo simulations of two single colloids in a closed cell at the primitive model level, are shown to reproduce accurately the structure of aqueous salt-free colloidal dispersions, as determined from full primitive model simulations by Linse et al. (Linse, P.; Lobaskin, V. Electrostatic Attraction and Phase Separation in Solutions of Like-Charged Colloidal Particles. Phys. Rev. Lett.1999, 83, 4208). Excellent agreement is obtained even when ion-ion correlations are important and is in principle not limited to spherical particles, providing a potential route to coarse-grained colloidal interactions…