Is the S2→S0 internal conversion an important pathway for radiationless decay of the S2 state of azulene?

1984 ◽  
Vol 31-32 ◽  
pp. 589-591 ◽  
Author(s):  
A.L. Sobolewski ◽  
J. Prochorow
Keyword(s):  
Internal Conversion ◽  
Important Pathway ◽  
Radiationless Decay ◽  
S2 State

Biradical radiationless decay channel in adenine and its derivatives

2007 ◽  
Vol 85 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Marek Z Zgierski ◽  
Serguei Patchkovskii ◽  
Edward C Lim
Keyword(s):  
Unpaired Electron ◽  
Internal Conversion ◽  
Decay Channel ◽  
Atomic Orbital ◽  
Electronic Configuration ◽  
Membered Ring ◽  
Direct Decay ◽  
Radiationless Decay ◽  
P Type ◽  
Π State

Coupled-cluster calculations of increasing accuracy (approximate doubles: CC2; doubles: EOM-CCSD; connected triples: CR-EOM-CCSD(T)) for CIS-optimized potential energy profiles of adenine and its derivatives indicate that the ultrafast internal conversion of the optically excited π π* state occurs through a state switch to a biradical state, which intersects the ground state at a lower energy. The electronic nature of the biradical state is defined by an electronic configuration in which one unpaired electron occupies a π* orbital confined to the five-membered ring. The second unpaired electron is localized very strongly on a p-type C2 atomic orbital of the six-membered ring. The biradical state minimum has a strongly puckered six-membered ring and a C2–H bond, which is twisted nearly perpendicular to the average ring plane. Consistent with the biradical-mediated internal conversion, the π π* state lifetime is extremely short in adenine and 9-methyladenine, which have barrierless crossing to the biradical state. The lifetime is slightly longer in N,N-dimethyladenine, which has a small barrier for the state switch. In 2-aminopurine the biradical state is found above the π π* state, preventing the biradical state switch and dramatically increasing the lifetime. These results, combined with an earlier work on pyrimidine bases, strongly suggest the importance of a direct decay of the doorway π π* state via a biradical state switch in the photophysics of DNA, even though the nature of the biradical state is somewhat different in purines and pyrimidines.Key words: adenine, guanine, DNA damage, radiationless decay, biradical, ab initio, coupled clusted.

The geometry relaxation and photodeactivation from the S2 state of dibenzofuran studied by ultrafast spectroscopy

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1495-1506 ◽  
Author(s):  
Lian Wang ◽  
Song Zhang ◽  
Ye Wang ◽  
Bing Zhang
Keyword(s):  
Excited State ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Excited State Absorption ◽  
Transient Absorption Spectroscopy ◽  
Femtosecond Transient Absorption ◽  
Pharmaceutically Active Compound ◽  
S2 State ◽  
Franck Condon ◽  
T State

AbstractDibenzofuran (DBF) has attracted much attention from scientists recently since it is applied as a photoluminescence material and pharmaceutically active compound. Since the polychlorinated derivatives are highly toxic and manifest photostability in the environment. Femtosecond transient absorption spectroscopy associated with quantum chemical calculations are employed to investigate the ultrafast excited state dynamics of dibenzofuran from the S2 state in 1,4-dioxane and ethanol, respectively. Following excitation at a wavelength of 266 nm, the S2 state is firstly populated in the Franck–Condon region and preserves the planar molecular structure of the ground state. The observed increase of the transient absorption spectra of the excited state within the first several picoseconds indicates a geometry relaxation occurring on the S2 potential energy surface. The subsequent kinetic traces of excited state absorption show that the S2 state in the adiabatic region decays to the S1 state through a fast internal conversion, followed by intersystem crossing to the T1 state with a decay time of tens and hundreds of picoseconds in ethanol and 1,4-dioxane, respectively. Finally, the deactivation processes from the S1 or T state are slow and take place on a time scale of about 20 ns.

Autoradiography with Isotopes Emitting Internal Conversion Electrons and Auger Electrons

1964 ◽  
Vol 2 (4) ◽  
pp. 241-262 ◽  
Author(s):  
S. Forberg ◽  
E. Odeblad ◽  
R. Söremark ◽  
S. Ullberg
Keyword(s):  
Internal Conversion ◽  
Auger Electrons ◽  
Conversion Electrons ◽  
Internal Conversion Electrons

scholarly journals Serum Metabolomics Identifies Altered Bioenergetics, Signaling Cascades in Parallel with Exposome Markers in Crohn’s Disease

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 449 ◽  
Author(s):  
Yunjia Lai ◽  
Jingchuan Xue ◽  
Chih-Wei Liu ◽  
Bei Gao ◽  
Liang Chi ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
High Resolution Mass Spectrometry ◽  
Signaling Cascades ◽  
Compound Identification ◽  
Serum Samples ◽  
Therapy Assessment ◽  
Integral Role ◽  
Important Pathway ◽  
Biomarker Research

: Inflammatory bowel disease (IBD) has stimulated much interest due to its surging incidences and health impacts in the U.S. and worldwide. However, the exact cause of IBD remains incompletely understood, and biomarker is lacking towards early diagnostics and effective therapy assessment. To tackle these, the emerging high-resolution mass spectrometry (HRMS)-based metabolomics shows promise. Here, we conducted a pilot untargeted LC/MS metabolomic profiling in Crohn’s disease, for which serum samples of both active and inactive cases were collected, extracted, and profiled by a state-of-the-art compound identification workflow. Results show a distinct metabolic profile of Crohn’s from control, with most metabolites downregulated. The identified compounds are structurally diverse, pointing to important pathway perturbations ranging from energy metabolism (e.g., β-oxidation of fatty acids) to signaling cascades of lipids (e.g., DHA) and amino acid (e.g., L-tryptophan). Importantly, an integral role of gut microbiota in the pathogenesis of Crohn’s disease is highlighted. Xenobiotics and their biotransformants were widely detected, calling for massive exposomic profiling for future cohort studies as such. This study endorses the analytical capacity of untargeted metabolomics for biomarker development, cohort stratification, and mechanistic interpretation; the findings might be valuable for advancing biomarker research and etiologic inquiry in IBD.

scholarly journals The internal conversion of gamma-rays.—Part II

1928 ◽  
Vol 121 (787) ◽  
pp. 447-456
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Wave Equation ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Scalar Potential ◽  
X Ray ◽  
Electro Magnetic Field ◽  
Γ Rays ◽  
Electro Magnetic

In a previous paper the absorption of γ-rays in the K-X-ray levels of the atom in which they are emitted was calculated according to the Quantum Mechanics, supposing the γ-rays to be emitted from a doublet of moment f ( t ) at the centre of the atom. The non-relativity wave equation derived from the relativity wave equation for an electron of charge — ε moving in an electro-magnetic field of vector potential K and scalar potential V is h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV + ih ε/μ c (K. grad)) ϕ = 0. (1) Suppose, however, that K involves the space co-ordinates. Then, (K. grad) ϕ ≠ (grad . K) ϕ , and the expression (K . grad) ϕ is not Hermitic. Equation (1) cannot therefore be the correct non-relativity wave equation for a single electron in an electron agnetic field, and we must substitute h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV) ϕ + ih ε/ c ((K. grad) ϕ + (grad. K) ϕ ) = 0. (2)

Lattice effect in solid state internal conversion

2009 ◽  
Vol 79 (3) ◽  
Author(s):  
Péter Kálmán ◽  
Tamás Keszthelyi
Keyword(s):  
Solid State ◽  
Internal Conversion ◽  
Lattice Effect

scholarly journals Gossip about Coronavirus: Infection status and norm adherence shape social responses

2021 ◽  
Vol 24 (4) ◽  
pp. 658-679
Author(s):  
Terence D. Dores Cruz ◽  
Romy van der Lee ◽  
Bianca Beersma
Keyword(s):  
Social Exclusion ◽  
Behavioral Intentions ◽  
Infection Risk ◽  
Infection Status ◽  
Social Responses ◽  
Social Distancing ◽  
Important Pathway ◽  
Group Members ◽  
Coronavirus Infection

To stop the spread of the Coronavirus, people must avoid infection risk. Given widespread skepticism regarding information concerning the Coronavirus received from authorities, one potentially important pathway to estimate the infectiousness of one’s group members could be through gossip (i.e., information about an absent target). Infection risk is reflected by both infection status and adherence to social distancing norms. In hypothetical scenarios ( N = 837), participants received gossip that we manipulated to describe a group member’s infection status and/or norm adherence. Results showed people tended to believe gossip and that gossip influenced behavioral intentions to avoid and punish targets of gossip as well as the perception of targets. We conclude that gossip, while potentially unreliable, could affect how people treat group members. We discuss how gossip could alleviate the Coronavirus crisis by contributing to slowing the Coronavirus’s spread, as well as exacerbate it through increased social exclusion based on unverified information.

scholarly journals Androgen Receptor Signaling in Prostate Cancer Genomic Subtypes

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3272
Author(s):  
Lauren K. Jillson ◽  
Gabriel A. Yette ◽  
Teemu D. Laajala ◽  
Wayne D. Tilley ◽  
James C. Costello ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Targeted Therapies ◽  
Meta Analysis ◽  
Therapy Resistance ◽  
Androgen Receptor Signaling ◽  
Genomic Changes ◽  
Risk Patients ◽  
Important Pathway ◽  
Therapy Option

While many prostate cancer (PCa) cases remain indolent and treatable, others are aggressive and progress to the metastatic stage where there are limited curative therapies. Androgen receptor (AR) signaling remains an important pathway for proliferative and survival programs in PCa, making disruption of AR signaling a viable therapy option. However, most patients develop resistance to AR-targeted therapies or inherently never respond. The field has turned to PCa genomics to aid in stratifying high risk patients, and to better understand the mechanisms driving aggressive PCa and therapy resistance. While alterations to the AR gene itself occur at later stages, genomic changes at the primary stage can affect the AR axis and impact response to AR-directed therapies. Here, we review common genomic alterations in primary PCa and their influence on AR function and activity. Through a meta-analysis of multiple independent primary PCa databases, we also identified subtypes of significantly co-occurring alterations and examined their combinatorial effects on the AR axis. Further, we discussed the subsequent implications for response to AR-targeted therapies and other treatments. We identified multiple primary PCa genomic subtypes, and given their differing effects on AR activity, patient tumor genetics may be an important stratifying factor for AR therapy resistance.

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