Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines

We are presenting the electronic photo fragment spectra of the protonated pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well structured vibrational progression, while protonated monomer shows broad vibrational bands. This shows that proton bonding can block some non radiative processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the LUMAT federation (FR LUMAT 2764

Ion-Induced Dipole Interactions and Fragmentation Times : Cα\alpha -Cβ\beta Chromophore Bond Dissociation Channel

The fragmentation times corresponding to the loss of the chromophore (C$\alpha$-- C$\beta$ bond dissociation channel) after photoexcitation at 263 nm have been investigated for several small peptides containing tryptophan or tyrosine. For tryptophan-containing peptides, the aromatic chromophore is lost as an ionic fragment (m/z 130), and the fragmentation time increases with the mass of the neutral fragment. In contrast, for tyrosine-containing peptides the aromatic chromophore is always lost as a neutral fragment (mass = 107 amu) and the fragmentation time is found to be fast (\textless{}20 ns). These different behaviors are explained by the role of the postfragmentation interaction in the complex formed after the C$\alpha$--C$\beta$ bond cleavage

The first HyDRA challenge for computational vibrational spectroscopy

Vibrational spectroscopy in supersonic jet expansions is a powerful tool to assess molecular aggregates in close to ideal conditions for the benchmarking of quantum chemical approaches. The low temperatures achieved as well as the absence of environment effects allow for a direct comparison between computed and experimental spectra. This provides potential benchmarking data which can be revisited to hone different computational techniques, and it allows for the critical analysis of procedures under the setting of a blind challenge. In the latter case, the final result is unknown to modellers, providing an unbiased testing opportunity for quantum chemical models. In this work, we present the spectroscopic and computational results for the first HyDRA blind challenge. The latter deals with the prediction of water donor stretching vibrations in monohydrates of organic molecules. This edition features a test set of 10 systems. Experimental water donor OH vibrational wavenumbers for the vacuum-isolated monohydrates of formaldehyde, tetrahydrofuran, pyridine, tetrahydrothiophene, trifluoroethanol, methyl lactate, dimethylimidazolidinone, cyclooctanone, trifluoroacetophenone and 1-phenylcyclohexane-cis-1,2-diol are provided. The results of the challenge show promising predictive properties in both purely quantum mechanical approaches as well as regression and other machine learning strategies

Second site mutagenesis of a hypomorphic ago1 allele identifies SKI3 as an endogenous suppressor of PTGS

Second site mutagenesis was performed on the ago1-33 hypomorphic mutant, which exhibits reduced sense transgene post-transcriptional gene silencing (S-PTGS). Mutations in FRY1, a positive regulator of the cytoplasmic 5'-to-3' exoribonuclease XRN4, and in SKI3, a member of the SKI complex that threads RNAs directly to the 3'-to-5' exoribonuclease of the cytoplasmic exosome, compensated AGO1 partial deficiency and restored S-PTGS with 100% efficiency. Moreover, xrn4 and ski3 single mutations provoked the entry of non-silenced transgenes into S-PTGS and enhanced S-PTGS on partially silenced transgenes, indicating that cytoplasmic 5'-to-3' and 3'-to-5' RNA degradation generally counteract S-PTGS, likely by reducing the amount of transgene aberrant RNAs that are used by the S-PTGS pathway to build up siRNAs that guide transgene RNA cleavage by AGO1. Constructs generating improperly terminated transgene mRNAs were not more sensitive to ski3 or xrn4 than regular constructs, suggesting that improperly terminated transgene mRNAs not only are degraded from both the 3' end but also from the 5' end, likely after decapping. The fact that impairment of either 5'-to-3' or 3'-to-5' RNA degradation is sufficient to provoke the entry of transgene RNA into the S-PTGS pathway whereas simultaneously impairment of both pathways is necessary to provoke the entry of endogenous mRNA into the S-PTGS pathway suggest poor RNA quality upon transcription of transgenes integrated at random genomic locations

Outcomes after anterior cervical discectomy and fusion in professional athletes

BACKGROUND:: Significant controversy exists regarding when an athlete may return to contact sports after anterior cervical discectomy and fusion (ACDF). Return-to-play (RTP) recommendations are complicated due to a mix of medical factors, social pressures, and limited outcome data. OBJECTIVE:: The aim of this study was to characterize our diagnostic and surgical criteria, intervention, postoperative imaging results, and rehabilitation and report RTP decisions and outcomes for professional athletes with cervical spine injuries. METHODS:: Fifteen professional athletes who had undergone a 1-level ACDF by a single neurosurgeon were identified after a retrospective chart and radiographic review from 2003 to 2012. Patient records and imaging studies were recorded. RESULTS:: Seven of the 15 athletes presented with neurapraxia, 8 with cervical radiculopathy, and 2 with hyperintensity of the spinal cord. Cervical stenosis with effacement of the cerebrospinal fluid signal was noted in 14 subjects. The operative level included C3-4 (4 patients), C4-5 (1 patient), C5-6 (8 patients), and C6-7 (2 patients). All athletes were cleared for RTP after a neurological examination with normal findings, and radiographic criteria for early fusion were confirmed. Thirteen of the 15 players returned to their sport between 2 and 12 months postoperatively (mean, 6 months), with 8 still participating. The RTP duration of the 5 who retired after full participation ranged from 1 to 3 years. All athletes remain asymptomatic for radicular or myelopathic symptoms or signs. CONCLUSION:: After a single-level ACDF, an athlete may return to contact sports if there are normal findings on a neurological examination, full range of neck movement, and solid arthrodesis. There may be an increased risk of the development of adjacent segment disease above or below the level of fusion. Cord hyperintensity may not necessarily preclude RTP