Desmoplastic Fibroma of Radius Managed with Non-Vascularised Fibular Autograft - A Case Report.

Desmoplastic fibromas of bone are extremely rare, slow growing, locally invasive, benign primary bone tumours, bearing close resemblance to the extra-abdominal desmoid tumours of soft tissue. They typically occur in patients around 30 years of age, and most commonly affect the mandible, pelvis and meta-diaphyseal region of long bones. En bloc or wide resection has typically been the treatment of choice to avoid recurrence, however, recent reports support curettage with bone grafting and adjuvant therapy to minimise functional loss. We report a 9-year-old child with a desmoplastic fibroma of right radius. This is an unusual age group for this bone tumor. The tumor was managed with en bloc resection and reconstruction with a non-vascularised fibula autograft. The patient had good functional outcome and no recurrence at 1-year follow-up. Level of Evidence: Level V (Therapeutic).

Vibronic interaction in CO3- photo-detachment: Jahn-Teller effects beyond structural distortion and general formalisms for vibronic Hamiltonians in trigonal symmetries.

Recently, the negative ion photoelectron spectrum of CO3- was reported and the second lowest energy band is assigned to the close-lying 3E'' and 3E' states that undergo Jahn-Teller distortions (Chem. Sci., 2016, 7, 1142). This assignment is based on the Born-Oppenheimer approximation and the assumption of a static Jahn-Teller effect that distorts the CO3 structure from D3h to C2v symmetry. In this work, we employ a 4 states 6 modes vibronic coupling model to investigate the triplet band and uncover the dynamic and non-adiabatic nature of the Jahn-Teller and pseudo-Jahn-Teller interactions in the triplet states. The apparent four peaks progression in the band is studied in depth, and is found to consist of more than four transitions. By comparing the simulated spectra using the full model and the reduced-dimension 2 states 2 modes models, we characterize those transitions. The origin of the complexities of the spectrum is traced to the C-O nonbonding character of the orbitals that lose electron in the photo-detachment process. Methodology-wise, we derive and present the formalisms for arbitrary order expansions of all bimodal trigonal Jahn-Teller and pseudo-Jahn-Teller Hamiltonians in vibrational coordinates.

Semiclassical transition state theory based on fourth order vibrational perturbation theory: Model system studies beyond symmetric Eckart barrier.

The following one-dimensional model potential barriers are studied to compute the tunneling probabilities using semiclassical transition state theory (SCTST) based on fourth order vibrational perturbation theory (VPT4): (i) Morse barrier, (ii) asymmetric Eckart barrier, (iii) adjacent well barrier, and (iv) first order approximation to the symmetric Eckart barrier. The current investigation extends a previous study performed for the symmetric Eckart barrier. The performance of VPT4-SCTST is investigated for a broad range of energies, including the very deep tunneling regime (approximately 1% of the barrier height), and the results are compared to the exact quantum mechanical treatment, as well as to the popular second order vibrational perturbation theory (VPT2)-SCTST approach. While the VPT4-SCTST results are in excellent agreement with their quantum mechanical counterparts for a wide range of energies above and below the barrier, it is found for systems (ii) and (iv) that higher order terms (in n + 1 2 ) in energy expansion are important for similarly excellent agreement in the deep tunneling regime. For the asymmetric Eckart barrier, the convergence properties of SCTST are analyzed in terms of its analytically known Siegert eigenvalues. A simple empirical modification of VPT2-SCTST advocated in the aforementioned previous work for the symmetric Eckart barrier is also tested here for the new model systems, and it is shown not to provide a uniformly systematic improvement.

A proposed new scheme for vibronically resolved time-dependent photoelectron spectroscopy: pump-repump-continuous wave-photoelectron spectroscopy (prp-cw-pes).

We propose a new scheme for time-resolved photoelectron spectroscopy denoted as pump-repump-continuous wave-photoelectron spectroscopy (prp-cw-pes). This scheme is comprised of two femtosecond laser (pump) pulses under cw illumination (probe). By changing the time-delay between pump and repump lasers one can manipulate the populations of vibronic levels in electronic excited states. The cw laser acts on for a long time and establishes resonance between excited states and the continuum photo-ionized states. Sharp spectra can be obtained from the resonance condition [formula: see text]. The intensities in the spectra are sensitive to the time-delay between the pump-repump pulses, but only depend on the populations of excited states, not the phase relations (coherence). As a result, each time-delayed snapshot spectrum is a weighted sum of so-called fingerprints, where a fingerprint is the vibrationally resolved photoelectron spectrum for a single vibronic excited state. The latter information can potentially be simulated reliably using vibronic models and wave packet propagation methods. In the easiest application of the experiment, different time-delays produce different spectra, for a single molecular system. This wealth of experimental data can be fitted to an, ideally small, set of theoretical fingerprints by adjusting the populations as fitting parameters. This technique might be able to distinguish between closely related molecular species. Adopting a different viewpoint, the proposed scheme can also be employed to monitor the time-dependent dynamics by changing the phase relationship between the pump and repump laser that can be viewed as a "control mechanism" employed in wave packet interferometry. Simplifications arise as the change in the spectra is due to the changing populations, not because of the coherence. In this paper, we outline the ideas behind the scheme and illustrate the ideas theoretically using simple model systems.

Design of Small Intramolecular Singlet Fission Chromophores: An Azaborine Candidate and General Small Size Effects.

We report the first attempt to design small intramolecular singlet fission chromophores, with the aid of quantum chemistry and explicitly simulating the time evolution of state populations using quantum dynamics method. We start with three previously proposed azaborine-substituted intermolecular singlet fission chromophores. Through analyzing their frontier orbital amplitudes, we select a BN-substituted azulene as the building block. Covalently connecting two such monomers and tuning their relative configuration, we examine three dimers. One dimer is found to be an eminent candidate: the triplet-pair state is quickly formed within 1 ps, and the two triplets are ready to be disentangled. We elucidate the general small size effects in intramolecular singlet fission and focus on specific aspects which should be taken care of when manipulating the fission rate through steric hindrance.