Clinical and Radiographic Outcomes of Zirconia Dental Implants-A Clinical Case Series Study.

The purpose of this clinical series was to evaluate the clinical and radiographic outcomes of 20 zirconia dental implants, with a minimum follow-up of two years. Patients with at least one zirconia dental implant were included, with a mean follow-up of 34.05 months. The patient complaints such as pain and foreign body sensation, as well as clinical parameters including peri-implant infections with suppuration, implant mobility, gingival index (GI), modified plaque index (mPI), modified sulcus bleeding index (mBI), probing depth (PD) and radiological distance between the implant shoulder to the closest mesial and distal bone-to-implant contact (BIC), were assessed. All zirconia implants were successfully integrated without any pain or foreign body sensation. No mobility was detected in any of the 20 implants. Clinical examination revealed a mean PD of 2.56 mm and a radiological mean distance between the implant shoulder and the initial site of visible bone-to-implant contact (BIC) of 1.44 mm. In addition, GI, mPI and mBI indicated minimal to no inflammation. Results obtained from this series suggest that one-piece zirconia dental implants achieve good clinical and radiographic outcomes over a mean follow-up of 34 months and may be deemed a good option in patients with favorable bone conditions.

Tensor representation techniques for full configuration interaction: A Fock space approach using the canonical product format.

In this proof-of-principle study, we apply tensor decomposition techniques to the Full Configuration Interaction (FCI) wavefunction in order to approximate the wavefunction parameters efficiently and to reduce the overall computational effort. For this purpose, the wavefunction ansatz is formulated in an occupation number vector representation that ensures antisymmetry. If the canonical product format tensor decomposition is then applied, the Hamiltonian and the wavefunction can be cast into a multilinear product form. As a consequence, the number of wavefunction parameters does not scale to the power of the number of particles (or orbitals) but depends on the rank of the approximation and linearly on the number of particles. The degree of approximation can be controlled by a single threshold for the rank reduction procedure required in the algorithm. We demonstrate that using this approximation, the FCI Hamiltonian matrix can be stored with N(5) scaling. The error of the approximation that is introduced is below Millihartree for a threshold of ϵ = 10(-4) and no convergence problems are observed solving the FCI equations iteratively in the new format. While promising conceptually, all effort of the algorithm is shifted to the required rank reduction procedure after the contraction of the Hamiltonian with the coefficient tensor. At the current state, this crucial step is the bottleneck of our approach and even for an optimistic estimate, the algorithm scales beyond N(10) and future work has to be directed towards reduction-free algorithms.

Identifying stereoisomers by ab-initio calculation of secondary isotope shifts on NMR chemical shieldings.

We present ab-initio calculations of secondary isotope effects on NMR chemical shieldings. The change of the NMR chemical shift of a certain nucleus that is observed if another nucleus is replaced by a different isotope can be calculated by computing vibrational corrections on the NMR parameters using electronic structure methods. We demonstrate that the accuracy of the computational results is sufficient to even distinguish different conformers. For this purpose, benchmark calculations for fluoro(2-2H)ethane in gauche and antiperiplanar conformation are carried out at the HF, MP2 and CCSD(T) level of theory using basis sets ranging from double- to quadruple-zeta quality. The methodology is applied to the secondary isotope shifts for 2-fluoronorbornane in order to resolve an ambiguity in the literature on the assignment of endo- and exo-2-fluoronorbornanes with deuterium substituents in endo-3 and exo-3 positions, also yielding insight into mechanistic details of the corresponding synthesis.

Affective and inflammatory responses among orchestra musicians in performance situation.

A number of studies have shown that mental challenge under controlled experimental conditions is associated with elevations in inflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP). However, relatively little work has been done on the effects of 'naturalistic' stressors on acute changes in inflammatory markers. The present study examined whether perceived arousal, valence and dominance in musicians are associated with pro-inflammatory and oxidative responses to a concert situation. Blood and salivary samples obtained from 48 members of a symphony orchestra on the day of rehearsal (i.e., control situation) and on the following day of premiere concert (i.e., test situation) were used to determine changes in salivary cortisol, pro-inflammatory markers (plasma myeloperoxidase, serum CRP, plasma IL-6), oxidative stress markers (paraoxonase1 activity and malondialdehyde), and homocysteine, a risk factor for vascular disease. Results of regression analyses showed a significant trend to increased myeloperoxidase (MPO) response in individuals with low valence score. Both affective states, valence and arousal, were identified as significant predictors of cortisol response during concert. In addition, control levels of plasma malondialdehyde were positively correlated with differences in IL-6 levels between premiere and rehearsal (r=.38, p=.012), pointing to higher oxidative stress in individuals with pronounced IL-6 response. Our results indicate that stress of public performance leads to increased concentrations of plasma MPO (20%), IL-6 (27%) and salivary cortisol (44%) in musicians. The decreasing effect of pleasantness on the MPO response was highly pronounced in non-smokers (r=-.60, p<.001), suggesting a significant role of emotional valence in stress-induced secretion of MPO. Additional studies are needed to assess the generalizability of these findings to other 'naturalistic' stress situations.

Tensor decomposition in post-Hartree-Fock methods. II. CCD implementation.

In a previous publication, we have discussed the usage of tensor decomposition in the canonical polyadic (CP) tensor format for electronic structure methods. There, we focused on two-electron integrals and second order Møller-Plesset perturbation theory (MP2). In this work, we discuss the CP format for Coupled Cluster (CC) theory and present a pilot implementation for the Coupled Cluster Doubles method. We discuss the iterative solution of the CC amplitude equations using tensors in CP representation and present a tensor contraction scheme that minimizes the effort necessary for the rank reductions during the iterations. Furthermore, several details concerning the reduction of complexity of the algorithm, convergence of the CC iterations, truncation errors, and the choice of threshold for chemical accuracy are discussed.