Refine
Year of publication
- (1)
- 2016 (1)
Document Type
- Article (1)
- Doctoral Thesis (1)
Keywords
- - (1)
- Bose-Einstein-Kondensation (1)
- Exziton (1)
- Polaron (1)
- Quantendot (1)
- chemerin (1)
- orosomucoid (1)
- overweight (1)
- periodontitis (1)
- retinolâbinding protein 4 (1)
Institute
Nanoengineering and laser optics allow for the fabrication of a wide range of systems that subject fermionic particles to geometric restrictions. In addition to strong correlations, the fermions may couple to internal or external bosonic fields, such as quantized lattice vibrations or light fields. This thesis considers the theoretical description of two such systems. One is a molecular junction, i.e., a small organic molecule contacted by metallic electrodes or leads. Itinerant electrons induce molecular vibrations and deformations, corresponding to phonon modes of considerable energy. The thesis investigates the effects of this local electron-phonon interaction on the electric and thermoelectric transport through the junction. Starting with an Anderson-Holstein quantum dot model, our ansatz is based on the application of a variational Lang-Firsov transformation that accounts for the polaronic character of the dot state. We solve the steady-state Kadanoff-Baym equations and derive a self-consistent approximation to the polaronic self-energy that accounts for finite densities and multi-phonon scattering processes. The optimal variational parameter is determined numerically by minimizing the thermodynamical potential. This allows a detailed study of the electronic dot spectral function for all interaction strengths and adiabaticity regimes. For instance, we discuss how a voltage dependent polaronic renormalization of the dot-lead coupling and the dot level causes negative differential conductance and novel conductance features. The investigation of the second system is motivated by recent experiments on the Bose-Einstein condensation of excitons in small semiconducting cuprous oxide crystals. At ultra cold temperatures three species of para- and orthoexcitons are caught in stress induced potential traps. Their decay luminescence is the primary method of detection. This thesis considers the thermodynamics of this system in terms of a multicomponent gas of weakly interacting bosons in external potentials. The coupled equations of motion are solved within a Hartree-Fock-Bogoliubov-Popov approximation. For typical experimental parameters the density distributions of the interacting species are calculated numerically. Based on the luminescence formula by Shi and Verechaka we discuss, e.g., how the spectrum of the direct decay of thermal paraexcitons may reveal the formation of a nonluminescent paraexciton condensate as well as the spatial separation of strongly repulsive orthocondensates. First results for an extended luminescence theory are presented, which takes into account the polariton effect.
Abstract
Aim
The aim of this study was to evaluate the effect of nonâsurgical periodontal therapy on circulating levels of the systemic inflammationâassociated biomarkers orosomucoid (ORM), highâsensitivity Câreactive protein (hsCRP), chemerin, and retinolâbinding protein 4 (RBP4) in overweight or normalâweight patients with periodontitis at 27.5Â months after therapy.
Materials and methods
This exploratory subanalysis includes patients from the ABPAROâtrial (ClinicalTrials.gov NCT00707369). The perâprotocol collective provided untreated periodontitis patients with high (â„28 kg/m2) or moderate (21â24 kg/m2) BMI. Out of the perâprotocol collective, 80 patients were randomly selected and stratified for BMI group, sex, and treatment group (antibiotics/placebo), resulting in 40 overweight and normalâweight patients. Patients received nonâsurgical periodontal therapy and maintenance at 3âmonth intervals. Plasma samples from baseline and 27.5 months following initial treatment were used to measure the concentrations of ORM, hsCRP, chemerin, and RBP4.
Results
At the 27.5âmonth examination, ORM and hsCRP decreased noticeably in the overweight group (ORM: p = .001, hsCRP: p = .004) and normalâweight patients (ORM: p = .007, hsCRP: p < .001). Chemerin decreased in the overweight group (p = .048), and RBP4 concentrations remained stable.
Conclusion
Nonâsurgical periodontal therapy reduced systemically elevated inflammationâassociated biomarkers in periodontitis patients. These improvements were more pronounced in overweight patients than in normalâweight patients.