Gutenberg Open Science (Univ. Mainz)
Not a member yet
11784 research outputs found
Sort by
Sofort- vs. Spätimplantation konischer Tissue-Level-Implantate – eine vergleichende multizentrische Studie
Get PDFVII, 66 Seiten ; Illustrationen, Diagramm
Method development and application for the analysis of chiral organic marker species in ice cores
Get PDFGlaciers are valuable environmental archives that preserve organic compounds from atmospheric aerosols that can be used as marker species for their respective emission sources. Most environmental studies do not distinguish between the enantiomers of chiral compounds, although these compounds, mostly from biogenic sources, are very common in the atmosphere. We have developed a two-dimensional (2D) liquid chromatography (mLC–LC) method that allows the simultaneous determination of the chiral ratios of the monoterpene oxidation products cis-pinic acid and cis-pinonic acid in ice-core samples. The method combines a reversed-phase column in the first dimension and a chiral column in the second dimension in a simple instrumental setup with only one additional six-port valve. This novel method was successfully applied to selected ice-core samples from the Belukha Glacier in the Siberian Altai spread over the period 1870–1970 CE. The chiral ratio of cis-pinic acid showed fluctuating values, while the chiral ratio of cis-pinonic acid remained more constant with an excess of the (−)-enantiomer
The effects of communication training on communication competence : a 360° evaluation
Get PDFCommunication skills training is essential in dental education, but training effects are often difficult to detect. The aim of this study was to assess the effect of communication training through 360° evaluation. To this end, 127 dental students were questioned with their treatment partners, their course assistants and their patients. 35 male and 92 female students took part in the study from April 2021 to February 2022.
The students’ self-assessment of their communication skills was carried out using a questionnaire at two different points in time. In addition, external assessments of communication skills were obtained from treatment partners, course tutors and patients at one point in time. A five-point Likert scale was available to all participants.
Our study shows that communication training in dental curriculum improves the students’ self-assessment of their communication skills. In addition, some effects were also measurable in the external assessment by the treatment partners and the course tutors. The patient survey showed very good results in both groups.
In summary a one-time communication training course significantly improves students’ self-perception of their communication skills, especially when it comes to more complex skills such as conversation structure and nonverbal communication. Treatment partners and course tutors also confirm improvements, while patients were unable to perceive any differences. The study shows that simple skills can be improved even without training, but complex skills require targeted training. However, longer training and further research are needed for sustainable behavioral changes and objective assessments
Characterisation of 40 barley genotypes regarding powdery mildew susceptibility and responses of selected genotypes to biological control agents
Get PDFVII, 165 Seiten ; Illustrationen, Diagramm
Non-equilibrium Dynamics of Disordered Quantum Many-Body Systems
Get PDFRecent advances in theoretical physics have increasingly focused on the dynamics of quantum systems with many interacting degrees of freedom, while ultracold atom platforms now enable the realization of diverse theoretical models with precise control over system parameters and advanced monitoring techniques. A prominent example is cavity quantum electrodynamics (CQED), where large atomic or molecular ensembles are coupled to high-finesse optical cavities, enabling strong interaction with confined electromagnetic modes and leading to phenomena such as the superradiant phase transition, in which atoms and photons form a coherent state. Most theoretical studies of CQED have concentrated on regimes of spatially uniform atom–cavity coupling, where collective behavior allows a description in terms of the classical dynamics of a few macroscopic variables. However, experimental capabilities now permit exploration beyond this limit, though theoretical progress is hindered by the exponential computational complexity of simulating large quantum systems, particularly when environmental coupling is included. This thesis addresses such challenges by developing efficient approaches, within the Keldysh formalism of non-equilibrium quantum field theory, to study systems with strongly disordered interactions coupled to external reservoirs. Two representative models are considered: a disordered spin–boson model describing light–matter interactions with quenched disorder, relevant to recent CQED experiments in confocal cavities, and a fermion–phonon system governed by the Yukawa–Sachdev–Ye–Kitaev (Yukawa-SYK) model. Both systems are quantum critical, exhibiting a continuum of low-energy modes above their stationary states, yet disorder produces qualitatively distinct dynamical behaviors: in the spin–boson system it induces slow, glassy relaxation, whereas in the Yukawa-SYK model it leads to rapid thermalization. These contrasting outcomes reveal the non-trivial role of disorder in quantum many-body systems and motivate further investigation into its effects on non-equilibrium quantum dynamics.99 Seiten ; Illustrationen, Diagramm
Evaluation of tumor budding and poorly defined clusters as histological biomarkers in squamous cell carcinomas of the vulva
Get PDFSeveral histopathological risk factors have been examined in vulvar cancer (VC) so far. However, the prognostic relevance of morphological biomarkers such as tumor budding (TB) and poorly defined clusters (PDCs) remains to be determined. Material and Methods: We histologically analyzed the formation of peritumoral and intratumoral TB and PDCs in a cohort of 157 patients with VC. We assessed their association with clinico-pathological features and evaluated their prognostic impact in terms of the risk of local recurrence and occurrence of metastasis (Fisher’s exact test) as well as overall survival (Log-rank test). Results: We determined a distinct prognostic relevance of peritumoral TB with regard to occurrence of metastasis (Fisher’s exact test; p = 0.0415) as well as a significant reduced risk local recurrence in the group with absent intratumoral TB (Fisher’s exact test; p = 0.0004). Furthermore, we showed that patients without peritumoral budding formation had a significant superior prognosis in terms of overall survival (p = 0.0366, x2 = 4.370). Conclusions: This study shows that several new histomorphological biomarkers may serve useful in predicting the clinical course of patients with VC, identifying patients at a lower risk of developing metastases/local recurrence as well as improved overall survival
Calcium-sensitiver Rezeptor-induzierte Signaltransduktion in Endometriosezellen
Get PDFV, 85 Seiten ; Illustrationen, Diagramm
Ex vivo comparison of drilling techniques for optimizing primary stability of zirconia dental implants in different bone densities
Get PDFPurpose
The objective of this study was to investigate the primary stability of zirconia implants using varying drilling protocols, with a focus on the impact of thread cutting on insertion torque in both mixed (D2/D3) and soft (D4) bone types. The study aimed to evaluate whether reducing thread cutting could increase insertion torque and consequently improve primary stability.
Methods
Four drilling protocols were developed, each varying in the degree of thread cutting: no thread cut, one-third thread cut, two-thirds thread cut, and full thread cut. Implants were placed into fresh porcine hip and tibia bones simulating D2/D3 and D4 bone. The protocols followed each implant system’s manufacturer recommendations. Insertion torque was measured using a torque indicator, and statistical analysis was conducted with the Mann-Whitney U test, with p < 0.05 considered statistically significant.
Results
Significant differences in primary stability were observed between implant systems and drilling protocols, particularly in D4 bone. Three of the four implant systems showed improved primary stability in D4 bone when the thread cut was reduced (p < 0.05). One system achieved the recommended insertion torque with a full thread cut. In contrast, in D2/D3 bone, all implant systems required a full thread cut to remain within the manufacturer’s torque guidelines.
Conclusions
Zirconia implant systems exhibit substantial variability in primary stability based on the selected drilling protocol and bone quality. Reducing thread cutting demonstrated improved stability in soft bone. However, excessive torque should be avoided to prevent mechanical failure, especially in systems with lower fracture resistance
Searching for dark matter with a spin-based interferometer
Get PDFAxion-like particles (ALPs) arise from well-motivated extensions to the Standard Model and could account for dark matter. ALP dark matter would manifest as a field oscillating at an (as of yet) unknown frequency. The frequency depends linearly on the ALP mass and plausibly ranges from 10−22 to 10 eV/c2. This motivates broadband search approaches. We report on a direct search for ALP dark matter with an interferometer composed of two atomic K-Rb-3He comagnetometers, one situated in Mainz, Germany, and the other in Kraków, Poland. We leverage the anticipated spatio-temporal coherence properties of the ALP field and probe all ALP-gradient-spin interactions covering a mass range of nine orders of magnitude. No significant evidence of an ALP signal is found. We thus place new upper limits on the ALP-neutron, ALP-proton and ALP-electron couplings reaching below gaNN < 10−9 GeV−1, gaPP < 10−7 GeV−1 and gaee < 10−6 GeV−1, respectively. These limits improve upon previous laboratory constraints for neutron and proton couplings by up to three orders of magnitude
6-Chloro-3-[4-(hexyloxy)phenyl]-[1,2,4]triazolo[4,3-b]pyridazine
Get PDFMolecules of the title compound, C17H19ClN4O, are essentially planar, the dihedral angles between the planes of the tetraazaindene ring system and the benzene ring and between the benzene ring and the hexyloxy chain being 1.56 (10)° and 5.02 (17)°, respectively. In the crystal, pairs of molecules are connected via π–π interactions between the phenyl ring and the triazolopyridazine moiety