Nucleon Sigma Terms with N_{f}=2+1 Flavors of O(a)-Improved Wilson Fermions

We present a lattice-QCD based analysis of the nucleon sigma terms using gauge ensembles with N_{f}=2+1 flavors of O(a)-improved Wilson fermions, with a complete error budget concerning excited-state contaminations, the chiral interpolation as well as finite-size and lattice spacing effects. We compute the sigma terms determined directly from the matrix elements of the scalar currents. The chiral interpolation is based on SU(3) baryon chiral perturbation theory using the extended on-mass shell renormalization scheme. For the pion nucleon sigma term, we obtain σ_{πN}=(43.7±3.6)  MeV, where the error includes our estimate of the aforementioned systematics. The tension with extractions based on dispersion theory persists at the 2.4-σ level. For the strange sigma term, we obtain a nonzero value, σ_{s}=(28.6±9.3)  MeV.

Strange Electromagnetic Form Factors of the Nucleon with N_{f}=2+1 O(a)-Improved Wilson Fermions

We present results for the strange contribution to the electromagnetic form factors of the nucleon computed on the coordinated lattice simulation ensembles with N_{f}=2+1 flavors of O(a)-improved Wilson fermions and an O(a)-improved vector current. Several source-sink separations are investigated in order to estimate the excited-state contamination. We calculate the form factors on six ensembles with lattice spacings in the range of a=0.049-0.086  fm and pion masses in the range of m_{π}=200-360  MeV, which allows for a controlled chiral and continuum extrapolation. In the computation of the quark-disconnected contributions, we employ hierarchical probing as a variance-reduction technique.

Balancing the role of the dental school in teaching, research and patient care; including care for underserved areas

Inequalities within dentistry are common and are reflected in wide differences in the levels of oral health and the standard of care available both within and between countries and communities. Furthermore there are patients, particularly those with special treatment needs, who do not have the same access to dental services as the general public. The dental school should aim to recruit students from varied backgrounds into all areas covered by the oral healthcare team and to train students to treat the full spectrum of patients including those with special needs. It is essential, however, that the dental student achieves a high standard of clinical competence and this cannot be gained by treating only those patients with low expectations for care. Balancing these aspects of clinical education is difficult. Research is an important stimulus to better teaching and better clinical care. It is recognized that dental school staff should be active in research, teaching, clinical work and frequently administration. Maintaining a balance between the commitments to clinical care, teaching and research while also taking account of underserved areas in each of these categories is a difficult challenge but one that has to be met to a high degree in a successful, modern dental school.

Universality of the rho meson coupling in effective field theory

It is shown that both the universal coupling of the rho meson and the Kawarabayashi-Suzuki-Riadzuddin-Fayyazuddin expression for the magnitude of its coupling constant follow from the requirement that chiral perturbation theory of pions, nucleons, and rho mesons is a consistent effective field theory. The prerequisite of the derivation is that all ultraviolet divergences can be absorbed in the redefinition of fields and the available parameters of the most general effective Lagrangian.

Comparison of S100 protein and MIA protein as serum marker for malignant melanoma

BACKGROUND

Detection of S100 beta in serum has been shown to be a significant prognostic marker for malignant melanoma in earlier studies. Melanoma inhibiting activity (MIA) has recently been detected as a new serum marker for malignant melanoma.

MATERIALS AND METHODS

In the present study, serum levels of S100 beta protein and MIA were measured over a time period of up to 18 months in 271 serum samples from 65 melanoma patients at different stages of disease, during chemotherapy and/or immunotherapy. In addition, 46 sera of control patients were analysed. The aim of this study was to compare both potential markers. S100 beta was measured using the immunoluminometric assay LIA-mat Sangtec (Byk Sangtec Diagnostica) with a cut-off level of 0.12 microgram/l. MIA was determined by the MIA ELISA kit (Roche) using a cut-off level of 6.5 ng/ml.

RESULTS

In 53 patients a direct correlation of S-100 values and clinical course could be observed (81.5%), whereas in 48 patients MIA-values and clinical course (73.8%) showed an association. S100 beta levels were incorrectly elevated in 5 out of 25 sera, "false positive" (20%)) and were in 8 out of 40 sera not elevated despite the detection of metastases "false negative" (20%)). Assessing the MIA levels, 2 out of 25 probes were false positive (8%) and 13 out of 40 probes false negative(32.5%).

CONCLUSION

Our data strongly suggest that S100 and MIA represent serum tumor markers that are valuable both in therapy-monitoring and in detection of tumour progression.

Guided tissue regeneration around dental implants in immediate extraction sockets: comparison of e-PTFE and a new titanium membrane

To evaluate the efficacy of guided tissue regeneration around exposed implant threads, 16 implants were placed into fresh extraction sockets in beagle dogs. Polytetrafluoroethylene (e-PTFE) membranes and titanium membranes were used to cover the defects around implants. A control group did not receive any membranes. Results were evaluated histologically. The average gain in bone height was 2.1 mm for e-PTFE sites, 0.8 mm for titanium membranes, and 2.9 mm for control sites. The greatest gain in bone levels was seen for two sites that received e-PTFE membranes and remained covered for the entire evaluation interval. Within the limits of this study, clinical and histologic evidence demonstrated that, when primary coverage is maintained, the use of e-PTFE membranes can significantly enhance bone regeneration around implants.