Improving the Sensitivity of Screening Mammography in the South of the Netherlands

In this thesis I explore several factors that influence the sensitivity of screening mammography, with the aim to improve screening outcome in the southern breast cancer screening region of the Netherlands. This general introduction describes: - the background and implementation of mass breast cancer screening - trends of breast cancer incidence and mortality - the debate on screening - the relevance of this thesis - screening mammography sensitivity - methods and population - the outline of this thesi

Application of time-dependent density functional theory to optical activity

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the lowest states in methyloxirane with an accuracy of about a factor of two. In the chiral fullerene C_76 the TDLDA provides a consistent description of the optical absorption spectrum, the circular dichroism spectrum, and the optical rotatory power, except for an overall shift of the theoretical spectrum.Comment: 17 pages and 13 PostScript figure

Examination of Late Palaeolithic archaeological sites in northern Europe for the preservation of cryptotephra layers

We report the first major study of cryptotephra (non-visible volcanic ash layers) on Late Palaeolithic archaeological sites in northern Europe. Examination of 34 sites dating from the Last Termination reveals seven with identifiable cryptotephra layers. Preservation is observed in minerogenic and organic deposits, although tephra is more common in organic sediments. Cryptotephra layers normally occur stratigraphically above or below the archaeology. Nearby off-site palaeoclimate archives (peat bogs and lakes <0.3 km distant) were better locations for detecting tephra. However in most cases the archaeology can only be correlated indirectly with such cryptotephras. Patterns affecting the presence/absence of cryptotephra include geographic position of sites relative to the emitting volcanic centre; the influence of past atmospherics on the quantity, direction and patterns of cryptotephra transport; the nature and timing of local site sedimentation; sampling considerations and subsequent taphonomic processes. Overall, while tephrostratigraphy has the potential to improve significantly the chronology of such sites many limiting factors currently impacts the successful application

Evaluation of National Surgical Practice for Lateral Lymph Nodes in Rectal Cancer in an Untrained Setting

Background: Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level. Methods: Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either ‘node-picking’ (the removal of an individual LLN) or ‘partial regional node dissection’ (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (≥7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those undergoing only rectal resection. Results: Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7–3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2–2.5, p = 0.874). Conclusion: Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research.</p

Systematische UV-VUV-Zirkulardichroismus-Messungen an zyklischen Molekuelen mit Synchrotronstrahlung

Systematic circular dichroism (CD) and absorption measurements (UV) on cyclic molecules in the UV-VUV region up to 9.0 eV (138 nm) were performed at the storage ring ELSA at Bonn. A 1m Seya-Namioka-monochromator with a grating of 1200 lines per mm monochromatized the linearly polarized synchrotron radiation to be converted periodically into left and right circularly polarized light by a stress-modulated CaF_2 quarter-wave plate. Quantitative calculations of the classical carbonyl-octant-rule were carried out and compared with measurements of various camphor derivatives. Comparison of the highly resolved gas phase and liquid phase spectra, along with results from theoretical calculations confirmed the predicted Rydberg character of some excited states of alkyl-substituted oxirane and thiirane. The n(O) #-&gt;# R(3d) Rydberg transitions in chiral methyloxirane and the predicted n(S) #-&gt;# #sigma#&quot;' valence transition of (S,S)-(-)-(2,3)-dimethylthiirane were detected for the first time. It could be shown that the quadrant rule for the first excited state previously verified for some chiral oxiranes also holds for (R)-(-)-1,2-epoxy-3-methyl-butane and (R)-(-)-1,2-epoxy-4-methyl-pentane. The first ns Rydberg transitions of dimethyloxirane could be fitted to a term formula. The experimental CD- and UV-spectra of (-)-(M)-1-oxa[2,2]metacyclophane and (-)-(M)-1-thia[2,2]metacyclophane are introduced and compared with calculations. Finally a systematic series of structural isomeric (2,4)-pyridinophanes using the concept of the 'rotating chromophore' is presented. (orig.)SIGLEAvailable from TIB Hannover: RN 4852(94-09) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman