Whole brain MP2RAGE-based mapping of the longitudinal relaxation time at 9.4T.

Mapping of the longitudinal relaxation time (T1) with high accuracy and precision is central for neuroscientific and clinical research, since it opens up the possibility to obtain accurate brain tissue segmentation and gain myelin-related information. An ideal, quantitative method should enable whole brain coverage within a limited scan time yet allow for detailed sampling with sub-millimeter voxel sizes. The use of ultra-high magnetic fields is well suited for this purpose, however the inhomogeneous transmit field potentially hampers its use. In the present work, we conducted whole brain T1 mapping based on the MP2RAGE sequence at 9.4T and explored potential pitfalls for automated tissue classification compared with 3T. Data accuracy and T2-dependent variation of the adiabatic inversion efficiency were investigated by single slice T1 mapping with inversion recovery EPI measurements, quantitative T2 mapping using multi-echo techniques and simulations of the Bloch equations. We found that the prominent spatial variation of the transmit field at 9.4T (yielding flip angles between 20% and 180% of nominal values) profoundly affected the result of image segmentation and T1 mapping. These effects could be mitigated by correcting for both flip angle and inversion efficiency deviations. Based on the corrected T1 maps, new, 'flattened', MP2RAGE contrast images were generated, that were no longer affected by variations of the transmit field. Unlike the uncorrected MP2RAGE contrast images acquired at 9.4T, these flattened images yielded image segmentations comparable to 3T, making bias-field correction prior to image segmentation and tissue classification unnecessary. In terms of the T1 estimates at high field, the proposed correction methods resulted in an improved precision, with test-retest variability below 1% and a coefficient-of-variation across 25 subjects below 3%.

[Why Strive after Clinical Social Medicine? From Epidemiological Association to Personalized Social Medicine: a Case of Breast Cancer Care]. / Klinische Sozialmedizin - Warum? Von der epidemiologischen Assoziation zur personalisierten Sozialmedizin am Beispiel der Versorgung bei Mammakarzinom.

Advances in biomedicine, especially molecular biology and genetics, gave rise to the concept of personalized medicine targeting the patient's individual characteristics and needs to ensure the best possible therapy and healthcare. This concept, however, can be successfully implemented only if due consideration is given to (psycho-)social factors, as is shown for instance by considerably reduced post-therapy survival rates among cancer patients in regions with lower socioeconomic status, How breast cancer patients, for instance, find their way back to daily life and work after initial treatment at a breast center is substantially determined by multiple factors going beyond pure medical care. These factors critically affect health status and therapy outcomes, but are missing in current research agenda. A profound expertise in social medicine is required to respond in ways tailored to the individual's healthcare needs that go beyond just medical therapy. This expertise comprises, in particular, knowledge of inequality of access to healthcare due to varying health competence that in turn, results in inequality of health outcome and care. Competence in social medicine both in the clinic and outpatient care can help to individually target negative factors that originate from the social environment as well as from deficits in communication and coordination in the healthcare system and have an effect on the health status of patients..This, however, requires institutionalization of (clinical) social medicine and in particular, better opportunities for advanced training in social medicine in clinical departments and outpatient units.

Communities of bacteria and viruses in waters of the Gulf of Ob and Taz Estuary.

The study of the most abundant components in freshwater plankton in the Gulf of Ob and Taz Estuary in the summer-autumn season has demonstrated that the abundance and biomass of bacteria are stable and typical for mesotrophic waters during active microalgae vegetation. The abundance of viral particles varies in the range which is reported for unproductive or medium-productive water bodies. The environmental factors affecting affect the development and patterns of bacterio- and virioplankton distribution are considered.

[Health status evaluation in children]. / Ob otsenke zdorov'ia detei.

A dependence of a health status on a condition of adaptation and of functional reserves of child's organism was studied. It was shown that the health status of contemporary schoolchildren is characterized, alongside with a higher prevalence of poly-organs' and morphological-and-functional deviations and chronic pathologies, by impaired rates and a lack of harmonic physical development as well as by a low level of reserve organism abilities. A variety of measures is suggested to promote the existing system of physical education.

Motion extrapolation and velocity transposition.

A study of the effect of the size of a moving target and the extent of its visible motion on motion extrapolation is reported. Targets (a horizontal pair of dots separated by either 0.2 or 0.8 deg) moved across a 10 deg rectilinear path and were then occluded. Observers pressed a key when they thought the leading dot of a hidden target had reached a randomly specified position (0-12 deg from the point of occlusion). In experiment 1, in agreement with velocity-transposition predictions, at moderate (5 deg s-1) and rapid (10 deg s-1) velocities extrapolation times were longer for large targets than for small ones. At slow velocity (2.5 deg s-1) this effect was reversed. In experiment 2 the effect of target size at moderate velocity was found for a short (2.5 deg) visible path. However, the extrapolation time increased with shorter (2.5 deg versus 10 deg) paths. A proposed account of these effects suggests that the visual system performs a spatiotemporal scaling, according to the velocity-transposition principle, not only of visible motion but also of extrapolated motion.