Intercalation of fullerite C₆₀ with N₂ molecules. An investigation by x-ray powder diffraction

The lattice parameter a of fullerite C₆₀ intercalated with N₂ molecules is investigated in the temperature interval 6–295 K by x-ray diffraction. It is found that the interstitial molecular N₂ has a considerable effect on both the temperatures, Tc of the orientational phase transition and Tg of the orientational glass formation. Hysteresis of a(T) has been detected in the Tc and Tg regions, besides, the abrupt change in the volume over the region defining Tc. Complete intercalation of C₆₀ with N₂ molecules results in a 0.2% increase in the lattice parameter, which persists over the whole temperature range. Evidence is also obtained that the interstitial guest molecular N₂ induces a slight deformation of the cubic symmetry of the host C₆₀ lattice

Public health determinants in social context

Demographic situation at the global and regional levels is designated by social context and social mechanisms. The probability of a certain pathological state may increase under the influence of factors, most of which can be considered as socially determined. Poverty and health care limited availability are considered by the authors in the context of the risk of the formation of a marginal situation for patients with chronic diseases, which is manifested in adaptation crisis, disability of the patient in a situation of chronic disease.</p

Marginalization of health institute professional groups: societal approach

The process of institutionalization of healthcare, which is considered as one of the basic social institutions, is realized in qualitative changes in its structure. The authors note that changes in the social structure, the social differentiation increasing, crisis and dysfunctional processes in the healthcare institution in modern Russia have led to a change in status, social mobility descending and marginalization of the social and professional groups of the healthcare institute. In the authors' opinion the process of marginalization of the social and professional groups of the healthcare institute is explained by the «concept of status inconsistency» proposed by G. Lensky.</p

Alzheimer’s Drug PBT2 Interacts with the Amyloid β 1–42 Peptide Differently than Other 8-Hydroxyquinoline Chelating Drugs

Although Alzheimer’s disease (AD) was first described over a century ago, it remains the leading cause of age-related dementia. Innumerable changes have been linked to the pathology of AD; however, there remains much discord regarding which might be the initial cause of the disease. The “amyloid cascade hypothesis” proposes that the amyloid β (Aβ) peptide is central to disease pathology, which is supported by elevated Aβ levels in the brain before the development of symptoms and correlations of amyloid burden with cognitive impairment. The “metals hypothesis” proposes a role for metal ions such as iron, copper, and zinc in the pathology of AD, which is supported by the accumulation of these metals within amyloid plaques in the brain. Metals have been shown to induce aggregation of Aβ, and metal ion chelators have been shown to reverse this reaction in vitro. 8-Hydroxyquinoline-based chelators showed early promise as anti-Alzheimer’s drugs. Both 5-chloro-7-iodo-8-hydroxyquinoline (CQ) and 5,7-dichloro-2- [(dimethylamino)methyl]-8-hydroxyquinoline (PBT2) underwent unsuccessful clinical trials for the treatment of AD. To gain insight into the mechanism of action of 8HQs, we have investigated the potential interaction of CQ, PBT2, and 5,7-dibromo-8- hydroxyquinoline (B2Q) with Cu(II)-bound Aβ(1−42) using X-ray absorption spectroscopy (XAS), high energy resolution fluorescence detected (HERFD) XAS, and electron paramagnetic resonance (EPR). By XAS, we found CQ and B2Q sequestered ∼83% of the Cu(II) from Aβ(1−42), whereas PBT2 sequestered only ∼59% of the Cu(II) from Aβ(1−42), suggesting that CQ and B2Q have a higher relative Cu(II) affinity than PBT2. From our EPR, it became clear that PBT2 sequestered Cu(II) from a heterogeneous mixture of Cu(II)Aβ(1−42) species in solution, leaving a single Cu(II)Aβ(1−42) species. It follows that the Cu(II) site in this Cu(II)Aβ(1−42) species is inaccessible to PBT2 and may be less solvent-exposed than in other Cu(II)Aβ(1−42) species. We found no evidence to suggest that these 8HQs form ternary complexes with Cu(II)Aβ(1−42).Kelly L. Summers, Graham Roseman, Kevin M. Schilling, Natalia V. Dolgova, M. Jake Pushie, Dimosthenis Sokaras, Thomas Kroll, Hugh H. Harris, Glenn L. Millhauser, Ingrid J. Pickering, and Graham N. Georg