High-pressure structural phase transitions in semiconducting niobium dioxide

Niobium dioxide was studied up to 47 GPa by angle-dispersive, x-ray powder diffraction. Semiconducting α − NbO 2 (space group I 4 1 / a , Z = 32 ) was found to transform to β − NbO 2 (space group I 4 1 , Z = 16 ) above 5 GPa. Both phases have distorted rutile-type structures and the transition involves a change in the long-range ordering of the metal-metal bonds. A further transition was observed above 8 GPa to a baddeleyite-related structure with a = 9.975 ( 1 ) , b = 9.963 ( 1 ) , c = 9.933 ( 1 ) Å , β = 104.023 ( 4 ) ° , and Z = 32 at 12.8 GPa. The doubling of the unit cell along a, b, and c and the larger monoclinic angle with respect to a baddeleyite-type cell are due to the presence of metal-metal bonds. The d 1 cation dioxide, NbO 2 , is thus shown to behave in a similar way to d 0 cation dioxides, which follow a phase transition sequence involving the baddeleyite-type structure

Wüste im Mund : Best Practice Xerostomie

Einleitung: Unter Xerostomie wird eine Mundtrockenheit verstanden, die durch verminderten oder fehlenden Speichelfluss verursacht wird. Häufige Ursachen sind medikamentöse Therapien, Radiotherapie im Kopf- und Halsbereich sowie verschiedene systemische Krankheiten. 34-40% der palliativen Patient:innen mit Krebserkrankung leiden an Xerostomie. Ziel: Ziel des Posters ist es darzustellen, welche Interventionen sich zur Mundbefeuchtung bei Xerostomie-Betroffenen im palliativen Setting eignen. Methode: Es wurde eine systematisierte Literaturrecherche auf PubMed und CINAHL Complete durchgeführt. Mittels Citation Tracking wurden weitere Studien gefunden. Ergebnisse: Eine mögliche Intervention bei Xerostomie ist ein Speicheldrüsen-Stimulanz; ein Produkt, welches den Speichelfluss anregt. Der Wirkstoff Pilocarpin stimuliert die Sekretion der exokrinen Drüsen und fördert somit die Speichelproduktion. Dieser Effekt gelingt nur bei einer Restfunktion der Speicheldrüse. Weitaus häufiger kommt künstlicher Speichelersatz zum Einsatz. Die Wirkungsdauer des flüssigen Speichelersatzes beträgt meist weniger als eine Stunde. Im Vergleich zu flüssigen zeigen die Gel-Produkte eine etwas längere Wirkung. Ein Vergleich der verschiedenen Interventionen wird in der Tabelle 1 dargestellt. Diskussion / Empfehlung für die Praxis: Da kaum Studien zu Xerostomie im palliativen Setting vorhanden sind, wurde auch alternative Settings miteinbezogen. Aufgrund dem geringen Anwendungsintervall scheint Pilocarpin für Patient:innen und Pflegefachpersonen ein zielführendes Produkt zu sein. Da Xerostomie aber häufig auch in der terminalen Phase auftritt, wo das Schlucken von Tabletten nicht mehr möglich ist, und das Produkt unerwünschte systemische Wirkungen wie Nausea und Schweissausbrüche hat, ist dessen Einsatz nicht uneingeschränkt zu empfehlen. Betroffene berichten, dass die Ersatzprodukte oft einen unangenehmen Geschmack aufweisen und daher der Gebrauch von Wasser bevorzugt wird. Um das Ziel der Verbesserung der Lebensqualität zu erreichen, ist eine individuelle Anpassung der Intervention an die (Geschmacks-) Wünsche der Patient:innen notwendig. Schlussfolgerung: Die Evidenzlage ist nicht eindeutig, so dass keine der vorgestellten Interventionen klar priorisiert werden kann. Im Zentrum der Entscheidungsfindung für eine bestimmte Intervention stehen die individuellen Bedürfnisse der Betroffenen

Pressure-induced alpha-to-omega transition in titanium metal: A systematic study of the effects of uniaxial stress

We investigated the effects of uniaxial stress on the pressure-induced alpha-to-omega transition in pure titanium (Ti) by means of angle dispersive x-ray diffraction in a diamond-anvil cell. Experiments under four different pressure environments reveal that: (1) the onset of the transition depends on the pressure medium used, going from 4.9 GPa (no pressure medium) to 10.5 GPa (argon pressure medium); (2) the a and w phases coexist over a rather large pressure range, which depends on the pressure medium employed; (3) the hysteresis and quenchability of the w phase is affected by differences in the sample pressure environment; and (4) a short term laser-heating of Ti lowers the alpha-to-omega transition pressure. Possible transition mechanisms are discussed in the light of the present results, which clearly demonstrated the influence of uniaxial stress in the alpha-to-omega transition.Comment: 16 pages, 6 figures, 1 tabl

Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell

The high pressure and high temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, being the melting temperature in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston-cylinder apparatus experiments. A small slope for the melting curve of Ta is estimated (dTm/dP = 24 K/GPa at 1 bar) and a possible explanation for this behaviour is given. Finally, a P-V-T equation of states is obtained, being the temperature dependence of the thermal expansion coefficient and the bulk modulus estimated.Comment: 31 pages, 8 figures, to appear in J.Phys.:Cond.Matte

The Swiss Kidney Stone Cohort (SKSC), a longitudinal, multi-centric, observational cohort to study course and causes of kidney stone disease in Switzerland.

Kidney stone disease has a high prevalence worldwide of approximately 10 % of the population and is characterized by a high recurrence rate Kidney stone disease results from a combination of genetic, environmental, and life-style risk factors, and the dissection of these factors is complex. The Swiss Kidney Stone Cohort (SKSC) is an investigator-initiated prospective, multi-centric longitudinal, observational study in patients with kidney stones followed with regular visits over a period of 3 years after inclusion. Ongoing follow-ups by biannual telephone interviews will provide long-term outcome data up to 10 years. SKSC comprises 782 adult patients (age > 18 yrs) with either recurrent stones or a single stone event with at least one risk factor for recurrence. In addition, a control cohort of 207 individuals without kidney stone history and absence of kidney stones on a low-dose CT-scan at enrolment has also been recruited. SKSC includes extensive collections of clinical data, biochemical data in blood and 24 hr urine samples, and genetic data. Biosamples are stored at a dedicated biobank. Information on diet and dietary habits were collected through food frequency questionnaires and standardized recall interviews by trained dieticians with the Globodiet software. SKSC provides an unique opportunity and resource to further study cause and course of kidney disease in a large population with data and samples collected of a homogenous collective of patients throughout the whole Swiss population

Sozialstaatliche Kürzungspolitik in Deutschland: Nur eine Mär? Eine quantitative Gesetzgebungsanalyse 1974–2014

Quantitative analyses on welfare state dynamics have to cope with the “dependent variable problem”, as studies on social spending reach different conclusions than analyses of replacement rate data. This article suggests a way around this problem by presenting results from a fine-grained analysis of welfare state legislation in Germany between 1974 and 2014. We show that the German welfare state has seen both cuts and expansions occur in all decades. Moreover, we show by means of a regression analysis that partisan politics play a role. Supporting the “Nixon-in-China”-thesis, social democratic governments are associated with a higher probability of cutbacks – especially in times of budgetary pressure – whereas expansions are more likely under Christian democratic governments

Effects of pressure on the local atomic structure of CaWO4 and YLiF4: Mechanism of the scheelite-to-wolframite and scheelite-to-fergusonite transitions

The pressure response of the scheelite phase of CaWO4 (YLiF4) and the occurrence of the pressure induced scheelite-to-wolframite (M-fergusonite) transition are reviewed and discussed. It is shown that the change of the axial parameters under compression is related with the different pressure dependence of the W-O (Li-F) and Ca-O (Y-F) interatomic bonds. Phase transition mechanisms for both compounds are proposed. Furthermore, a systematic study of the phase transition in 16 different scheelite ABX4 compounds indicates that the transition pressure increases as the packing ratio of the anionic BX4 units around the A cations increases.Comment: 38 pages, 10 figures (Figure 5 corrected), accepted for publication in Journal of Solid State Chemistr

Mode of socio-economic development and occupational structure: the case of contemporary Russia

The given paper assumes the existence of a correlation between the occupational structure and the mode of social and economic development of a country. It is shown that the modern stage of development in advanced economies could be described by the post-industrial phase with (a) the specific proportions in the occupational structure (predominance of professional managers and technical experts); (b) particular nature of work and the corresponding extent of labor division according to specialization and qualification (highly skilled labor with broad specialization and a new criterion of creativity included within qualifications). Within the certain historical framework these indicators, combined onto the entire scheme, produce the criteria to distinct different types of socio-economic development and arrange them in consistent order. The analysis of occupational structure of Russian population shows that the reforms of 1990s have facilitated the process of deindustrialization alongside with the growth of semi- and low-skilled jobs. According to the scheme, Russia seems to have reached the stage of the development that is similar to one of the 1950–1960s in the USA and the Europe