Pulmonary responses to silica dust : the influence of crystalline structures and physico-chemical properties

The inhalation of silica crystalline polymorphs leads to the development of pulmonary nodules that vary in extent and in fibrotic content. In this study, a single protocol was used to test different silica samples (i.e., 2 non-crystalline samples: one vitreous silica, one diatomaceous earth , 4 crystalline samples: one pure a-quartz ground in a wet atmosphere, one of the same quartz heated until it becomes oc-cristobalite and 2 cristobalites obtained by heating diatomaceous earth). Wistar rats received a single intra-tracheal injection of alveolar dust and were followed over a period of 3 months. The results were exploited using macroscopic examination (wet lung weight), histological examination and biochemical dosing (hydroxyproline, lipid, and silica content). The results showed that vitreous silica, diatomaceous earth, wet-ground quartz and both types of cristobalites are responsible to a greater or lesser extent for the pulmonary reaction typical of exposure to silica (i.e., nodules ); with different cellular and fibrotic surface areas for each sample. a-cristobalite (obtained from the wet-ground quartz heated to a very high temperature; 1,300 °C) leads to the formation of only small foreign-body granulomas. All crystalline minerals tested caused alveolar lipoproteinosis. It was thus concluded that the crystalline structure plays a less important role than the surface state in the formation of silicotic nodules

National and international security in contemporary changing reality. Pt. 2

Praca recenzowana / Peer-reviewed paperThis study is devoted to the new trends in research, especially in the field of security studies, including national and international security, in the evolving areas of contemporary reality. The book is addressed especially to national and internal security students, to all students undertaking research work in the widely-understood area of security, and also to the managerial staff of various units and institutions operating within the national security and defense system. The publication contains a wide range of topics that are relevant to security, and includes the following articles: Piotr Sienkiewicz – Systems analysis of security management, Mariusz Skulimowski – Military support of humanitarian operations in Pakistan, Mieczysław Bieniek – Arab Spring – Dynamic changes in the Middle East, Henryk Ćwięk – Between Germany and Russia. The Problem of Poland’s Security in the 20th and 21st Centuries in View of Europe’s Situation. Selected Problems, Michal Pružinský, Peter Varhoľák – Selected Slovak and European security contexts, Janusz Liber – Counterintelligence support to military operations, Marek Zawartka – Security of mass events regarding stadium hooliganism. Of great interest is the article of Professor Czesław Dźwigaj – My 11th of September The Paris Retrospection, in which a different perspective on international security is presented

Origin of the dispersion limit in the preparation of Ni(Co)Mo/Al2O3 and Ni(Co)Mo/TiO2 HDS oxidic precursors

Conventional alumina and titania oxidic precursors have been characterized by Raman spectroscopy after maturation, drying and calcination. The evolution of the impregnating solution has been followed and the nature of the precipitates has been determined. After impregnation of alumina 6molybdoaluminate entities (well dispersed or not) are characterized for both the NiMo and CoMo based solids. At high Mo loading, the formation of a CoMo oxyhydroxide that yields bulk cobalt molybdate upon calcination is also observed. In counterpart on TiO2 surface of the NiMo precursor, the formation of 6molybdonickelate leading to bulk nickel molybdate upon calcination is observed. The formation of well defined phases i.e. CoMoO4 and NiMoO4 was not observed on respectively titania and alumina supports, but well dispersed polyoxomolybdate was characterized at the same Mo loading

Direct Synthesis of TiO 2

Molybdenum disulfide nanoparticles supported on titania were synthesized from aqueous solutions containing Ti and Mo precursor salts by an in situ redox reaction. The synthesis involves a redox process between Ti3+ and MoS42−, which proceeds readily under mild conditions in aqueous solution. Catalysts were made in a single step, yielding amorphous catalysts with high Mo content, or in two steps to obtain MoS2 supported on well-defined TiO2 with lower Mo content. Catalysts obtained by single-step reductive coprecipitation were highly active in the hydrodesulfurization of dibenzothiophene, exceeding the activity of an alumina-supported Co–Mo reference. In contrast to alumina-supported catalysts, the addition of Co as promoter did not enhance the catalytic activity of MoS2/TiO2 to the same extent (+30 %) as for alumina-supported Co–Mo catalysts. Instead, a change in selectivity towards hydrogenolysis products at the expense of hydrogenation products was observed. It is suggested that Ti may act as a promoter for MoS2 in hydrogenation reactions

Upconverting Ho–Yb doped titanate nanotubes

The synthesis of Ho3 +–Yb3 + codoped titanate nanotubes was carried out successfully via a hydrothermal treatment method from a precursor powder. These novel nanotubes treated at RT, 100 °C and 280 °C were studied with the aim of determining their structural and optical properties. As the thermal treatment was increased, their upconversion emission becomes stronger. This behavior was related to reduction of hydroxyl groups and the water on the surface, which resulted in changes in the interlayer distances of the nanotubes