CSF Bypass Surgery in Children with Hydrocephalus: Modern Possibilities, Prospects and Ways of Solving the Correction of Complications

The chapter discusses modern and promising approaches to the use of CSF shunting operations in children. CSF shunting operations remain the only effective method for correcting persistent CSF circulation disorders in CSF resorption disorders with the development of intracranial hypertension and hydrocephalus. The chapter is devoted to general ideas about CSF dynamics and biomechanical properties of the craniospinal system that affect CSF dynamics, and gives a pathogenetic assessment of CSF dynamics in the development of intracranial hypertension and hydrocephalus. Aspects of genetics and genomics of anomalies in hydrocephalus are touched upon. Pathological changes in the brain around old ventricular shunts are described. The authors consider the types of CSF shunting operations for hydrocephalus in children. Possible complications of CSF shunting operations are analyzed with the algorithm for their correction and management tactics for this group of patients

Unsupported Ni—Mo—W Hydrotreating Catalyst: Influence of the Atomic Ratio of Active Metals on the HDS and HDN Activity

Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary for heavier feedstock to be processed. Unsupported catalysts could solve this problem, because they contain the greatest amount of sulfide active sites, which significantly increase catalysts’ activity. Unfortunately, most of the information on the preparation and properties of unsupported catalysts is devoted to powder systems, while industrial plants require granular catalysts. Therefore, the present work describes a method for the preparation of granular Ni—Mo—W unsupported hydrotreating catalysts and studies the influence of the Ni/Mo/W atomic ratio on their properties. Catalysts have been prepared by plasticizing Ni—Mo—W precursor with aluminum hydroxide followed by granulation and drying stages. Ni—Mo—W precursor and granular catalysts were studied by X-ray diffraction (XRD), nitrogen adsorption–desorption method, high-resolution transmission electron microscopy (HRTEM), and thermal analysis. Granular catalysts were sulfided through a liquid-phase sulfidation procedure and tested in hydrotreating of straight-run vacuum gasoil. It was shown that the Ni/Mo/W atomic ratio influenced the formation and composition of active compounds and had almost no influence on the textural properties of catalysts. The best hydrodesulfurization (HDS) activity was obtained for the catalyst with Ni/Mo/W ratio—1/0.15/0.85, while hydrodenitrogenation (HDN) activity of the catalysts is very similar

Unsupported Ni—Mo—W Hydrotreating Catalyst: Influence of the Atomic Ratio of Active Metals on the HDS and HDN Activity

Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary for heavier feedstock to be processed. Unsupported catalysts could solve this problem, because they contain the greatest amount of sulfide active sites, which significantly increase catalysts’ activity. Unfortunately, most of the information on the preparation and properties of unsupported catalysts is devoted to powder systems, while industrial plants require granular catalysts. Therefore, the present work describes a method for the preparation of granular Ni—Mo—W unsupported hydrotreating catalysts and studies the influence of the Ni/Mo/W atomic ratio on their properties. Catalysts have been prepared by plasticizing Ni—Mo—W precursor with aluminum hydroxide followed by granulation and drying stages. Ni—Mo—W precursor and granular catalysts were studied by X-ray diffraction (XRD), nitrogen adsorption–desorption method, high-resolution transmission electron microscopy (HRTEM), and thermal analysis. Granular catalysts were sulfided through a liquid-phase sulfidation procedure and tested in hydrotreating of straight-run vacuum gasoil. It was shown that the Ni/Mo/W atomic ratio influenced the formation and composition of active compounds and had almost no influence on the textural properties of catalysts. The best hydrodesulfurization (HDS) activity was obtained for the catalyst with Ni/Mo/W ratio—1/0.15/0.85, while hydrodenitrogenation (HDN) activity of the catalysts is very similar

Optimal Choice of the Preparation Procedure and Precursor Composition for a Bulk Ni–Mo–W Catalyst

Among the known synthesis procedures and reagents for unsupported Ni–Mo–W catalysts, there is no consensus about optimal preparation conditions of their precursors. In the present work, Ni–Mo–W precursors were prepared via three preparation techniques—hydrothermal synthesis, precipitation method and spray drying—after the synthesis of complex compounds in solution. Ni–Mo–W precursors were studied by the XRD analysis, SEM methods, Raman and UV-vis spectroscopies and XPS measurements and used for the hydrotreatment of straight-run gasoil. Precursors prepared by hydrothermal synthesis contain particles with stacked plate shapes, while other methods provide spherical particles. The formation of different amounts of individual molybdates, tungstates or mixed phases such as W1−xMoxO3 possibly doped by Ni was detected. The precipitation technique results in the formation of spheres, with W located at the center and is unavailable for catalysis. The catalytic activity increased when all active metals are available for the feedstock, and a more mixed phase containing Ni, Mo and W is formed. This mixed phase is realized when the synthesis of the Ni–Mo–W precursors is carried out in solution followed by spray drying. The resulting catalyst has 1.2–4 times higher activity than catalysts prepared by other methods

"Flora of Russia" on iNaturalist: a dataset

The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people are involved in the data collection.Within 20 months the participants accumulated over 750,000 photo observations of 6,853 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 85% of all project data are available under free licenses (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities

"Flora of Russia" on iNaturalist: a dataset

The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people are involved in the data collection.Within 20 months the participants accumulated over 750,000 photo observations of 6,853 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 85% of all project data are available under free licenses (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities

"Flora of Russia" on iNaturalist: a dataset

The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people are involved in the data collection.Within 20 months the participants accumulated over 750,000 photo observations of 6,853 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 85% of all project data are available under free licenses (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities