Seasonal dynamics of the peroxidation enzymes’ specific activity in Salix alba leaves of the artificial stalks

Вивчено сезонну динаміку питомої активності каталази та пероксидази у листках верби білої у насадженнях по берегах р. Шпакова, що протікає у межах м. Дніпропетровськ. Виявлено залежність питомої активності оксидоредуктаз від сезону відбору проб і впливу очерету на процеси адаптації саджанців верби. Обговорюється важливість стресового впливу очерету південного на процеси адаптації саджанців верби.Изучены сезонную динамику удельной активности каталазы и пероксидазы в листьях ивы белой в насаждениях по берегам р. Шпакова, протекающей в пределах г.. Днепропетровск. Выявлена зависимость удельной активности оксидоредуктаз от сезона отбора проб и воздействия тростника на процессы адаптации саженцев ивы. Обсуждается важность стрессового воздействия тростника южного на процессы адаптации саженцев ивы.Seasonal dynamics of the specific activity of catalase and peroxidase in Salix alba L. leaves collected in the artificial stands along the Shpakova River (Dnipropetrovs’k) was studied. The seasonal dependence of oxidoreductases’ specific activity and the reed’s influence on the osier seedlings adaptation were revealed. The importance of the reeds’ stressful influence on the osier seedlings’ adaptive processes is discussed

Alumosilicate ceramic proppants based on natural refractory raw materials

The sintering-strengthening effect of the additions of the highly ferrous bauxite (with Fe[2]O[3] content of 20-25 % in the calcined state) in the compositions with refractory clays was established. It was found that in the temperature range 1350-1500°C the additions of bauxite in amounts of 10-40% have a fluxing effect due to the iron oxide introduced with bauxite in compositions with clay. An increasing the bauxite additive in the amount of 50-70% ensures its strengthening effect by increasing the total content of the mullite of the prismatic habit in the firing products of composites with clay. Preliminary clay and bauxite calcination at 900 °С and an increase in the content of bauxite additive up to 50-70% in compositions with clay allow to produce aluminosilicate proppants with a bulk density of 1.62-1.65 g/сm{3} and compressive strength up to 52 MPa

Toward an Understanding of Diamond sp²‑Defects with Unsaturated Diamondoid Oligomer Models

Nanometer-sized doubly bonded diamondoid dimers and trimers, which may be viewed as models of diamond with surface sp²-defects, were prepared from corresponding ketones via a McMurry coupling and were characterized by spectroscopic and crystallographic methods. The neutral hydrocarbons and their radical cations were studied utilizing density functional theory (DFT) and ab initio (MP2) methods, which reproduce the experimental geometries and ionization potentials well. The van der Waals complexes of the oligomers with their radical cations that are models for the self-assembly of diamondoids, form highly delocalized and symmetric electron-deficient structures. This implies a rather high degree of σ-delocalization within the hydrocarbons, not too dissimilar to delocalized π-systems. As a consequence, sp²-defects are thus also expected to be nonlocal, thereby leading to the observed high surface charge mobilities of diamond-like materials. In order to be able to use the diamondoid oligomers for subsequent surface attachment and modification, their CH-bond functionalizations were studied, and these provided halogen and hydroxy derivatives with conservation of unsaturation