Selection of serum deproteinization methods

Dentists are often called upon to perform painful procedures on children. This may present a management problem for the practitioner who is unfamiliar with accepted behavioural management techniques or prescribing analgesics for paediatric patients. This article will review techniques that may be used to guide a child patient's behaviour through painful procedures as well as addressing the need for post-operative analgesics in the paediatric population.     

Erbium ion electroluminescence in p ++/n +/n-Si:Er/n ++ silicon diode structures

Results of experimental studies of erbium ion electroluminescence in p ⁺⁺/n ⁺/n-Si:Er/n ⁺⁺ silicon diode structures grown by sublimation molecular-beam epitaxy are discussed. The distinctive feature of these structures is that the regions of electron flux formation of (n ⁺-Si) and impact excitation of erbium ions (n-Si:Er) are spaced. The influence of the n ⁺-Si layer thickness on electrical and electroluminescent properties of diodes was studied. It was shown that n ⁺-Si layer thinning causes the transformation of the structure breakdown mechanism from tunneling to avalanche. The dependence of the Er³⁺ ion electroluminescence on the thickness of the heavily doped n ⁺-Si region is bell-shaped. At the n ⁺-Si-layer doping level n ≈ 2 × 10¹⁸ cm^?3, the maximum electroluminescence intensity is attained at an n ⁺-Si layer thickness of ～23 nm.     

Structure and processes of formation of oxide electrocatalysts

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 27–29, October, 1991.     

Lanthanum Extraction from Chloride-Acetate Solutions in Systems with Mixtures of Cyanex 272 and Caprylic Acid

Theoretical Foundations of Chemical Engineering - Lanthanum extraction from chloride-acetate solutions using mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) and caprylic acid in...     

The Influence of the Shape of Model Hydrometeors on the Formation of Discharge between an Artificial-Thunderstorm Cell and the Ground

We have experimentally studied how arrays of model coarse hydrometeors influence the initiation and propagation of discharge between an artificial-thunderstorm cell of negative or positive polarity and the ground. It is established for the first time that the probability of initiation and stimulation of a channeled discharge between negatively or positively charged cloud and the ground significantly depends on the shape and size of coarse hydrometeors occurring near the thunderstorm cell boundaries. The obtained results can be used in developing methods for the artificial initiation of the cloud–ground type lightning of both polarities and targeted discharge of thunderstorm clouds.     

Phase Composition,Structure, and Hydrolytic Durability of a Uranium-Containing Magnesium Potassium Phosphate Compound

Uranium-containing samples of magnesium potassium phosphate (MPP) compound were synthesized using a nitric acid uranium solution. Uranium is incorporated in the MPP compound in the form of potassium uranyl phosphate with the structure of metaankoleite natural mineral, K(UO₂)PO₄·3H₂O. The differential and integral uranium leach rates, determined in accordance with GOST (State Standard) R 52 126–2003 on the 28th day of contact of the compound with water, are 1.7 × 10^–6 and 2.7 × 10^–6 g cm^–2 day^–1, respectively, and the degree of leaching is 0.014%. High hydrolytic durability of the compound with respect to uranium leaching reduces the risk of release of uranium isotopes from radioactive waste into the environment.     

Extraction of monocarboxylic acids by trioctylmethylammonium di(2-ethylhexyl)phosphate

The laws of the interphase distribution of saturated monocarboxylic acids in the system with the binary extracanttrioctylmethylammonium di(2-ethylhexyl)phosphate were studied. The extraction isoherms of monocarboxylic acids by 0.2 M solution of trioctylmethylammonium di(2-ethylhexyl)phosphate in toluene were obtained, and it was shown that they are rectilinear. The extractibility of acids decreases in the following order: butyric > propionic > formic> acetic> lactic, which corresponds to the anion-exchange order for the initial salts of quaternary ammonium bases. The mechanisms of the distribution of monocarboxylic acids were proposed. The study of the extraction of acetic and propionic acids as a function of the acidity of the aqueous phase revealed that the acids are extracted most efficiently from acid solutions. A decrease in the distribution coefficients with an increasing pH of the aqueous phase is observed, which indicates the possibility of efficient reextraction of monocarboxylic acids from organic solutions.     

A Study of the Radiolysis Products of the Tri-n-Butyl-Phosphate–Isopar-M–HNO3 System before and after Regeneration with Carbonates of Organic Bases

Protection of Metals and Physical Chemistry of Surfaces - By measuring the hydrodynamic characteristics (viscosity, density of extraction mixture, and interfacial tension) and determining the...     

Thermal Stability of KU-2*8 Sulfocation Exchanger in Contact with Nitric Acid under Isochoric Conditions

Protection of Metals and Physical Chemistry of Surfaces - The thermal stability of KU-2*8 cation exchanger mixed with 4 and 12 mol/L nitric acids is studied via differential scanning calorimetry...     

Production of isobutylene from acetone over micro–mesoporous catalysts

The production of isobutylene from acetone over micro–mesoporous catalysts with different mesopore contents, which have been prepared using hydrothermal recrystallization of mordenite (MOR) zeolite modified with cesium acetate by incipient wetness impregnation, has been studied. It has been shown that cesium is inserted into the cation positions during the modification, at the same time the number of Brønsted acid sites in the samples decreased. It has been found that an increase in the content of mesopores in the catalyst leads to an increase in the initial rates of acetone conversion and isobutylene formation as a result of removing diffusion limitations. Brønsted acid sites have been shown to be preferable for the selective production of isobutylene from acetone. Micro–mesoporous materials operate more stably as compared to microporous materials.