Search

Oral semaglutide is the first oral glucagon-like peptide-1 (GLP-1) receptor agonist for glycaemic control in patients with type 2 diabetes. Type 2 diabetes is commonly associated with renal impairment, restricting treatment options. We aimed to investigate the efficacy and safety of oral semaglutide in patients with type 2 diabetes and moderate renal impairment.

This review covers the works on the sol-gel preparation of oxides from metal alkoxides that were carried out at the Faculty of Chemistry, Moscow State University, and at the Karpov Research Institute of Physical Chemistry. The composition and properties of the oxide powders and films prepared were considered in relation to the nature of alkoxides and solvents and complex formation in solution. The morphology and phase composition of the powders were examined in relation to hydrolysis conditions. Electrical and optical data are presented for titanate, zirconate, niobate, and tantalate powders, ceramics, and films

Crystalline LiNbO3 was prepared by simultaneous hydrolysis of lithium and niobium alkoxides (in the mole ratio Li : Nb = 1 :1) followed by heat treatment. Crystallization of LiNbO3 occurs in a wide temperature region, 350 to 700° C, directly from an amorphous hydrolysis product containing residual alkoxy and hydroxy groups. Heat treatment at 700° C results in the formation of fully crystalline LiNbO3 powder with completely formed ferroelectric properties. Hydrolysis of metal alkoxide solutions is successfully used to obtain high-quality LiNbO3 crystalline thin films.

Preparation of the metal alkoxide solutions-precursors for powders and thin films of the supercon ductor YBa2Cu3O7-x is discussed. Films, powders and ceramics of the superconductor YBa2Cu3O7-x have been obtained. Oriented and polycrystalline films with the thickness of 0.1-0.15μm and different morphology have been studied. Resistivity of the films turned to zero at 70-77K.

X-ray structural analysis of “crystalline alkoxides” in many cases reveals that along with OR-groups their molecules also contain oxo-ligands. The following possible reactions leading to formation of oxoalkoxides have been discussed: hydrolysis, pyrolysis (frequently uncontrollable), ether elimination, oxidation of OR-groups (which exist in solutions of alkali, alkaline-earth and rare earth elements), or alkoxides of the lower oxidation states (which are formed by reduction of M(OR)n on cathode during electrolysis or by hydrogen in statu nascendi). Oligomeric oxoalkoxides differ from the polymeric alkoxides M(OR)n in considerably higher solubility and reactivity. The most important role of oxoalkoxides in the processes of formation of oxides has been demonstrated using as an example preparation of BaTiO3 from alkoxides.

Fine powders of ZrO2, ZrO2-Y2O3, BaTi1-xZrxO3 have been obtained by hydrolysis of alkoxides. For preparation of ZrO2-based materials precipitation from the partially hydrolyzed alkoxides solutions (sols) has been used. Barium titanate-based materials were obtained by hydroxide-alkoxide route with quick hydrolysis of titanium butoxide by excess of water on the first stage. The effect of the hydrolysis conditions on the size, shape, and specific surface area of the oxide powders has been discussed. Some considerations on comparison of the two hydrolytic techniques have been suggested.

It is presented a brief overview of our results in the field of harnessing sol-gel techniques for promoting thin films in microelectronics technology. We discuss the problem of multilevel interconnection of IC, preparation of ferroelectric films, taper etching of oxide films, formation of isolating and passivating coatings on compound semiconductors, production of barrier zirconia and titania films, as well as certain aspects of practical use of the method in microelectronics.

Without Abstract:

Electrochemically prepared methoxyethoxide solutions have been suggested as precursors for sol-gel technology. Methoxyethoxides demonstrate higher stability in organic solvents than alkoxides; chelating properties of the ether oxygen cause considerable stability of methoxyethoxides to hydrolysis in comparison with the derivatives of aliphatic alcohols. This makes methoxyethoxides promising precursors for oxide synthesis. Methoxyethanol proved an exceptionally convenient solvent for electrochemical synthesis. The electrochemically prepared solutions demonstrate unique film-forming properties and were used for synthesis of the films of complex perovskites BaM111/3Mv2/3O3 (M11 = Zn, Co, Ni; Mv = Nb, Ta), yttrium-stabilized ZrO2, PZT.

Polycrystalline Pb(Zr0.48Ti0.52)O3 thin films with the thickness of 0.2 μm on Pt-coated silicon substrates have been prepared by sol-gel process using electrochemically prepared titanium and zirconium solutions in methoxyethanol. Structure, morphology, and electrical properties of the films annealed by usual isothermal annealing for 1 hour and by rapid thermal annealing (RTA) for 1 minute have been studied. In contrast to isothermal annealing RTA results in highly oriented (100) films. This leads to higher dielectric constant (more than twice) of RTA annealed films, but no correlation between degree of orientation and polarization have been observed. Special attention has been paid to capacitance-voltage (CV) characteristics. Some parameters and simple models were introduced for the interpretation of CV data. Thus asymmetry of CV curves indicates that for the films prepared by RTA there exists a problem of disturbed layer formation at the Pt-PZT interface.

The kinetics of grain growth in compacts made of submicron titanium powders obtained by controlled hydrolysis of titanium alcoholates was studied. It was established that inhomogeneous packing of the particles in a compact made of agglomerated powder stimulates intense grain growth even in the early stage of sintering. It is shown that a material obtained by sintering homogeneously packed compacts composed of coarse non-agglomerated particles possesses, despite a low density, a homogeneous highly disperse structure and exhibits a much higher strength than a material obtained upon sintering a finely divided but agglomerated powder to maximum density.

Powders and thin films of the following simple and complex oxides have been obtained from metal alkoxides: MIITiO3 (M= Mg, Ca-Ba), MM1/3B2/3O3 (M= Sr, Ba, M' = Mg-Zn; B= Nb, Ta); MNbO3(M= Li, Na); ZrTiO4; PbTiO3; PZT, PLZT-materials; M2BO4 (M= Li, Na; B= Mo, W), Bi2BO6(B= Mo, W); LixWO3, WO3, MoO3, Bi2O3-WO3(solid solutions), YFeO3, Y3Fe5O12; YBa2Cu3O7-; Bi2Sr2CaCu2Ox; Bi2Sr2Ca2Cu3Ox. For synthesis of metal alkoxides and solutions containing two or more elements electrochemical technique (the anodic dissolution of metals in alcohols) has been used. Analysis of different examples emphasises that considerable attention in sol-gel chemistry of oxides should be paid to decomposition of M(OR)n with elimination of ether and formation of oxoalkoxides, containing M-O-M' bonds-the basis of future oxide phases.

Different ways of dehydration of lead acetate trihydrate for its application in sol-gel techniques are discussed. Reaction of Pb(CH3COO)2·3H2O with acetic acid anhydride proved to be the most efficient way of its dehydration. Characteristics of the solutions of lead acetate in methoxyethanol dehydrated by different methods are presented. Solutions for preparation of PZT films are prepared using electrochemical dissolution of titanium and zirconium in methoxyethanol. Physico-chemical properties of these solutions alongside with structural and electrical characteristics of the PZT films obtained from these solutions are presented. The effect of lead content in solutions on the properties of the films obtained is discussed.

We have given some results above of laboratory and field research on the structures and mechanical and physical-chemical properties of coals from burst-prone and burst-free seams, as well as results of studies of the movement of gas in coal seams, carried out at the Skochinskii Mining Institute over the last 15 years.

Summary:

The reaction between titanium and zirconium isopropoxides in isopropanol, occasionally in the presence of barium isopropoxide, was studied at different temperatures. No complexation between the titanium and zirconium alkoxides was detected. A concentration region was revealed in which the three alkoxides coexist in solution. Crystalline, fine-particle BaZr0.1Ti0.9O3powder was prepared at 80°C by the alkoxide method. Its morphology was compared with that of a powder of identical composition prepared by the alkoxide–hydroxide method.

Abstract: Sintering of monodisperse titania powders with a relatively large grain size (0.84±0.24 µm) is investigated. It is established that the use of nonagglomerated monodisperse powders makes it possible to fabricate ceramics with a density of 99.5% of the theoretical value and a narrow distribution of pore sizes without preliminary milling and by relatively simple technological means, namely, cold pressing and casting into gypsum molds followed by sintering at a relatively low temperature. In combination with a high density such a structure makes the developed ceramic material applicable for the production of porous membranes for microbiology and medicine.

Aim: To study the access to dental care in schoolchildren from families with low socio- economic status (SES) comparing to children from families with non-low SES.Methods: The study was approved by the Regional Ethics Committee. Informed consent from the parents of children was obtained. Per capita family income less than the minimum subsistence level in the region was defined as low SES. In 2012 in 10 out of 30 Volzhskiy schools all schoolchildren from the families with low SES (430 children aged 7-17 years, LS group) were identified according to the list of the Educational Department. In the same schools 418 schoolchildren were randomly selected from the families with non-low SES (NLS control group). The groups were identical by sex and age of the children. The children were examined by an experienced dentist. The number (mean ± standard error) of untreated decayed permanent teeth was calculated. The parents and the children were interviewed on the child access to dental care. The differences were assessed with Student’s t-test.Results: The mean number of untreated decayed teeth in the LS group was significantly (p<0.001) higher than in NLS group: in 7-8-year-olds 1.7±0.1 vs 0.7±0.2; in 9-11-year- olds 2.0±0.2 vs 0.8±0.1; in 12-14-year-olds 3.1±0.2 vs 1.1±0.1; in 15-17 year-olds 4.0±0.2 vs 1.2±0.2. The children from LS group visited a dentist during the last 6 months less often than the children from NLS group: 172 of 430 (40.0%) vs 326 of 418 (78.0%) respectively, p<0.001. The number of children who had visited a dentist 1-2 years before or did not remember when they had visited a dentist in LS group was higher than in the NLS group: 181 of 430 (42.1%) vs 34 of 418 (8.1%) answers, p<0.001.Conclusions: This sample of Volzhskiy schoolchildren from LS families reported more limited access to dental care than the schoolchildren from NLS families, and they had higher numbers of untreated permanent teeth.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hydrolysis of a mixture of Bi(OEt)3and WO(OEt)4in an ethanolic solution affords directly crystalline complex oxide phases (containing up to 35 mol% of WO3).