Search

Your search keyword '"Konstantinova, M."' showing total 291 results
Start Over Author "Konstantinova, M." Language english
291 results on '"Konstantinova, M."'

17. X-Linked Recessive Form of Nephrogenic Diabetes Insipidus in A 7-Year-Old Boy

Author

Janchevska A., Tasic V., Gucev Z., Krstevska-Konstantinova M., and Cheong H. I.

Subjects
nephrogenic diabetes insipidus (ndi), arginine vasopressin (avp), antidiuretic hormone (adh), urine osmolality, Genetics, QH426-470
Abstract

Nephrogenic diabetes insipidus (NDI) is caused by the inability of renal collecting duct cells to respond to arginine vasopressin (AVP)/antidiuretic hormone (ADH). We present the case of a 7-year-old boy with a history of excretion of large amounts of dilute urine and polydipsia since infancy. The boy had several vomiting episodes with mild dehydration during the first 3 years of life. There was no evidence of headaches, dizziness or visual problems. He drinks between 2 and 3 L/day and has 24-hour diuresis of 2 liters, now. He has prepubertal appearance with appropriate weight [+0.85 standard deviation score (SDS)] and height (+0.15 SDS) for his age. His intelligence was also normal. The water deprivation test showed low urine osmolality after 8 hours of dehydration. After desmopressin administration, urine osmolality remained low. Serum osmolality was in the normal range for sex and age before and after desmopressin administration. This indicated a nephrogenic form of diabetes insipidus. Molecular analyses revealed a P286L [p.Pro(CCC)286Leu(CTC)] mutation in the AVPR2 gene, that was inherited from his mother. This patient is the first case with genetically confirmed X-linked inherited form of NDI in the Republic of Macedonia. Molecular analysis confirmed the clinical diagnosis and enabled genetic advice for this family.

Published
2014
Full Text
View/download PDF

37. The role of Zn in the sustainable one-pot synthesis of dimethyl carbonate from carbon dioxide, methanol and propylene oxide

Author

Liu, M., Konstantinova, M., Negahdar, L., and McGregor, J.

Abstract

Dimethyl carbonate (DMC) can be applied as a greener alternative to more hazardous materials, e.g. phosgene or dimethyl sulfate. Herein, one-pot synthesis of DMC from propylene oxide, methanol and CO2 using alkali halide catalysts under mild conditions was studied. Addition of Zn powder to the K2CO3-NaBr-ZnO catalyst system was seen to increase DMC selectivity from 19.8% (TOF = 39.0 h-1) to 40.2% (TOF = 78.1 h-1) at 20 bar and 160 °C for 5 h. Catalyst characterisation showed that Zn powder increases the stability of the catalyst, preventing the active ingredients on the catalyst surface from leaching. An increase in propylene oxide conversion to DMC is attributed to the increase of Zn2+ ions in the reaction solution. Elevated pressure was not found to be a necessary reaction condition for transesterification. This study shows that increased selectivity to DMC can be achieved at mild conditions with the addition of Zn powder.

Published
2021

44. Dispersion characteristics of complex electromechanical parameters of porous piezoceramics.

Author

Shvetsov, I. A., Lugovaya, M. A., Konstantinova, M. G., Abramov, P. A., Petrova, E. I., Shvetsova, N. A., and Rybyanets, A. N.

Subjects
PIEZOELECTRIC ceramics, DISPERSION (Chemistry), CERAMICS
Abstract

In this paper, the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically "hard" porous piezoceramics based on PZT composition were presented. Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former. The complex constants of porous piezoceramics with relative porosity 16% and their frequency dependences were measured using the piezoelectric resonance analysis method. As a result of experimental studies, regions of elastic, piezoelectric and electromechanical dispersion, characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found. It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics. In conclusion, the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

49. 137Cs AND 239,240Pu ACTIVITY CONCENTRATIONS DISTRIBUTION IN WATERLOGGED AND NON-BOGGY SOILS OF LITHUANIA.

Author

Kazakevičiūtė-Jakučiūnienė, L., Tarasiuk, N., Maceika, E., Druteikienė, R., Konstantinova, M., Žukauskaitė, Z., Gvozdaitė, R., and Buivydas, Š.

Subjects
WATERLOGGING (Soils), NUCLEAR weapons testing, CLAY soils, CESIUM, RADIOISOTOPES, SOIL composition, PLUTONIUM
Abstract

Copyright of Lithuanian Journal of Physics is the property of Lithuanian Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results