scholarly journals The Effect of Stereochemistry on Sodium Ion Complexation in Nucleoside-Metallacarborane Conjugates

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Agnieszka B. Olejniczak ◽  
Jan Milecki ◽  
Grzegorz Schroeder
Keyword(s):  
Complex Formation ◽  
Alkali Metals ◽  
Equilibrium Constants ◽  
Biological Properties ◽  
Biological Evaluation ◽  
Sodium Ion ◽  
Pyrimidine Nucleosides ◽  
Esi Ms ◽  
Complexing Properties ◽  
Physicochemical And Biological Properties

Conjugates of purine and pyrimidine nucleosides: thymidine and -deoxyguanosine with cobalt-metallacarborane were studied for their sodium ion complexing properties. Formation of stable complexes of 1 : 1 stoichiometry was proved by ESI MS spectroscopy and NMR. Equilibrium constants and energies of complex formation were calculated. Complexation of alkali-metals by nucleoside-metallacarborane conjugates may affect the physicochemical and biological properties of the conjugates and should be taken into consideration during biological evaluation of these types of modifications.

scholarly journals STUDY OF COMPLEX FORMATION OF Co (II) WITH TRIGLYCINE IN AQUEOUS SOLUTION

2020 ◽  
Vol 63 (2) ◽  
pp. 21-25
Author(s):  
Svetlana A. N. Bychkova ◽  
Galina G. N. Gorboletova ◽  
Kseniya O. N. Frolova
Keyword(s):  
Molecular Weight ◽  
Complex Formation ◽  
Potentiometric Titration ◽  
Stability Constants ◽  
Physiological Activity ◽  
Equilibrium Constants ◽  
Equilibrium Concentration ◽  
Low Molecular Weight ◽  
Wide Range ◽  
Complexing Properties

Peptides are an extensive class of both natural and synthetic organic compounds, many of which have high and diverse physiological activity. The relevance of the study of the complexing properties of tripeptides is determined by the large value of these compounds in biological processes, since peptides are a simplified fragment of proteins and are widely used in various sectors of the pharmaceutical industry. One of the representatives of low molecular weight tripeptides is glycyl-glycyl-glycine. In this work, the complex formation of triglycine with Co2+ ions at 298.15 K and I = 0.2 mol/l (KNO3) was studied by potentiometric titration. The study of the complexing properties of triglycine with Co2+ was carried out by the method of potentiometric titration with the ratios M:L = 1:1, 1:2, 1:5. For processing the experimental data, the universal program PHMETR was used, designed to calculate equilibrium constants with an arbitrary number of reactions from the measured equilibrium concentration of one of the particles. The existence of CoL, CoH-1L, CoL2 CoH-2L22–, CoL3–, CoH-3L34– complexes was established. Their stability constants were determined. And the probable structures of the resulting complexes were proposed. The results of this study show that the oxygen and nitrogen atoms of the peptide group are involved in the processes of interaction between Co(II) and triglycine. This significantly changes the thermodynamics of the complex formation of short peptides in comparison with amino acids. The stability constants of cobalt (II) triglycinates obtained in this work allow one to carry out mathematical modeling of equilibria in multicomponent solutions, to predict the behavior of systems in a wide range of concentrations and pH. They can form the basis for generalizations concerning the structure and behavior of low molecular weight peptides in solution, and used for further studies, including calorimetric ones.

Bis(monoazacrown ethers) with an electron-donating substituent at the hinge: A pronounced participation of hydroxyl group in formation of sodium ion sandwich complexes

1989 ◽  
Vol 54 (4) ◽  
pp. 1043-1054 ◽  
Author(s):  
Jiří Závada ◽  
Juraj Koudelka ◽  
Petr Holý ◽  
Martin Bělohradský ◽  
Ivan Stibor
Keyword(s):  
Complex Formation ◽  
Sandwich Structure ◽  
Sodium Ion ◽  
Hydroxyl Group ◽  
Complex Stability ◽  
Sandwich Complexes ◽  
Sandwich Complex ◽  
Marked Enhancement ◽  
Stability Data ◽  
Potentiometric Data

Sodium ion complex formation has been investigated potentiometrically in four homologous bis(crown) series I-IV differing by the nature of substituent placed at the linking trimethylene chain (X = OH, OCH3, OCH2C6H5 and H respectively). A marked enhancement of the complex stability has been observed in the bis(crown) series I and attributed to participation of the lateral hydroxyl group in the sandwich complex formation. Evidence in support of the sandwich structure has been provided (i) by analysis of the potentiometric data indicating a 1:1 complex stoichiometry and (ii) by a comparison of the complex stability data from the bis(crown) series I with the corresponding values from related monocyclic ligand series V, VI and VII revealing a pronounced cooperation of both macrorings in the sodium ion-bis(crown) I complex formation.

scholarly journals The Influence of Bloom Index, Endotoxin Levels and Polyethylene Glycol Succinimidyl Glutarate Crosslinking on the Physicochemical and Biological Properties of Gelatin Biomaterials

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1003
Author(s):  
Zhuning Wu ◽  
Stefanie H. Korntner ◽  
Jos Olijve ◽  
Anne Maria Mullen ◽  
Dimitios I. Zeugolis
Keyword(s):  
Elastic Modulus ◽  
Polyethylene Glycol ◽  
Enzymatic Degradation ◽  
Structural Integrity ◽  
Biological Response ◽  
Biological Properties ◽  
Compression Stress ◽  
Free Amine ◽  
Amine Content ◽  
Physicochemical And Biological Properties

In the medical device sector, bloom index and residual endotoxins should be controlled, as they are crucial regulators of the device’s physicochemical and biological properties. It is also imperative to identify a suitable crosslinking method to increase mechanical integrity, without jeopardising cellular functions of gelatin-based devices. Herein, gelatin preparations with variable bloom index and endotoxin levels were used to fabricate non-crosslinked and polyethylene glycol succinimidyl glutarate crosslinked gelatin scaffolds, the physicochemical and biological properties of which were subsequently assessed. Gelatin preparations with low bloom index resulted in hydrogels with significantly (p < 0.05) lower compression stress, elastic modulus and resistance to enzymatic degradation, and significantly higher (p < 0.05) free amine content than gelatin preparations with high bloom index. Gelatin preparations with high endotoxin levels resulted in films that induced significantly (p < 0.05) higher macrophage clusters than gelatin preparations with low endotoxin level. Our data suggest that the bloom index modulates the physicochemical properties, and the endotoxin content regulates the biological response of gelatin biomaterials. Although polyethylene glycol succinimidyl glutarate crosslinking significantly (p < 0.05) increased compression stress, elastic modulus and resistance to enzymatic degradation, and significantly (p < 0.05) decreased free amine content, at the concentration used, it did not provide sufficient structural integrity to support cell culture. Therefore, the quest for the optimal gelatin crosslinker continues.

Rational Design of Ti-Based Oxygen Redox Layered Oxides for Advanced Sodium-ion Batteries

2021 ◽  
Author(s):  
Jaewoon Lee ◽  
Sojung Koo ◽  
Jinwoo Lee ◽  
Duho Kim
Keyword(s):  
Transition Metals ◽  
Redox Reactions ◽  
Rational Design ◽  
Alkali Metals ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Layered Oxides

Considering Mn4+ (3d3)-based cations, various layered oxides (A[AyM1-y]O2, where A and M refer to alkali metals and transition metals, respectively) exhibiting oxygen-redox reactions have been investigated extensively to achieve high...

The depolymerization of chitosan: effects on physicochemical and biological properties

2004 ◽  
Vol 281 (1-2) ◽  
pp. 45-54 ◽  
Author(s):  
Shirui Mao ◽  
Xintao Shuai ◽  
Florian Unger ◽  
Michael Simon ◽  
Dianzhou Bi ◽  
...  
Keyword(s):  
Biological Properties ◽  
Physicochemical And Biological Properties

Rational design and fabrication of a β-dicalcium silicate-based multifunctional cement with potential for root canal filling treatment

2014 ◽  
Vol 2 (24) ◽  
pp. 3830-3838 ◽  
Author(s):  
Xianyan Yang ◽  
Min Liu ◽  
Yu Zhao ◽  
Hongyu Jia ◽  
Sanzhong Xu ◽  
...  
Keyword(s):  
Root Canal ◽  
Rational Design ◽  
Biological Properties ◽  
Dicalcium Silicate ◽  
Root Canal Therapy ◽  
Root Canal Filling ◽  
Physicochemical And Biological Properties

Gypsum-introduced, CaO-rich dicalcium silicate-based cements exhibit multifunctional physicochemical and biological properties and meet some challenging criteria in root canal therapy.

Sign in / Sign up

Export Citation Format

Share Document