Hominid cranial capacity change through time: a darwinian process

1987 ◽  
Vol 2 (3) ◽  
pp. 213-220 ◽  
Author(s):  
M. Henneberg
2021 ◽  
Vol 22 (14) ◽  
pp. 7365
Author(s):  
Piotr Cysewski ◽  
Maciej Przybyłek ◽  
Anna Kowalska ◽  
Natalia Tymorek

In this study, the temperature-dependent solubility of nicotinamide (niacin) was measured in six neat solvents and five aqueous-organic binary mixtures (methanol, 1,4-dioxane, acetonitrile, DMSO and DMF). It was discovered that the selected set of organic solvents offer all sorts of solvent effects, including co-solvent, synergistic, and anti-solvent features, enabling flexible tuning of niacin solubility. In addition, differential scanning calorimetry was used to characterize the fusion thermodynamics of nicotinamide. In particular, the heat capacity change upon melting was measured. The experimental data were interpreted by means of COSMO-RS-DARE (conductor-like screening model for realistic solvation–dimerization, aggregation, and reaction extension) for concentration dependent reactions. The solute–solute and solute–solvent intermolecular interactions were found to be significant in all of the studied systems, which was proven by the computed mutual affinity of the components at the saturated conditions. The values of the Gibbs free energies of pair formation were derived at an advanced level of theory (MP2), including corrections for electron correlation and zero point vibrational energy (ZPE). In all of the studied systems the self-association of nicotinamide was found to be a predominant intermolecular complex, irrespective of the temperature and composition of the binary system. The application of the COSMO-RS-DARE approach led to a perfect match between the computed and measured solubility data, by optimizing the parameter of intermolecular interactions.


1999 ◽  
Vol 8 (7) ◽  
pp. 1500-1504 ◽  
Author(s):  
C. Nick Pace ◽  
Gerald R. Grimsley ◽  
Susan T. Thomas ◽  
George I. Makhatadze

Nature ◽  
1983 ◽  
Vol 305 (5934) ◽  
pp. 525-527 ◽  
Author(s):  
Alan Walker ◽  
Dean Falk ◽  
Richard Smith ◽  
Martin Pickford
Keyword(s):  

2016 ◽  
Vol 23 (5) ◽  
pp. 72-82
Author(s):  
Dennis Erhisenebe Eboh ◽  
◽  
Ewaen Churchill Okoro ◽  
Kingsley Afoke Iteire ◽  
◽  
...  

2010 ◽  
Vol 375 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Ken-ichi Amano ◽  
Daisuke Miyazaki ◽  
Liew Fong Fong ◽  
Paul Hilscher ◽  
Taro Sonobe

2020 ◽  
Author(s):  
Zhengrong Yang ◽  
Donald D. Muccio ◽  
Nathalia Melo ◽  
Venkatram R. Atigadda ◽  
Matthew B. Renfrow

ABSTRACTDifferential scanning calorimetry and differential scanning fluorimetry were used to measure the thermal stability of human retinoid X receptor-alpha ligand binding domain (RXRα LBD) homodimer in the absence or presence of rexinoid and coactivator peptide, GRIP-1. The apo-RXRα LBD homodimer displayed a single thermal unfolding transition with a Tm of 58.7 °C and an unfolding enthalpy (ΔH) of 673 kJ/mol (12.5 J/g), much lower than average value (35 J/g) of small globular proteins. Using a heat capacity change (ΔCp) of 15 kJ/(mol·K) determined by measurements at different pH values, the free energy of unfolding (ΔG) of the native state was 33 kJ/mol at 37 °C. Rexinoid binding to the apo-homodimer increased Tm by 5 to 9 °C, and increased the ΔG of the native homodimer by 12 to 20 kJ/mol at 37 °C, consistent with the nanomolar dissociation constant (Kd) of the rexinoids. The increase in ΔG was the result of a more favorable entropic change due to interactions between the rexinoid and hydrophobic residues in the binding pocket, with the larger increases caused by rexinoids containing larger hydrophobic end groups. GRIP-1 binding to holo-homodimers containing rexinoid resulted in additional increases in ΔG of 14 kJ/mol, a value same for all three rexinoids. Binding of rexinoid and GRIP-1 resulted in a combined 50% increase in unfolding enthalpy, consistent with reduced structural fluidity and more compact folding observed in other published structural studies. Thermodynamic analysis thus provided a quantitative evaluation of the interactions between RXR and its agonist and coactivator.


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