Thermodynamic properties of metal amides determined by ammonia pressure-composition isotherms

Hino, Satoshi; Ichikawa, Takayuki; Kojima, Yoshitsugu

doi:10.1016/j.jct.2009.07.024

Cited by 25 publications

(17 citation statements)

References 16 publications

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“…Fig. 1 shows the XRD patterns collected on 2NaNH 2 -3MgH 2 (sm) and samples milled for 1, 3, 6, 9 and 18 h. Besides the Bragg reflections corresponding to the starting materials, the pattern of 2NaNH 2 -3MgH 2 (1 h) sample shows the presence of NaH and a new set of reflections at 2Â = 34.7 • , 40.8 • and 59.3 • , which are consistent with those assigned to MgNH [25,26]. With increase in the milling time to 3 h the contribution from the starting materials diminishes whereas the Bragg reflections corresponding to NaH and MgNH become more pronounced.…”

Section: Resultssupporting

confidence: 69%

Mechanochemical transformations in NaNH2-MgH2 mixtures

Singh

Kobayashi

Dolotko

et al. 2012

Journal of Alloys and Compounds

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Section: Resultssupporting

confidence: 69%

Mechanochemical transformations in NaNH2-MgH2 mixtures

Singh

Kobayashi

Dolotko

et al. 2012

Journal of Alloys and Compounds

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“…Hence, the latter effect might be mitigated considering smaller surfaces for protein Γ. Analysing the behaviour of the binding process as a function of temperature we find that the random binding is overall very strong and it decreases while increasing the temperature. The van't Hoff plot 63,64 shows positive binding affinities and an exothermic process above the folding temperature (Fig. S7 SM; about the evaluation of the association constant and Fig.…”

Section: Resultsmentioning

confidence: 99%

Protein design under competing conditions for the availability of amino acids

Nerattini¹,

Tubiana²,

Cardelli³

et al. 2020

Sci Rep

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isolating the properties of proteins that allow them to convert sequence into the structure is a longlasting biophysical problem. In particular, studies focused extensively on the effect of a reduced alphabet size on the folding properties. However, the natural alphabet is a compromise between versatility and optimisation of the available resources. Here, for the first time, we include the impact of the relative availability of the amino acids to extract from the 20 letters the core necessary for protein stability. We present a computational protein design scheme that involves the competition for resources between a protein and a potential interaction partner that, additionally, gives us the chance to investigate the effect of the reduced alphabet on protein-protein interactions. We devise a scheme that automatically identifies the optimal reduced set of letters for the design of the protein, and we observe that even alphabets reduced down to 4 letters allow for single protein folding. However, it is only with 6 letters that we achieve optimal folding, thus recovering experimental observations. Additionally, we notice that the binding between the protein and a potential interaction partner could not be avoided with the investigated reduced alphabets. therefore, we suggest that aggregation could have been a driving force in the evolution of the large protein alphabet. The amino acid alphabet encoding the protein function is common to all living organisms and is the result of millions of years of evolution. It is composed of 20 letters, in contrast to the ones of other biopolymers, such as DNA and RNA, which possess 4 letters only. Such a large alphabet gives to proteins the vast variety of configurations and functions that we know so far. The advent of computational protein evolution (also known as protein design) 1-16 opens the possibility to address fundamental questions about the nature of the amino acid alphabet 17-20. Protein design consists in searching for protein sequences capable of folding into a given backbone conformation. The search is usually done by point mutations while keeping the backbone structure fixed. In addition to several applications to medicine 12,14,21-23 and material science 15,24-27 , protein design offers the possibility to explore fundamental problems of protein evolution. One of the questions that mostly attracts the attention of the scientific community is about the universality of the 20 letters. Of course, the complex spectrum of proteins functionalities calls for a wide range of building blocks. However, could it be possible to design proteins to fold using a reduced alphabet? And, if yes, why not simply stick with such a reduced alphabet? The early work on protein design with alphabets of different sizes was carried out for protein lattice models in which the protein chain is constrained to be on a cubic lattice. With such models it was possible to design heteropolymers with a large variety of alphabets defined by the amino acid interactions 28-37. It became rapidly apparent th...

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“…The thermodynamic studies were carried out at 303, 313, and 323 K. Usually a very high temperature is not reliable for adsorption studies because of the possibility of damaging of active sites of the adsorbent . The thermodynamic parameters, ΔG , ΔH , and ΔS were evaluated using Equation and Equation :

Δ G = Δ H - T Δ S

\log ((), \frac{q_{e}}{C_{e}}) = \frac{Δ S}{2.303 R} - \frac{Δ H}{2.303 italicRT}

…”

Section: Resultsmentioning

confidence: 99%

Synthesis of MoO₃/polypyrrole nanocomposite and its adsorptive properties toward cadmium(II) and nile blue from aqueous solution: Equilibrium isotherm and kinetics modeling

Siddiqui

Khan²,

Khan

2019

Env Prog and Sustain Energy

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Molybdenum trioxide/polypyrrole (MoO3/Ppy) nanocomposite was prepared via oxidative polymerization of pyrrole monomer with MoO3 nanoparticles. The adsorption of Cd+2 and nile blue (NB) onto the nanocomposite was investigated in terms of various process parameters. The characterization of MoO3/Ppy nanocomposite was carried out by Fourier transform‐infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive X‐ray spectroscopy. Higher R2 (0.992–0.997 for Cd+2 and 0.997–0.998 for NB) and lower standard error of estimation values (1.04–1.82 for Cd+2 and 0.87–1.07 for NB) for Freundlich isotherm highlighted the multilayer adsorption onto heterogeneous nanocomposite surface. The higher Qm values at 323 K for Cd+2 (181 mg/g) and NB (189 mg/g) compared to many reported adsorbents proved the adsorptive superiority of MoO3/Ppy. The energy of adsorption (E) values from Dubinin–Radushkevich model was 1.26–1.38 and 1.36–1.44 kJ/mol for Cd+2 and NB, respectively, suggesting physical adsorption. Pseudo‐second order kinetic model governed the adsorption of Cd+2 and NB with intraparticle and liquid film diffusion controlling the mechanism. The negative ΔG values (8.4–9.4 kJ/mol) and positive ΔH values (2.5–6.1 kJ/mol) implied spontaneous and endothermic adsorption process. The positive ΔS values (0.036–0.048 kJ/mol/K) indicated increased randomness at MoO3/Ppy‐Cd+2 or NB interface. The MoO3/Ppy nanocomposite proved to be suitable and efficient adsorbent for sequestering of Cd+2 and NB from aqueous solution.

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Thermodynamic properties of metal amides determined by ammonia pressure-composition isotherms

Cited by 25 publications

References 16 publications

Mechanochemical transformations in NaNH2-MgH2 mixtures

Mechanochemical transformations in NaNH2-MgH2 mixtures

Protein design under competing conditions for the availability of amino acids

Synthesis of MoO₃/polypyrrole nanocomposite and its adsorptive properties toward cadmium(II) and nile blue from aqueous solution: Equilibrium isotherm and kinetics modeling

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Thermodynamic properties of metal amides determined by ammonia pressure-composition isotherms

Cited by 25 publications

References 16 publications

Mechanochemical transformations in NaNH2-MgH2 mixtures

Mechanochemical transformations in NaNH2-MgH2 mixtures

Protein design under competing conditions for the availability of amino acids

Synthesis of MoO3/polypyrrole nanocomposite and its adsorptive properties toward cadmium(II) and nile blue from aqueous solution: Equilibrium isotherm and kinetics modeling

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Product

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Synthesis of MoO₃/polypyrrole nanocomposite and its adsorptive properties toward cadmium(II) and nile blue from aqueous solution: Equilibrium isotherm and kinetics modeling