Search results

1

Elements of thermodynamics in RNA evolution.

100%

Kierzek E., Biała E., Kierzek R.

Acta Biochimica Polonica

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2001

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vol. 48

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issue 2

485-493

EN

The paper presents some aspects correlating thermal stability of RNA folding and the occurrence of structural motifs in natural ribonucleic acids. Particularly, the thermodynamic stability of 2'-5' and 3'-5' linked RNA and the contribution of unpaired terminal nucleotides (dangling ends) in secondary (2D) and tertiary (3D) structures of RNA are discussed. Both examples suggest that during evolution nature selected sequences and structures of RNA which are the most thermally stable and efficient for their biological function.

2

Thermodynamics of a 3 - D charged rotating hairy black hole

100%

Naji J., Heydari S., Amjadi A.

Open Physics

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2014

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vol. 12

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issue 9

687-692

EN

In this paper, we consider a charged rotating black hole in three dimensions with a scalar charge, and discuss thermodynamics quantities. We find effects of the black hole parameters on the temperature, entropy, free energy, total energy and specific heat. We also investigate the stability of the black hole and study phase transition. We consider the first law of thermodynamics and find that satisfied.

3

Planck-scale corrections to Friedmann equation

80%

Awad A., Ali A.

Open Physics

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2014

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vol. 12

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issue 4

245-255

EN

Recently, Verlinde proposed that gravity is an emergent phenomenon which originates from an entropic force. In this work, we extend Verlinde’s proposal to accommodate generalized uncertainty principles (GUP), which are suggested by some approaches to quantum gravity such as string theory, black hole physics and doubly special relativity (DSR). Using Verlinde’s proposal and two known models of GUPs, we obtain modifications to Newton’s law of gravitation as well as the Friedmann equation. Our modification to the Friedmann equation includes higher powers of the Hubble parameter which is used to obtain a corresponding Raychaudhuri equation. Solving this equation, we obtain a leading Planck-scale correction to Friedmann-Robertson-Walker (FRW) solutions for the p = ωp equation of state.

4

Hydrodynamic cavitation: from theory towards a new experimental approach

80%

Lucia U., Gervino G.

Open Physics

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2009

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vol. 7

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issue 3

638-644

EN

Hydrodynamic cavitation is analysed by a global thermodynamics principle following an approach based on the maximum irreversible entropy variation that has already given promising results for open systems and has been successfully applied in specific engineering problems. In this paper we present a new phenomenological method to evaluate the conditions inducing cavitation. We think this method could be useful in the design of turbo-machineries and related technologies: it represents both an original physical approach to cavitation and an economical saving in planning because the theoretical analysis could allow engineers to reduce the experimental tests and the costs of the design process.

5

On the thermodynamics of phase transitions in metal hydrides

80%

Vita A.

Open Physics

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2012

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vol. 10

|

issue 1

86-95

EN

Metal hydrides are solutions of hydrogen in a metal, where phase transitions may occur depending on temperature, pressure etc. We apply Le Chatelier’s principle of thermodynamics to a particular phase transition in TiHx, which can approximately be described as a second-order phase transition. We show that the fluctuations of the order parameter correspond to fluctuations both of the density of H+ ions and of the distance between adjacent H+ ions. Moreover, as the system approaches the transition and the correlation radius increases, we show -with the help of statistical mechanics-that the statistical weight of modes involving a large number of H+ ions (‘collective modes’) increases sharply, in spite of the fact that the Boltzmann factor of each collective mode is exponentially small. As a result, the interaction of the H+ ions with collective modes makes a tiny suprathermal fraction of the H+ population appear. Our results hold for similar transitions in metal deuterides, too. A violation of an -insofar undisputed-upper bound on hydrogen loading follows.

6

An approach to modeling and thermodynamic analysis of modern power engineering systems

70%

Kozaczka J., Kolat P.

Chemical and Process Engineering

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2011

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vol. 32

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issue 4

401-410

EN

The new efficient method of modeling and thermodynamic analysis of power engineering systems has been presented. With its help a comparison of different structures and investigation of the influence of a particular constituent process onto the whole system efficiency is possible. The shaft work or the exergy is the main thermodynamic quantity taken into account in analyses, and the appropriate dimensionless modeling parameter has been introduced.

7

Hard-thermal-loop QCD trace anomaly

70%

Su N.

Open Physics

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2012

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vol. 10

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issue 6

1379-1381

EN

In this proceedings I summarize results of QCD trace anomaly from recent three-loop hard-thermal-loop perturbation theory (HTLpt) calculations. I focus on the trace anomaly scaled by T 2 for pure-glue and N f = 3 QCD. The comparison to available lattice data suggests that for pure-glue QCD agreement between HTLpt results and lattice data for the trace anomaly begins at temperatures above 8 T c while when including quarks (N f = 3) agreement begins already at temperatures above 2 T c. The results in both cases indicate that at very high temperatures the T 2-scaled trace anomaly increases with temperature in accordance with the predictions of HTLpt.

8

Interaction of anesthetic supplement thiopental with human serum albumin

70%

Khan S., Islam B., Rajeswari M., Usmani, H., Khan A.

Acta Biochimica Polonica

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2008

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vol. 55

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issue 2

399-409

EN

Thiopental (TPL) is a commonly used barbiturate anesthetic. Its binding with human serum albumin (HSA) was studied to explore the anesthetic-induced protein dysfunction. The basic binding interaction was studied by UV-absorption and fluorescence spectroscopy. An increase in the binding affinity (K) and in the number of binding sites (n) with the increasing albumin concentration was observed. The interaction was conformation-dependent and the highest for the F isomer of HSA, which implicates its slow elimination. The mode of binding was characterized using various thermodynamic parameters. Domain II of HSA was found to possess a high affinity binding site for TPL. The effect of micro-metal ions on the binding affinity was also investigated. The molecular distance, r, between donor (HSA) and acceptor (TPL) was estimated by fluorescence resonance energy transfer (FRET). Correlation between the stability of the TPL-N and TPL-F complexes and drug distribution is discussed. The structural changes in the protein investigated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy reflect perturbation of the albumin molecule and provide an explanation for the heterogeneity of action of this anesthetic.

9

Phonon-Induced Thermodynamic Properties of Ultra-narrow Wires

70%

Ilić D., Šetrajčić J., Jaćimovski S.

Acta Physica Polonica A

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2018

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vol. 133

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issue 1

57-62

EN

In this paper, we investigated the influence of size effect on thermodynamic properties of ultra-narrow wires with a simple cubic lattice, by means of two-time dependent Green functions method, adjusted to confined crystalline structures. Poles of Green functions, which defining phonon spectra, are found by solving the secular equation. For different boundary parameters, this problem is presented graphically. The temperature behavior of ultra-narrow wire thermal capacitance is compared to that of bulk structures. It turned out that in low-temperature region thermal capacitance of the ultra-narrow wire is notably lower than in the corresponding bulk sample. How this fact reflects the thermal, conducting and superconducting properties of materials, is discussed in the conclusion.

10

Free energy of helix propagation in short polyalanine chains determined from peptide growth simulations of La3+-binding model peptides. Comparison with experimental data

70%

Maciejczyk M., Hermans J., Bierzyński A.

Acta Biochimica Polonica

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2006

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vol. 53

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issue 1

121-130

EN

Molecular dynamics (MD) is, at present, a unique tool making it possible to study, at the atomic level, conformational transitions in peptides and proteins. Nevertheless, because MD calculations are always based on a more or less approximate physical model, using a set of approximate parameters, their reliability must be tested by comparison with experimental data. Unfortunately, it is very difficult to find a peptide system in which conformational transitions can be studied both experimentally and using MD simulations so that a direct comparison of the results obtained in both ways could be made. Such a system, containing a rigid α-helix nucleus stabilized by La3+ coordination to a 12-residue sequence taken from an EF-hand protein has recently been used to determine experimentally the helix propagation parameters in very short polyalanine segments (Goch et al. (2003) Biochemistry 42: 6840-6847). The same parameters were calculated here for the same peptide system using the peptide growth simulation method with, alternatively, charmm 22 and cedar potential energy functions. The calculated free energies of the helix-coil transition are about two times too large for cedar and even three times too large for charmm 22, as compared with the experimental values. We suggest that these discrepancies have their origin in the incorrect representation of unfolded peptide backbone in solution by the molecular mechanics force fields.

11

Excess thermodynamic quantities of D2O water calculated from its Raman O−D stretching spectra

61%

Georgiev M., Goutev N., Nickolov Z., Georgiev G.

Open Physics

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2005

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vol. 3

|

issue 1

104-114

EN

Excess thermodynamic functions of D2O water have been calculated from the vibrationally decoupled O−D stretching spectra of very dilute solutions of HOD in H2O. Comparison of the results with reference calorimetric data for water showed a good correspondence for excess heat capacity above the melting point of ice. The excess enthalpy at the melting point also coincides well with latent heat of melting.

12

The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent

61%

Tejada-Tovar C., Villabona-Ortíz Á., Gonzalez-Delgado A. D., Tejada-Tovar C., Villabona-Ortíz Á., Gonzalez-Delgado A. D.

Journal of Water and Land Development

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2021

|

issue 48

13

A quantum version of the classical Szilard engine

61%

Bracken P.

Open Physics

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2014

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vol. 12

|

issue 1

1-8

EN

A reinvention of the classical Maxwel demon was proposed by Szilard around the time quantum mechanics was developed. His model continues to attract great interest, especially quantum versions of it. A quantum formulation of the Szilard engine is introduced and investigated here. It is made to operate through specified cycles in such a way that all thermodynamic quantities which pertain to the system can be evaluated exactly in closed form along each sequence of steps through a cycle. It is shown that as a result of the structure of the model, it is possible to calculate and compare various thermodynamic quantities as the engine proceeds around a well defined specific cycle.

14

Batch Adsorption Studies on Rice Husk with Methyl Violet Dye

61%

Omokpariola D. O., Otuosorochi J. N.

World News of Natural Sciences

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2020

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vol. 33

48-63

EN

The potential of rice husks powder (RHP) for the removal of methyl violet dye from aqueous solution was investigated. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dye adsorption process. The optimum conditions for the adsorption of MV onto the adsorbent (RHP) was found to be: contact time (100 min) pH (10.0) and temperature (303 K) for an initial dye concentration of 50 mg/l and adsorbent dose of 1.0 g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich Isotherm model for both dyes adsorption. The maximum adsorption capacity was found to be 1.66 mg/g for the adsorption of MV dye. The kinetic data conformed to the pseudo second order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔGº), enthalpy (Δº) and entropy (ΔSº) were evaluated and the negative values of ΔGº, ΔHº and ΔSº obtained indicate the spontaneous and exothermic nature of the adsorption process.

15

Comparison of adsorption of Cd(II) and Pb(II) ions on pure and chemically modified fly ashes

61%

Sočo E., Kalembkiewicz J.

Chemical and Process Engineering

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2016

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vol. 37

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issue 2

16

Kinetics and thermodynamics of gossypol extraction from defatted cottonseed meal by ethanol

61%

Saxena D., Sharma S., Sambi S.

Polish Journal of Chemical Technology

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2012

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vol. 14

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issue 2

29-34

EN

Gossypol is polyphenolic aldehyde, a toxic substance naturally present in cotton plant to protect it from insects, pests and diseases. Maximum gossypol is concentrated in the seed. After extraction of oil from the cottonseed, the defatted cottonseed meal which contains both the gossypol and proteinous matter is left behind. A number of attempts have been made using different solvents to extract gossypol from the seeds. However, all these efforts have remained in the realm of academic activity only as none of them could be commercialized. If a pilot plant or commercial scale plant is to be developed then the data on the kinetics and thermodynamics of the extraction process is required. In this study ethanol has been used as the solvent at temperature below 323K for removal of gossypol from the defatted seed. This study finds the effects of parameters viz. temperature, solvent to solid ratio (SR) and extraction time on the gossypol extraction efficiency. The data obtained are used to establish the kinetics and thermodynamics of the extraction process.

17

An approach to modeling and thermodynamic analysis of modern power engineering systems

61%

Kozaczka J., Kolat P.

Chemical and Process Engineering

|

2011

|

issue 4

18

Thermodynamics of specific protein-RNA interactions.

61%

Stolarski R.

Acta Biochimica Polonica

|

2003

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vol. 50

|

issue 2

297-318

EN

Description of the recognition specificity between proteins and nucleic acids at the level of molecular interactions is one of the most challenging tasks in biophysics. It is key to understanding the course and control of gene expression and to the application of the thus acquired knowledge in chemotherapy. This review presents experimental results of thermodynamic studies and a discussion of the role of thermodynamics in formation and stability of functional protein-RNA complexes, with a special attention to the interactions involving mRNA 5' cap and cap-binding proteins in the initiation of protein biosynthesis in the eukaryotic cell. A theoretical framework for analysis of the thermodynamic parameters of protein-nucleic acid association is also briefly surveyed. Overshadowed by more spectacular achievements in structural studies, the thermodynamic investigations are of equal importance for full comprehension of biopolymers' activity in a quantitative way. In this regard, thermodynamics gives a direct insight into the energetic and entropic characteristics of complex macromolecular systems in their natural environment, aqueous solution, and thus complements the structural view derived from X-ray crystallography and multidimensional NMR. Further development of the thermodynamic approach toward interpretation of recognition and binding specificity in terms of molecular biophysics requires more profound contribution from statistical mechanics.

19

Influence of thermodynamic mechanism of inter- facial adsorption on purifying air-conditioning engineering under intensification of electric field

61%

Chen Y.-Y.

Archives of Thermodynamics

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2016

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issue 4

20

Biosorption of Pb(II) by the resistant Enterobacter sp.: Investigated by kinetics, equilibriumand thermodynamics

57%

Liu L., Xia M., Hao J., Xu H., Song W., Liu L., Xia M., Hao J., Xu H., Song W.

Archives of Environmental Protection

|

2021

Refine search results

Elements of thermodynamics in RNA evolution.

Thermodynamics of a 3 - D charged rotating hairy black hole

Planck-scale corrections to Friedmann equation

Hydrodynamic cavitation: from theory towards a new experimental approach

On the thermodynamics of phase transitions in metal hydrides

An approach to modeling and thermodynamic analysis of modern power engineering systems

Hard-thermal-loop QCD trace anomaly

Interaction of anesthetic supplement thiopental with human serum albumin

Phonon-Induced Thermodynamic Properties of Ultra-narrow Wires

Free energy of helix propagation in short polyalanine chains determined from peptide growth simulations of La3+-binding model peptides. Comparison with experimental data

Excess thermodynamic quantities of D2O water calculated from its Raman O−D stretching spectra

The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent

A quantum version of the classical Szilard engine

Batch Adsorption Studies on Rice Husk with Methyl Violet Dye

Comparison of adsorption of Cd(II) and Pb(II) ions on pure and chemically modified fly ashes

Kinetics and thermodynamics of gossypol extraction from defatted cottonseed meal by ethanol

An approach to modeling and thermodynamic analysis of modern power engineering systems

Thermodynamics of specific protein-RNA interactions.

Influence of thermodynamic mechanism of inter- facial adsorption on purifying air-conditioning engineering under intensification of electric field

Biosorption of Pb(II) by the resistant Enterobacter sp.: Investigated by kinetics, equilibriumand thermodynamics