Large Positive Entropy Research Articles

The martensitic transformation, magnetocaloric effect, and magnetoresistance in high-Mn content Mn47+xNi43−xSn10 ferromagnetic shape memory alloys

A series of high-Mn content Mn47+xNi43−xSn10 (x=0, 1, 2, 3, 4, and 5) ferromagnetic shape memory alloys were prepared by arc melting method. The martensitic transformation were observed in these alloys, even the content of Mn is higher than 50 at. %. The phase transition temperature of these alloys can be adjusted by tuning the compositions of Ni and Mn. Large positive magnetic entropy change and negative magnetoresistance which originate from the magnetic-field-induced martensitic transformation are obtained in these alloys.

Sequence-Selective Binding of Phenazinium Dyes Phenosafranin and Safranin O to Guanine−Cytosine Deoxyribopolynucleotides: Spectroscopic and Thermodynamic Studies

The sequence selectivity of the DNA binding of the phenazinium dyes phenosafranin and safranin O have been investigated with four sequence-specific deoxyribopolynucleotides from spectroscopic and calorimetric studies. The alternating guanine-cytosine sequence selectivity of the dyes has been revealed from binding affinity values, circular dichroism, thermal melting, competition dialysis, and calorimetric results. The binding affinities of both the dyes to the polynucleotides were of the order of 10(5) M(-1), but the values were higher for the guanine-cytosine polynucleotides over adenine-thymine ones. Phenosafranin had a higher binding affinity compared to safranin O. Isothermal titration calorimetric studies revealed that the binding reactions were exothermic and favored by negative enthalpy and predominantly large positive entropy contributions in all cases except poly(dA)·poly(dT) where the profile was anomalous. Although charged, nonpolyelectrolytic contribution was revealed to be dominant to the free energy of binding. The negative heat capacity values obtained from the temperature dependence of enthalpy changes, which were higher for phenosafranin compared to safranin O, suggested significant hydrophobic contribution to the binding process. In aggregate, the data presents evidence for the alternating guanine-cytosine base pair selectivity of these phenazinium dyes and a stronger binding of phenosafranin over safranin O.

Mercury removal from wastewater using a poly(vinylalcohol)/poly(vinylimidazole) complexing membrane

Removal of Hg(II) ions from aqueous solutions by a novel complexing membrane was investigated by performing sorption and filtration experiments. The membrane, prepared by the technique of semi-interpenetrated polymer networks, consists in a matrix of poly(vinylalcohol), crosslinked by gaseous dibromoethane, that immobilizes chains of poly(vinylimidazole), a complexing polymer synthesised for this purpose. The morphology of the membrane was observed by scanning electron microscopy, showing an homogeneous structure, but surface unevenness. The dissolution of the membrane in water was slow and limited to 8% in 2 months, showing the efficiency of the crosslinking process. Efficient retention of Hg(II) was observed at pH 2.5. The kinetics of sorption were studied. The sorption equilibrium was satisfactorily represented by the Langmuir model. Isotherms performed at different temperatures allowed the calculation of the thermodynamical parameters. The sorption of mercury was endothermic, with a large positive entropy change that was ascribed to proton release. The effects of parameters such as water hardness, and the presence of complexing chloride anions were investigated, showing little influence on the retention ratio. Fast and efficient regeneration of the membrane was performed with a 0.5 M HNO 3 solution. The maximum capacity of the membrane was 120 mg Hg g −1, whereas the theoretical exchange capacity was 853 mg Hg g −1, showing that most internal complexing sites of the membrane were not accessible to mercury ions in sorption experiments. When used in the filtration mode, the elimination ratio of Hg(II) was ≥99.4% for solutions containing 91.6 or 17.5 mg Hg L −1.

Characterization of interactions of dihydrolipoamide dehydrogenase with its binding protein in the human pyruvate dehydrogenase complex

Unlike pyruvate dehydrogenase complexes (PDCs) from prokaryotes, PDCs from higher eukaryotes have an additional structural component, E3-binding protein (BP), for binding of dihydrolipoamide dehydrogenase (E3) in the complex. Based on the 3D structure of the subcomplex of human (h) E3 with the di-domain (L3S1) of hBP, the amino acid residues (H348, D413, Y438, and R447) of hE3 for binding to hBP were substituted singly by alanine or other residues. These substitutions did not have large effects on hE3 activity when measured in its free form. However, when these hE3 mutants were reconstituted in the complex, the PDC activity was significantly reduced to 9% for Y438A, 20% for Y438H, and 18% for D413A. The binding of hE3 mutants with L3S1 determined by isothermal titration calorimetry revealed that the binding affinities of the Y438A, Y438H, and D413A mutants to L3S1 were severely reduced (1019-, 607-, and 402-fold, respectively). Unlike wild-type hE3 the binding of the Y438A mutant to L3S1 was accompanied by an unfavorable enthalpy change and a large positive entropy change. These results indicate that hE3-Y438 and hE3-D413 play important roles in binding of hE3 to hBP.

Biophysical studies on the base specificity and energetics of the DNA interaction of photoactive dye thionine: Spectroscopic and calorimetric approach

In this study absorbance, fluorescence, circular dichroic spectroscopy, viscosity, thermal melting and calorimetric techniques were employed to understand the binding of the phenothiazinium dye, thionine, with deoxyribonucleic acids of varying base composition. Strong hypochromic and bathochromic effects and quenching of fluorescence were observed that showed strong binding of thionine to the DNAs. The binding parameters evaluated from Scatchard analysis through McGhee–von Hippel analysis showed that the binding was non-cooperative and affinities of the order of 10 5 M − 1. The results of ferrocyanide fluorescence quenching studies and viscosity experiments, taken together suggested the intercalation of thionine while thermal melting, differential scanning calorimetry and circular dichroic studies provided evidence for the thermal stabilization and conformational perturbations associated with the binding. The thermodynamic parameters elucidated through sensitive isothermal titration calorimetric studies suggested that the binding was exothermic, characterized by negative enthalpy and large positive entropy changes and that the non-electrostatic contributions play a significant role for thionine association to DNA. The heat capacity changes obtained from the temperature dependence of enthalpy changes gave negative values suggesting substantial hydrophobic contribution in the DNA binding process of thionine. Further, an observation of enthalpy–entropy compensation in the DNA binding also suggested the involvement of multiplicity of non covalent interactions in the binding process. The base specificity of the complexation and energetics of the interaction of thionine to DNA are obtained for the first time from this study.

Base pair specificity and energetics of binding of the phenazinium molecules phenosafranine and safranine-O to deoxyribonucleic acids: a comparative study

The base specificity and energetics of DNA binding of the phenazinium dyes phenosafranine and safranine-O have been studied using various biophysical tools. The guanine-cytosine base specificity of both compounds was established from binding affinity values and competition dialysis results and also from circular dichroism, thermal melting, and calorimetric studies. Both dyes bind to DNA with affinity of the order of 10(5) M(-1), but the values are significantly higher for the guanine-cytosine rich DNAs over adenine-thymine rich ones and for phenosafranine over safranine-O. Calorimetric studies revealed that the binding reactions were exothermic and favoured by negative enthalpy as well as predominantly large positive entropy contributions. The temperature dependence of enthalpy changes yielded negative heat capacity values, which were higher for phenosafranine, compared to safranine-O, suggesting substantial contribution from hydrophobic forces in the binding process. Enthalpy-entropy compensation behaviour was also observed for the binding of both dyes to DNAs, revealing the molecular aspects of the interaction. Taken together, the spectroscopic and calorimetric data reflect clearly the guanine-cytosine base specificity of these molecules and a stronger DNA binding of PSF over SO. The results also provide some insights into the role of a bulkier substituent in the phenazinium ring in the binding process.

First-principles thermodynamic framework for the evaluation of thermochemicalH2O- orCO2-splitting materials

We present an analysis of the equilibrium thermodynamics of two-step metal oxide-based water and carbon dioxide-splitting cycles. Within this theoretical framework, we propose a first-principles computational approach based on density-functional theory (DFT) for evaluating new materials for these cycles. Our treatment of redox-based gas-splitting chemistry is completely general so that the thermodynamic conclusions herein hold for all materials used for such a process and could easily be generalized to any gas as well. We determine the temperature and pressure regimes in which the thermal reduction (TR) and gas-splitting (GS) steps of these cycles are thermodynamically favorable in terms of the enthalpy and entropy of oxide reduction, which represents a useful materials design goal. We show that several driving forces, including low TR pressure and a large positive solid-state entropy of reduction of the oxide, have the potential to enable future, more promising two-step gas-splitting cycles. Finally, we demonstrate a practical computational methodology for efficiently screening new materials for gas-splitting applications and find that first-principles DFT calculations can provide very accurate predictions of high-temperature thermodynamic properties relevant to gas splitting.

Large low-field inverse magnetocaloric effect near room temperature in Ni50−x Mn37+x In13 Heusler alloys

Low field inverse magnetocaloric effect (IMCE) associated with first-order martensitic transition in Ni50−x Mn37+x In13 (x=3,4,5) alloys was investigated. By tuning the composition of Ni/Mn, large change in the magnetization occurring between martensite and austenite phases in a narrow temperature interval was achieved, which results in large IMCE. Under low magnetic field change of 2 T, a large positive magnetic entropy change (ΔS M ) of 23.5 J/kg K with a net refrigeration capacity of 53 J/kg was obtained near room temperature (308 K) in the x=3 alloy. The results show that a small variation in Ni/Mn ratio significantly influences the martensitic transition temperature and the associated magnetic and magnetocaloric properties.

Activation Parameters for Heme−NO Binding in Alcaligenes xylosoxidans Cytochrome c′: The Putative Dinitrosyl Intermediate Forms via a Dissociative Mechanism

The bacterial heme protein Alcaligenes xylosoxidans cytochrome c' (AXCP) forms a novel five-coordinate heme-nitrosyl (5c-NO) complex in which NO resides at the proximal heme face in place of the endogenous protein ligand. Intriguingly, AXCP shares NO-binding properties with the eukaryotic NO-sensor, soluble guanylate cyclase (sGC), including 5c-NO formation via two NO-dependent reactions. For both proteins, a model has been proposed in which NO binds to the vacant distal face to form a transient six-coordinate heme-nitrosyl (6c-NO) species, which then converts to a proximal 5c-NO complex via a putative dinitrosyl intermediate. To shed light on this novel reaction mechanism, activation parameters have been determined for distal and proximal NO-binding reactions in AXCP from the effect of temperature and hydrostatic pressure on rate constants. The unusually slow 6c-NO formation reaction has a near-zero entropy of activation and a positive volume of activation (DeltaV(double dagger) = +14.1 cm(3) mol(-1)), consistent with a rate-determining step involving movement of the Leu 16 residue to allow NO binding to the crowded distal site. For the 6c-NO --> 5c-NO conversion, the large positive entropy of activation (DeltaS(double dagger) = +103 J K(-1) mol(-1)) and volume of activation (DeltaV(double dagger) = +24.1 cm(3) mol(-1)) suggest that the putative dinitrosyl intermediate forms via a dissociative mechanism in which the endogenous His ligand dissociates prior to the attack of the second NO molecule on the proximal heme face. These results have important implications for distal vs proximal NO binding in AXCP, as well as mechanisms of 5c-NO formation in heme proteins.

Effects of Temperature and Emulsifier Concentration on α-Tocopherol Distribution in a Stirred, Fluid, Emulsion. Thermodynamics of α-Tocopherol Transfer between the Oil and Interfacial Regions

The combined linear sweep voltammetry (LSV)/pseudophase kinetic model method was used to obtain the first estimates of the free energies, enthalpy, and entropies of transfer of alpha-tocopherol (TOC) between the oil and interfacial regions of fluid, opaque, emulsions of n-octane, acidic water, and the nonionic surfactant hexaethyleneglycol mono dodecyl ether (C12E6) from the temperature dependence of TOC's partition constant. Determining structure-reactivity relationships for chemical reactions in emulsions is difficult because traditional methods for monitoring reactions are unsuitable and because the partitioning of reactive components between the oil, interfacial, and aqueous regions of opaque emulsions are difficult to measure. The dependence of the observed rate constant, k(obs), for the reaction of an arenediazonium probe, 16-ArN2+, with TOC was determined as a function of C12E6 volume fraction. The pseudophase kinetic model was used to estimate the interfacial rate constant, k1, and the partition constants of antioxidants between the oil and interfacial, Po(I), regions in the emulsion from k(obs) versus phiI profiles. The thermodynamic parameters of transfer from the oil to the interfacial region at a series of temperatures were respectively obtained from the PoI values (deltaGT0,O-->I), by the van't Hoff method (deltaHT0,O-->I), and from the Gibbs equation (deltaST0,O-->I). The free energy of transfer is spontaneous, and a large positive entropy of transfer dominates a positive enthalpy of transfer, indicating that the TOC headgroup disrupts the structure of the interfacial region in its immediate vicinity upon transfer from n-octane. The methods described here are applicable to any bimolecular reaction in emulsions in which one of the reactants is restricted to the interfacial region and the rate of its reaction with a second component can be monitored electrochemically.

Insights Into The Energetics Of Neuronal SNARE Complex Formation

Eukaryotic cells transport material between intracellular compartments by vesicles that bud from a donor and afterwards fuse with a target organelle. Best-studied is the molecular machinery that drives the Ca2+-dependent release of neurotransmitters from synaptic vesicles. Key players in the exocytotic fusion are three proteins synaptobrevin 2, syntaxin 1a, and SNAP-25. Synaptobrevin resides in synaptic vesicles, whereas syntaxin and SNAP-25 are anchored in the plasma membrane. They belong to the so-called SNARE protein family, which members are involved in all other vesicle fusion steps. SNARE proteins are tail-anchored membrane proteins that assemble into a stable membrane-bridging complex. As SNARE assembly is accompanied by extensive structural rearrangements from mostly unstructured monomers into a tightly packed parallel four-helix bundle, it is thought that zipper-like formation of the SNARE bundle between opposing membranes provides the energy that drives fusion. It is unclear, however, whether the assembly energy indeed suffices for membrane merger. Unfortunately, a marked hysteresis in the folding and unfolding transition of the SNARE complex prevents the direct determination of the free energy of assembly. We have now investigated the assembly process by isothermal titration calorimetry. We found that the structural changes upon assembly are reflected in extremely large favorable enthalpy changes, counterbalanced by a large positive entropy change. Moreover, as SNARE complex is essentially irreversible, we made use of the fact that assembly in vitro proceeds in discrete steps. This allowed us to assess the energetics of each assembly step individually.

DNA intercalation of methylene blue and quinacrine: new insights into base and sequence specificity from structural and thermodynamic studies with polynucleotides

The binding of the known DNA intercalators methylene blue and quinacrine with four sequence specific polynucleotides, viz. poly(dG-dC).poly(dG-dC), poly(dG).poly(dC), poly(dA-dT).poly(dA-dT) and poly(dA).poly(dT), have been compared using absorbance, fluorescence, competition dialysis and thermal melting and the thermodynamic aspects of the interaction studied. In all the cases, non-cooperative binding phenomena obeying neighbor exclusion principle was observed though the affinity was remarkably higher for quinacrine and the nature of the binding was characterized to be true intercalation. The data on the salt dependence of binding derived from the plot of log Kvs. log[Na(+)] revealed a slope of around 1.0, consistent with the values predicted by the theories for the binding of monovalent cations, and contained contributions from polyelectrolytic and non-polyelectrolytic forces. The bindings were characterized by strong stabilization of the polynucleotides against thermal strand separation in both optical melting as well as differential scanning calorimetry studies. The data analyzed from the thermal melting and isothermal titration calorimetry studies were in close proximity to those obtained from absorption spectral titration data. Isothermal titration calorimetry results revealed the bindings to poly(dG-dC).poly(dG-dC), poly(dG).poly(dC) and poly(dA-dT).poly(dA-dT) to be exothermic and favoured by both negative enthalpy and large favourable positive entropy changes, while that to poly(dA).poly(dT) was endothermic and entropy driven. The heat capacity changes obtained from temperature dependence of enthalpy gave negative values to all polynucleotides. New insights on the molecular aspects of interaction of these molecules to DNA have emerged from these studies.

The phase transitions, magnetocaloric effect, and magnetoresistance in Co doped Ni–Mn–Sb ferromagnetic shape memory alloys

The phase transitions, magnetocaloric effect, and magnetoresistance in Ni50−xCoxMn39Sb11 (x=0–11) ferromagnetic shape memory alloys were investigated. The temperatures of martensitic transformation and magnetic transition in austenitic phase depend strongly on the Co concentration, while the magnetic transition temperature in martensitic phase shows small dependence on alloy composition. For 7≤x≤9, the martensitic transformation is accompanied by a sudden change in magnetization. Large positive magnetic entropy changes and negative magnetoresistance near room temperature, which originate from the magnetic-field-induced transformation from the weak-magnetic high-resistance martensitic phase to the ferromagnetic low-resistance parent phase, are observed in these alloys. Our results indicate the potential application of Ni50−xCoxMn39Sb11 alloys in magnetic refrigeration and magnetic sensors.

Anomalous field dependence of the inverse magnetocaloric effect in Ce(Fe 0.93Ru 0.07) 2

A summary of detailed isothermal magnetization along with the ac susceptibility measurements on Ce(Fe 0.93Ru 0.07) 2 is presented. Near the first-order transition, i.e. near 110 K, Ce(Fe 0.93Ru 0.07) 2 displays a large positive magnetic entropy change, ΔSm, of 7.8 J/kg K in fields of only 2 T, i.e. it displays a strong inverse magnetocaloric (MCE) effect, as expected, on entering an antiferromagnetic (AF) state. However, the variation of the magnitude and width of this entropy change with field are anomalous when compared with model predictions, the former increasing with applied field below 2 T, while the latter exceeds 60 K in a field of 8 T.

Extracting stoichiometry, thermodynamics, and kinetics for the interaction of DNA with cadmium ion by capillary electrophoresis on‐line coupled with electrothermal atomic absorption spectrometry

Understanding the binding of cadmium with DNA is of great importance for elucidating the mechanism of cadmium genotoxicity and carcinogenicity. In the present work, CE on-line coupled with electrothermal atomic absorption spectrometry was employed to study the binding electrophoretic behaviors, stoichiometry, thermodynamics, and kinetics for the interaction of cadmium cation (Cd(II)) with DNA. The stoichiometry (Cd(II) to DNA (as the concentration of base pairs)) for the interaction was determined to be 1:5. Two types of binding sites on DNA were observed with the binding constants of 10(6) and 10(5) L/mol, respectively, showing strong affinity of Cd(II) to DNA. The interaction of Cd(II) with both types of binding sites on DNA were driven by negative enthalpy change with a large positive entropy change. The binding of Cd(II) to DNA followed a first-order kinetics for Cd(II) with the apparent activation energy of 45.7 +/- 1.9 kJ/mol. The results obtained in present investigation would be helpful to understanding the genotoxicity and carcinogenicity of cadmium.

Investigation of martensitic transition and inverse magnetocaloric property in Ni-Mn-Sn Heusler alloys

The martensitic transition and magnetocaloric property in Ni50Mn25+xSn25-x (x=11, 12) Heusler alloys were investigated by means of structure and magnetism measurements. The results show that the antiferromagnetic interaction strengthens in the martensitic state, leading to the coexistence of ferromagnetic and antiferromagnetic interaction in this state, which is different from the magnetic property of austenitic state in these alloys. Furthermore, based on Maxwell equation, the inverse magnetocaloric property near martensitic transition temperature of this system was studied. It was found that large positive magnetic entropy change (ΔSM) depends on both magnetic jumping (ΔM) and temperature region during martensitic transition.

The Role of Secondary Structure in the Entropically Driven Amelogenin Self-Assembly

Amelogenin, the major extracellular enamel matrix protein, plays critical roles in controlling enamel mineralization. This generally hydrophobic protein self-assembles to form nanosphere structures under certain solution conditions. To gain clearer insight into the mechanisms of amelogenin self-assembly, we first investigated the occurrences of secondary structures within its sequence. By applying isothermal titration calorimetry (ITC), we determined the thermodynamic parameters associated with protein-protein interactions and with conformational changes during self-assembly. The recombinant porcine full length (rP172) and a truncated amelogenin lacking the hydrophilic C-terminal (rP148) were used. Circular dichroism (CD) measurements performed at low concentrations (<5 μM) revealed the presence of the polyproline-type II (PPII) conformation in both amelogenins in addition to α-helix and unordered conformations. Structural transition from PPII/unordered to β-sheet was observed for both proteins at higher concentrations (>62.5 μM) and upon self-assembly. ITC measurements indicated that the self-assembly of rP172 and rP148 is entropically driven (+Δ S A) and energetically favorable (−Δ G A). The magnitude of enthalpy (Δ H A) and entropy changes of assembly (Δ S A) were smaller for rP148 than rP172, whereas the Gibbs free energy change of assembly (Δ G A) was not significantly different. It was found that rP172 had higher PPII content than rP148, and the monomer-multimer equilibrium for rP172 was observed in a narrower protein concentration range when compared to rP148. The large positive enthalpy and entropy changes in both cases are attributed to the release of ordered water molecules and the associated entropy gain (due to the hydrophobic effect). These findings suggest that PPII conformation plays an important role in amelogenin self-assembly and that rP172 assembly is more favorable than rP148. The data are direct evidence for the notion that hydrophobic interactions are the main driving force for amelogenin self-assembly.

Magnetocaloric effect and magnetic-field-induced shape recovery effect at room temperature in ferromagnetic Heusler alloy Ni–Mn–Sb

The martensitic transition, magnetocaloric effect (MCE) and shape memory effect (MSE) of ferromagnetic Heusler alloys Ni50Mn50−xSbx (x = 12, 13 and 14) have been investigated. A large positive magnetic entropy change ΔSM was observed in the vicinity of the martensitic transition. The maximum value of ΔSM is 9.1 J kg−1 K−1 in Ni50Mn37Sb13 at 287 K for a magnetic field change of 5 T. This change originates from the first-order transition from a low-temperature weak-magnetic martensitic phase to a high-temperature ferromagnetic parent phase. A magnetic-field-induced shape recovery strain of about 15 ppm at room temperature and at a relatively low magnetic field (1.2 T) was observed to accompany the reverse martensitic transformation. The large field-induced MCE and MSE in the NiMnSb system make it a promising material for room-temperature application.

Characteristics of DEAE-dextran-MMA graft copolymer as a nonviral gene carrier

A stable and soapless latex of diethylaminoethyl-dextran-methyl methacrylate (DEAE-dextran-MMA) graft copolymer (DDMC) has been developed for nonviral gene delivery vectors that are possible to autoclave. DDMC relatively easily formed a polyion complex between DNA and DDMC by the hydrophobic force of graft poly(MMA) depending on its large positive entropy change (ΔS). DDMC has been confirmed as having a high protection facility for DNase by DNase degradation test.Transfection activity was determined using the β-galactosidase assay, and a higher value of 16 times or more was confirmed for the DDMC samples in comparison with one of the starting DEAE-dextran hydrochloride samples. The resulting DDMC, having an amphiphilic domain so as to form a polymer micelle, should become a stable latex with a hydrophilic-hydrophobic microseparated domain. The complex of DDMC and plasmid DNA may be formed on the spherical structure of the amphiphilic microseparated domain of DDMC and have a good affinity to the cell membrane. The infrared absorption spectrum shift to a high-energy direction at around 3450 cm –1, because of the complexes between DNA and DDMC, may cause the formation of more compact structures, not only by a coulomb force between the phosphoric acid of DNA and the DEAE group of DEAE-dextran copolymer but also by a force from the multi-intermolecule hydrogen bond in the backbone polymer DEAE-dextran and a hydrophobic force from the graft poly(MMA) in DDMC. It is thus concluded that DNA condensation may possibly have a high transfection efficiency via DDMC. The high efficiency of this graft copolymer, which is sterilized by an autoclave, may thus make it a valuable tool for safe gene delivery.

Numerical simulation of methane fuelled cogenerative SOFCs for the production of synthesis gas and electrical energy

Numerical simulation has been used to show the feasibility of the autothermal cogeneration of synthesis gas and electricity in a solid oxide fuel cell (SOFC) by the electrochemical partial oxidation of CH 4 . Owing to the large positive entropy change of the CH 4 partial oxidation reaction and its low heating value, severe cooling effect is being induced in the SOFC due to heat absorbance by the reaction products. For this reason the autothermal operation of the SOFC reactor cannot be secured. As it is shown this can be overcome by combining the dynamic operation of the SOFC under forced periodic reversal of the flow and the bleeding of a small amount of CH 4 ( < 2.5 % ) in the oxidant stream (cathode). In this respect the catalytic combustion of CH 4 , on the perovskite cathodic electrode, provides the necessary energy demand so that in combination with flow reversal operation the SOFC is maintained ignited even at inlet temperature as low as 300 K. It is shown that the overall thermodynamic efficiency of the process can by far exceed unity ( η ′ > 2 ) , thus revealing the unique property of the SOFCs to produce high-quality energy and useful chemicals.