Showing papers by "Indian Association for the Cultivation of Science published in 2015"
TL;DR: Numerical studies on a system of interacting one-dimensional bosons and the quantum random energy model, as well as simple physical pictures accounting for those results, find that the presence of a mobility edge anywhere in the spectrum is enough to lead to delocalization for any driving strength and frequency.
Abstract: We study many-body localized quantum systems subject to periodic driving. We find that the presence of a mobility edge anywhere in the spectrum is enough to lead to delocalization for any driving strength and frequency. By contrast, for a fully localized many-body system, a delocalization transition occurs at a finite driving frequency. We present numerical studies on a system of interacting one-dimensional bosons and the quantum random energy model, as well as simple physical pictures accounting for those results.
357 citations
TL;DR: A new triazine functionalized hexagonally ordered covalent organic polymer (TRITER-1) has been synthesized via the Schiff-base condensation reaction between a tailor made triamine 1,3,5-tris-(4-aminophenyl)triazine (TAPT) and terephthaldehyde.
246 citations
TL;DR: Graphene-based hybrid nanostructures have recently emerged as a new class of functional materials for light-energy conversion and storage and can provide a valuable opportunity to explore novel hybrid materials with superior visible-light-induced catalytic activity.
Abstract: Graphene-based hybrid nanostructures have recently emerged as a new class of functional materials for light-energy conversion and storage. Here, we have synthesized reduced graphene oxide (RGO)–semiconductor composites to improve the efficiency of photocatalysis. Zero-dimensional CdS nanoparticles (0D), one-dimensional CdS nanorods (1D), and two-dimensional CdS nanosheets (2D) are grafted on the RGO sheet (2D) by a surface modification method using 4-aminothiophenol (4-ATP). Structural analysis confirms the attachment of CdS nanocrystals with RGO, and the strong electronic interaction is found in the case of a CdS nanosheet and RGO, which has an influence on photocatalytic properties. The degradation of dye under visible light varies with changing the dimension of nanocrystals, and the catalytic activity of the CdS NS/RGO composite is ∼4 times higher than that of CdS nanoparticle/RGO and 3.4 times higher than that of CdS nanorod/RGO composite samples. The catalytic activity of the CdS nanosheet/RGO compos...
237 citations
TL;DR: The latest developments in the synthetic chemistry in designing nano heterostructures are reported and their photocatalytic activities in organic dye degradation/reduction and/or photoc atalytic water splitting for generation of hydrogen are discussed.
Abstract: For fast separation of the photogenerated charge carriers, metal semiconductor heterostructures have emerged as one of the leading materials in recent years. Among these, metal Au coupled with low bandgap semiconductors remain as ideal materials where both can absorb the solar light in the visible region. It is also established that on excitation, the plasmonic state of gold interacts with excited state of semiconductor and helps for the delocalization of the photogenerated electrons. Focusing these materials where electron transfer preferably occurs from semiconductor to metal Au on excitation, in this Perspective, we report the latest developments in the synthetic chemistry in designing such nano heterostructures and discuss their photocatalytic activities in organic dye degradation/reduction and/or photocatalytic water splitting for generation of hydrogen. Among these, materials such as Au-CZTS, Au-SnS, Au–Bi2S3, Au-ZnSe, and so forth are emphasized, and their formation chemistry as well as their photo...
233 citations
TL;DR: Synthesized novel fibrous composites show an excellent specific capacitance value and moderate cyclic stability with a retention of life time of 80.1% after 3000 cycles.
217 citations
TL;DR: The results indicate that small size, ease of custom synthesis, thixotropic nature makes these amyloid-based hydrogels ideally suited for biomaterial/nanotechnology applications.
157 citations
TL;DR: In this article, the effect of different plasticizers, such as poly ethylene glycol, propylene carbonate, ethylene carbonates and dimethyl carbonate on the ionic conductivity and dielectric relaxation of PEO-LiClO4 solid polymer electrolytes was reported.
147 citations
TL;DR: It is demonstrated that on mitotic entry, kinetochores in cultured human cells form large crescents that subsequently compact into discrete structures on opposite sides of the centromere, which can explain the robustness of spindle assembly and the functional significance of enlarged kinetchores.
Abstract: Mitotic spindle formation relies on the stochastic capture of microtubules at kinetochores. Kinetochore architecture affects the efficiency and fidelity of this process with large kinetochores expected to accelerate assembly at the expense of accuracy, and smaller kinetochores to suppress errors at the expense of efficiency. We demonstrate that on mitotic entry, kinetochores in cultured human cells form large crescents that subsequently compact into discrete structures on opposite sides of the centromere. This compaction occurs only after the formation of end-on microtubule attachments. Live-cell microscopy reveals that centromere rotation mediated by lateral kinetochore-microtubule interactions precedes the formation of end-on attachments and kinetochore compaction. Computational analyses of kinetochore expansion-compaction in the context of lateral interactions correctly predict experimentally observed spindle assembly times with reasonable error rates. The computational model suggests that larger kinetochores reduce both errors and assembly times, which can explain the robustness of spindle assembly and the functional significance of enlarged kinetochores.
137 citations
TL;DR: A comprehensive overview of mesoporous solids, the most remarkable member of the nanoporous family of materials, the general strategy for their syntheses and application of functionalized porous materials in liquid phase catalytic reactions is provided in this paper.
Abstract: Due to their unprecedented intrinsic structural features, like tunable pore diameter of nanoscale dimensions, huge BET surface areas and good flexibility to recognize/accommodate various functional groups and metals onto the surface, an inevitable linkage of nanoporous materials with catalysis has been built-up over the past few decades. As a result of which, a huge number of communications and articles dealing with these materials with nanoscale porosity have come to light. In this review, our objective is to provide a comprehensive overview of mesoporous solids, the most remarkable member of the nanoporous family of materials, the general strategy for their syntheses and application of functionalized porous materials in liquid phase catalytic reactions. In the latter part, the role of catalytic centres in various organic transformations over these functionalized mesoporous materials and their economical, environmental and industrial aspects are described in detail.
132 citations
TL;DR: In this paper, the authors show that the sequential replacement of C by Ge in benzene leads to increasing buckling with the maximal buckling distance (d = 0.61 A) in Ge6H6.
Abstract: The heavier analogues of graphene, namely silicene and germanene, are known to be buckled. Such buckling leads to interesting properties like direct band gap in hydrogenated germanene, known as germanane. This article shows that the sequential replacement of C by Ge in benzene leads to increasing buckling with the maximal buckling distance (d = 0.61 A) in Ge6H6. The origin of such buckling induced lowering of symmetry (D6h → D3d) is traced to pseudo Jahn–Teller (PJT) distortion along the b2g normal mode arising out of mixing of the nondegenerate (A1g) ground state with low lying (Δ0 = 4.36 eV) excited state of B2g symmetry. Buckling also leads to enhanced chemical reactivity of germanene toward hydrogen to form germanane. The large affinity of germanene toward hydrogenation explains the experimental synthesis of exfoliated layers of germanane by Goldberger and co-workers [ACS Nano 2013, 7, 4414−4421]. Germanene → germanane formation leads to the opening up of a large band gap making hydrogenation a chemic...
125 citations
TL;DR: Ag-NP-decorated BDP fibers (BDP@Ag composites) have been evolved as a sensitive materials for the detection of trace amounts of 4-mercaptobenzoic acid and rhodamine 6G as an analyte of surface-enhanced Raman scattering (SERS), and the detection limit is down to nanomolar concentrations with excellent recyclability.
Abstract: Facile synthesis of polyaniline@Ag composite has been successfully demonstrated by a simple solution-dipping method using high-aspect-ratio benzene tetracarboxylic acid-doped polyaniline (BDP) fiber as a nontoxic reducing agent as well as template cum stabilizer. In BDP@Ag composite, BDP fibers are decorated with spherical Ag nanoparticles (Ag NPs), and the population of Ag NPs on BDP fibers is controlled by changing the molar concentration of AgNO3. Importantly, Ag-NP-decorated BDP fibers (BDP@Ag composites) have been evolved as a sensitive materials for the detection of trace amounts of 4-mercaptobenzoic acid and rhodamine 6G as an analyte of surface-enhanced Raman scattering (SERS), and the detection limit is down to nanomolar concentrations with excellent recyclability. Furthermore, synthesized BDP@Ag composites are applied simultaneously as an active SERS substrate and a superior catalyst for reduction of 4-nitrothiophenol.
TL;DR: Upon sulfonation HMP-1 yielded a very efficient solid acid catalyst for the production of biodiesels via esterification/transesterification of free fatty acids (FFA)/esters at room temperature.
TL;DR: In this article, a facile and rapid synthesis of core-shell type magnetite-chitosan microsphere decorated with silver nanoparticles (MCSM) is described.
Abstract: A facile and rapid synthesis of core–shell type magnetite-chitosan microsphere decorated with silver nanoparticles (MCSM) is described. The composition and structure of the as-synthesized microsphere characterized by various spectroscopic and microscopic techniques demonstrated formation of 3.63 ± 0.76 μm MCSM with decoration of silver nanoparticles (AgNPs) having 16 ± 2.5 nm size. The thermogravimetric analysis (TGA) data showed good thermal stability, whereas vibrating sample magnetometry (VSM) analysis indicated the superparamagnetic behavior of the as-synthesized microsphere. The adsorptive removal and antimicrobial property of MCSM was explored for eco-friendly and cost-effective water purification. The MCSM removed 99.99% microbial contaminants and 99.5% of dyes from single as well as multicomponent systems from water bodies efficiently. Furthermore, the dye removal capacity of MCSM (qe = 271.2 ± 14.5 mg/g) was found to be higher compared to the other nanoadsorbents attributing to the high effective...
TL;DR: In this paper, a method for preparing an elusive Co3O4/TiO2 p-n heterojunction using Co-based metal organic frameworks (Co-MOFs) as a TiO2-absorbent cum sacrificial template for nanocomposite formation was reported.
Abstract: The present work reports a novel method for preparing an elusive Co3O4/TiO2 p–n heterojunction using Co-based metal organic frameworks (Co-MOFs) as a TiO2-absorbent cum sacrificial template for nanocomposite formation. Four new Co-MOFs based on a bispyrazole ligand and different carboxylic acids, with a wide variety of dimensionality, porosity and surface characteristics, were exploited for this purpose. We detail here the synthesis of cobalt MOFs using the hydro(solvo)thermal method and structural characterization by single crystal X-ray diffraction (XRD). We have also successfully demonstrated our strategy of using MOFs for fabricating superior p–n diode-type Co3O4/TiO2 hetero-nanocomposites for photocatalytic hydrogen production. The characterization results suggested that the nanocomposites consisted of highly crystalline desired anatase TiO2 nanoparticles and spinel Co3O4-like species. The nanocomposite with 2 wt% Co loading exhibited the maximum photoactivity with a hydrogen evolution rate of ∼7 mmol g−1 h−1 under UV-vis light irradiation. The above results indicate that the present preparative strategy is an amenable route for the synthesis of desirable synergistic photocatalysts combining a remarkable reactivity relevant to solar energy conversion.
TL;DR: It is hypothesize that a high density of Zn-Schiff base/salen units present in the porous polymer network is responsible for the exceptionally high catalytic performance of ZN@SBMMP.
TL;DR: Surprisingly, several (local) emissive regions within MAPbI3-x(SCN)x microcrystals are found to be optically unstable under photoirradiation, and display unambiguous temporal intermittency in emission (blinking), which is extremely unusual and intriguing.
Abstract: Pseudohalide thiocyanate anion (SCN–) has been used as a dopant in a methylammonium lead tri-iodide (MAPbI3) framework, aiming for its use as an absorber layer for photovoltaic applications. The substitution of SCN– pseudohalide anion, as verified using Fourier transform infrared (FT-IR) spectroscopy, results in a comprehensive effect on the optical properties of the original material. Photoluminescence measurements at room temperature reveal a significant enhancement in the emission quantum yield of MAPbI3–x(SCN)x as compared to MAPbI3, suggestive of suppression of nonradiative channels. This increased intensity is attributed to a highly edge specific emission from MAPbI3–x(SCN)x microcrystals as revealed by photoluminescence microscopy. Fluoresence lifetime imaging measurements further established contrasting carrier recombination dynamics for grain boundaries and the bulk of the doped material. Spatially resolved emission spectroscopy on individual microcrystals of MAPbI3–x(SCN)x reveals that the optic...
TL;DR: Aligned C60NWs could be transferred onto many different flat substrates, and, in this case, aligned C60 NWs on glass substrates were employed as a scaffold for cell culture, indicating their potential for use in biomedical applications.
Abstract: A versatile method for the rapid fabrication of aligned fullerene C60 nanowhiskers (C60NWs) at the air–water interface is presented. This method is based on the vortex motion of a subphase (water), which directs floating C60NWs to align on the water surface according to the direction of rotational flow. Aligned C60NWs could be transferred onto many different flat substrates, and, in this case, aligned C60NWs on glass substrates were employed as a scaffold for cell culture. Bone forming human osteoblast MG63 cells adhered well to the C60NWs, and their growth was found to be oriented with the axis of the aligned C60NWs. Cells grown on aligned C60NWs were more highly oriented with the axis of alignment than when grown on randomly oriented nanowhiskers. A study of cell proliferation on the C60NWs revealed their low toxicity, indicating their potential for use in biomedical applications.
TL;DR: The reduction of CO2 by an iron porphyrin complex with a hydrogen bonding distal pocket involves at least two intermediates and the facile heterolytic cleavage of the C-OH bond in intermediate II requires strong acids.
Abstract: The reduction of CO2 by an iron porphyrin complex with a hydrogen bonding distal pocket involves at least two intermediates. The resonance Raman data of intermediate I, which could only be stabilized at −95 °C, indicates that it is a Fe(II)–CO22– adduct and is followed by an another intermediate II at −80 °C where the bound CO2 in intermediate I is protonated to form a Fe(II)–COOH species. While the initial protonation can be achieved using weak proton sources like MeOH and PhOH, the facile heterolytic cleavage of the C–OH bond in intermediate II requires strong acids.
TL;DR: In this paper, the synthesis of l-serine-based zwitterionic polymers, poly(l-serinyl acrylate)s (PSAs), of controllable molecular weights and low polydispersities via reversible addition-fragmentation chain transfer (RAFT) polymerization in water at 70 °C is described.
Abstract: The synthesis of l-serine-based zwitterionic polymers, poly(l-serinyl acrylate)s (PSAs), of controllable molecular weights and low polydispersities via reversible addition–fragmentation chain transfer (RAFT) polymerization in water at 70 °C is described. The obtained homopolymer PSA exhibits dual responsiveness toward pH and temperature in aqueous solution. The PSA exhibits an isoelectric point near pH 2.85 where the PSA molecules exist in its zwitterionic form. In the pH range of 2.3–3.5, the aqueous PSA solution appears as a two-phase system due to the formation of insoluble aggregates through the intra- and intermolecular electrostatic interaction between the pendent ammonium and carboxylate groups of the neighboring zwitterionic PSA molecules. Furthermore, in this pH range, the two-phase PSA solution becomes one-phase upon heating, exhibiting distinct reversible upper critical solution temperature (UCST)-type phase transition. The cloud point (Tp) is found to increase with increasing molecular weights...
TL;DR: In this article, a nanoporous polytriphenylamine (PPTPA-1) was synthesized by a simple one-step oxidative polymerization pathway, which showed very high surface acidity and it was successfully employed as a solid acid catalyst for direct conversion of sugar to HMF.
Abstract: Sustainable supply of energy is one of the biggest challenges today. The conversion of energy from any abundant and renewable resources would be an ideal solution for this ever increasing demand of sustainable energy. Biomass provides a potential energy alternative through the platform chemical 5-hydroxymethylfurfural (HMF), which is considered as a sustainable source for liquid fuels and commodity chemicals. Herein, we report the synthesis of a nanoporous polytriphenylamine (PPTPA-1) having high surface area (1437 m2 g−1) by a simple one-step oxidative polymerization pathway. Upon sulfonation of PPTPA-1, the sulfonated polymer SPPTPA-1 showed very high surface acidity and it has been successfully employed as a solid acid catalyst for direct conversion of sugar to HMF. Both PPTPA-1 and SPPTPA-1 materials have distinct nanofiber morphologies and they are characterized thoroughly by using powder XRD, FTIR spectroscopy, 13C solid state magic-angle-spinning NMR spectrometry, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and N2 sorption techniques. We have optimized the HMF yields by using different carbohydrate sources and estimated the recycling efficiency of the catalyst.
TL;DR: This simple transformation demonstrates a broad substrate scope with respect to aldehydes and nitrogen heterocycles, enabling the introduction of several medicinally important yet challenging alkyl moieties to the different classes of heterocyclic bases in good to excellent yields.
Abstract: An operationally simple and economical method for the direct alkylation of heteroaromatic bases employing readily available aldehydes as alkyl radical precursors and molecular oxygen as a reagent is presented. This simple transformation demonstrates a broad substrate scope with respect to aldehydes and nitrogen heterocycles, enabling the introduction of several medicinally important yet challenging alkyl moieties, such as ethyl, isopropyl, tert-butyl, and cyclohexyl to the different classes of heterocyclic bases in good to excellent yields.
TL;DR: Molecular relaxations phenomena due to the constraint associated with the grafting have been revealed using spin–lattice relaxation tine (T1) and shifting of peak position in tan δ curve toward lower temperature in dynamic mechanical measurement at constant frequency indicating flexible nature of graft copolymers as compared to pure CHT.
Abstract: The present investigation focuses on the grafting of chitosan (CHT) with diisocyanate terminated polyurethane. Solid state 13C NMR spectroscopy confirms the grafting reaction and the degree of substitution (DS) was calculated from the deconvoluted area of the corresponding NMR peak. Solubility studies, swelling behavior and contact angle measurements support the hydrophobic chemical modification on CHT molecules and higher DS leads to the cross-linking of CHT molecules having polyurethane bridges resulting insolubility and regulated swelling in the graft copolymer. Molecular relaxations phenomena due to the constraint associated with the grafting have been revealed using spin–lattice relaxation tine (T1) and shifting of peak position in tan δ curve toward lower temperature in dynamic mechanical measurement at constant frequency indicating flexible nature of graft copolymers as compared to pure CHT. The sustained drug delivery has been achieved using graft copolymers vis-a-vis pure CHT following the Fickia...
TL;DR: In this article, a generalization of the results obtained in the context of general relativity generalize to Lanczos-Lovelock gravity in a straightforward but non-trivial manner.
Abstract: The deep connection between gravitational dynamics and horizon thermodynamics leads to several intriguing features in general relativity. In this chapter we provide a generalization of several of such results to Lanczos-Lovelock gravity. To our expectation it turns out that most of the results obtained in the context of general relativity generalize to Lanczos-Lovelock gravity in a straightforward but non-trivial manner. First, we provide an alternative and more general derivation of the connection between Noether charge for a specific time evolution vector field and gravitational heat density of the boundary surface. Taking a cue from this, we have introduced naturally defined four-momentum current associated with gravity and matter energy momentum tensor for both Lanczos-Lovelock Lagrangian. Then, we consider the concepts of Noether charge for null boundaries in Lanczos-Lovelock gravity by providing a direct generalization of previous results derived in the context of general relativity. Further we have shown that gravitational field equations for arbitrary static and spherically symmetric spacetimes with horizon can be written as a thermodynamic identity in the near horizon limit, transcending general relativity.
TL;DR: Graphene and graphene based composites might be used as potential candidates for CB-hMSCs differentiation and proliferation for human skeletal muscle tissue regeneration and self-aligned myotubesformation similar to natural orientation.
Abstract: Recently graphene and graphene based composites are emerging as better materials to fabricate scaffolds. Addition of graphene oxide (GO) nanoplatelets (GOnPs) in bioactive polymers was found to enhance its conductivity (σ) and, dielectric permittivity (ϵ) along with biocompatibility. In this paper, human cord blood derived mesenchymal stem cells (CB-hMSCs) were differentiated to skeletal muscle cells (hSkMCs) on spin coated thin GO sheets composed of GOnPs and on electrospun fibrous meshes of GO-PCL (poly-caprolactone) composite. Both substrates exhibited excellent myoblast differentiations and promoted self-alignedmyotubesformation similar to natural orientation. σ, ϵ, microstructural and vibration spectroscopic studies were carried out for the characterizations of GO sheet and the composite scaffolds. Significantly enhanced values of both σ and ϵ of the GO-PCL composite were considered to provide favourable cues for the formation of superior multinucleated myotubes on the electrospun meshes compared to those on thin GO sheets. The present results demonstrated that both substrates might be used as potential candidates for CB-hMSCs differentiation and proliferation for human skeletal muscle tissue regeneration.
TL;DR: The effect of platinum loading and methanol-water ratio on the photocatalytic activity of the faceted TiO2 nanocrystals are investigated and it is found that hydrogen evolution rates have been enhanced significantly upon Pt loading.
Abstract: We report a non-trivial facile chemical approach using ionic liquid ([bmim][Cl]) as a porogen for the synthesis of (001) faceted TiO2 nanocrystals having mesoscopic void space. This faceted TiO2 nanomaterial has been doped with Pt nanoclusters through chemical impregnation. The resulting Pt-doped TiO2 nanomaterials are thoroughly characterized by powder X-ray diffraction (PXRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), ultra high resolution transmission electron microscopy (UHR-TEM), energy dispersive X-ray spectrometry (EDX), UV-vis diffuse reflection spectroscopy (DRS) and N2 sorption studies. These Pt/TiO2 nanocrystals with (001) exposed facets are employed as efficient and benign catalysts for hydrogen production from pure water and methanol–water systems under one AM 1.5G sunlight illumination. The effect of platinum loading and methanol–water ratio on the photocatalytic activity of the faceted TiO2 nanocrystals are investigated and it is found that hydrogen evolution rates have been enhanced significantly upon Pt loading. Under optimized reaction conditions the highest photocatalytic activity of 11.2 mmol h−1 g−1 has been achieved over ca. 1.0 wt% Pt loaded Pt/TiO2 nanocrystals with (001) exposed facets, which is one of the highest hydrogen evolution rates over the noble metal/TiO2 system reported to date in the literature.
TL;DR: Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide( III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core.
Abstract: Employment of two different pyridyl–pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core Relatively less common semirigid pyridyl–pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl–pyrazol We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions Alternating current (ac) susceptibility measurements of the two dysprosium complexes di
TL;DR: Surface enhanced resonance Raman spectroscopy coupled to dynamic electrochemistry data suggests the formation of a bridging peroxide intermediate during O2-reduction by both complexes under steady state reaction conditions, indicating that O-O bond heterolysis is likely to be the rate-determining step at the mass transfer limited region.
Abstract: A synthetic heme-Cu CcO model complex shows selective and highly efficient electrocatalytic 4e(-)/4H(+) O2-reduction to H2O with a large catalytic rate (>10(5) M(-1) s(-1)). While the heme-Cu model (FeCu) shows almost exclusive 4e(-)/4H(+) reduction of O2 to H2O (detected using ring disk electrochemistry and rotating ring disk electrochemistry), when imidazole is bound to the heme (Fe(Im)Cu), this same selective O2-reduction to water occurs only under slow electron fluxes. Surface enhanced resonance Raman spectroscopy coupled to dynamic electrochemistry data suggests the formation of a bridging peroxide intermediate during O2-reduction by both complexes under steady state reaction conditions, indicating that O-O bond heterolysis is likely to be the rate-determining step (RDS) at the mass transfer limited region. The O-O vibrational frequencies at 819 cm(-1) in (16)O2 (759 cm(-1) in (18)O2) for the FeCu complex and at 847 cm(-1) (786 cm(-1)) for the Fe(Im)Cu complex, indicate the formation of side-on and end-on bridging Fe-peroxo-Cu intermediates, respectively, during O2-reduction in an aqueous environment. These data suggest that side-on bridging peroxide intermediates are involved in fast and selective O2-reduction in these synthetic complexes. The greater amount of H2O2 production by the imidazole bound complex under fast electron transfer is due to 1e(-)/1H(+) O2-reduction by the distal Cu where O2 binding to the water bound low spin Fe(II) complex is inhibited.
TL;DR: In this article, the authors derived effective Einstein's equation on the brane using Gauss-Codazzi equation and solved for different conditions on dark radiation and dark pressure to obtain various spherically symmetric solutions.
Abstract: Introducing \(f(\mathcal {R})\) term in the five-dimensional bulk action we derive effective Einstein’s equation on the brane using Gauss–Codazzi equation. This effective equation is then solved for different conditions on dark radiation and dark pressure to obtain various spherically symmetric solutions. Some of these static spherically symmetric solutions correspond to black hole solutions, with parameters induced from the bulk. Specially, the dark pressure and dark radiation terms (electric part of Weyl curvature) affect the brane spherically symmetric solutions significantly. We have solved for one parameter group of conformal motions where the dark radiation and dark pressure terms are exactly obtained exploiting the corresponding Lie symmetry. Various thermodynamic features of these spherically symmetric space-times are studied, showing existence of second order phase transition. This phenomenon has its origin in the higher curvature term with \(f(\mathcal {R})\) gravity in the bulk.
TL;DR: An electrocatalyst for reducing oxygen to water under ambient conditions is developed using site-directed mutants of myoglobin, where both the distal Cu and the redox-active tyrosine residue present in CcO are modelled.
Abstract: Creating an artificial functional mimic of the mitochondrial enzyme cytochrome c oxidase (CcO) has been a long-term goal of the scientific community as such a mimic will not only add to our fundamental understanding of how CcO works but may also pave the way for efficient electrocatalysts for oxygen reduction in hydrogen/oxygen fuel cells. Here we develop an electrocatalyst for reducing oxygen to water under ambient conditions. We use site-directed mutants of myoglobin, where both the distal Cu and the redox-active tyrosine residue present in CcO are modelled. In situ Raman spectroscopy shows that this catalyst features very fast electron transfer rates, facile oxygen binding and O-O bond lysis. An electron transfer shunt from the electrode circumvents the slow dissociation of a ferric hydroxide species, which slows down native CcO (bovine 500 s(-1)), allowing electrocatalytic oxygen reduction rates of 5,000 s(-1) for these biosynthetic models.
TL;DR: In this paper, it was shown that the behavior exhibited by several quantities that characterise these caloric effects (isothermal entropy change, adiabatic temperature change and refrigerant capacity) can be rationalised in terms of the relative distance between the Curie point of the austenite and the martensitic transition temperature.