Can one determine the underlying fermi surface in the superconducting state of strongly correlated systems?

The question of determining the underlying Fermi surface (FS) that is gapped by superconductivity (SC) is of central importance in strongly correlated systems, particularly in view of angle-resolved photoemission experiments. Here we explore various definitions of the FS in the superconducting state using the zero-energy Green's function, the excitation spectrum, and the momentum distribution. We examine (a) d-wave SC in high-Tc cuprates, and (b) the s-wave superfluid in the BCS-Bose-Einstein condensation (BEC) crossover. In each case we show that the various definitions agree, to a large extent, but all of them violate the Luttinger count and do not enclose the total electron density. We discuss the important role of chemical potential renormalization and incoherent spectral weight in this violation.     

Quantum phases in a doped Mott insulator on the Shastry-Sutherland lattice

We propose the projected BCS wave function as the ground state for the doped Mott insulator SrCu2(BO3)2 on the Shastry-Sutherland lattice. At half filling this wave function yields the exact ground state. Adding mobile charge carriers, we find a strong asymmetry between electron and hole doping. Upon electron doping an unusual metal with strong valence bond correlations forms. Hole doped systems are d-wave resonating valence bond superconductors in which superconductivity is strongly enhanced by the emergence of spatially varying plaquette bond order.     

Towards Maintenance‐Free Biosensors for Hundreds of Bind/Release Cycles

A single aptamer bioreceptor layer was formed using a common streptavidin–biotin immobilization strategy and employed for 100–365 bind/release cycles. Chemically induced aptamer unfolding and release of its bound target was accomplished using alkaline solutions with high salt concentrations or deionized (DI) water. The use of DI water scavenged from the ambient atmosphere represents a first step towards maintenance‐free biosensors that do not require the storage of liquid reagents. The aptamer binding affinity was determined by surface plasmon resonance and found to be almost constant over 100–365 bind/release cycles with a variation of less than 5 % relative standard deviation. This reversible operation of biosensors based on immobilized aptamers without storage of liquid reagents introduces a conceptually new perspective in biosensing. Such new biosensing capability will be important for distributed sensor networks, sensors in resource‐limited settings, and wearable sensor applications.     

Assessment of recharge source to springs in upper Beas basin of Kullu region,Himachal Pradesh,India using isotopic signatures

Journal of Radioanalytical and Nuclear Chemistry - Environmental stable and radioisotope data of springs located in Kullu region of Himachal Pradesh are interpreted to identify the recharge source...     

ExcelAutomat 1.3: Fragment analysis based on the distortion/interaction-activation strain model

The distortion/interaction-activation strain model (D/I-ASM), a fragment analysis method, is applied to study the structure–reactivity relationship in reactions. The application of D/I-ASM involves the generation of input files for points along a reaction profile, submission of input files to a quantum software package, processing of parameters from the resulting output files and generation of graphical plots. The ExcelAutomat tool (Laloo et al., J. Comput. Aided Mol. Des. 2017, 31, 667) provides a framework and library in Visual Basic for Application programming language to process such files. New routines were written in ExcelAutomat 1.3 to facilitate processing of files for D/I-ASM. The worksheet “ASM” was included where initial parameters needed can be defined. The routines for D/I-ASM were tested successfully on bimolecular nucleophilic substitution, cycloaddition, and barrierless reactions. The automation of fragment analysis by ExcelAutomat 1.3 is compatible with Microsoft Excel and LibreOffice Calc. The extensible tool processes files from Gaussian and GAMESS-US packages. © 2018 Wiley Periodicals, Inc.     

Polymeric Encapsulates of Essential Oils and Their Constituents: A Review of Preparation Techniques,Characterization, and Sustainable Release Mechanisms

Natural polymer based encapsulation of essential oil (EO) is one of the emerging and challenging area of research in perfumery, cosmetics, flavoring agents, preservatives, therapeutics, etc. The knowledge of formulation techniques and physico-chemical properties of the polymers are the basic requirements for the successful encapsulations of essential oils (EOs). This current review article is focused on a comparative account of various formulation techniques based on their applicability. For the first time, it also reviews various physico-chemical techniques used in the analysis of EO encapsulates to determine their stability, structure, surface morphology, and encapsulation efficiency. Further, the mechanisms involved in the release of EOs from encapsulates, along with various factors affecting their release, have also been discussed.     

An XRD characterization of the thermal degradation of polyacrylonitrile

Thermal degradation of polyacrylonitrile (PAN) has been studied by combined differential thermal analysis, thermogravimetry, and XRD analysis. On the basis of the experimental observations, it has been suggested that the intramolecular polymerization of nitrile groups to a conjugated polyimine structure is initially limited to only the amorphous zone of PAN, which involves little evolution of off-gases. Polymerization of nitrile group in the crystalline zone starts with the melting of crystallites with the evolution of off-gases from the amorphous-crystalline zone interface. ©1995 John Wiley & Sons, Inc.     

Oxomolybdenum(V) complexes of bis-(2-benzimidazolyl) alkanes

Summary Oxomolybdenum(V) complexes of the type (LH₄) [MoOCl₅] (where LH₂ = dimethylene bis-2-benzimidazole or tetramethylene bis-2-benzimidazole), [MoOCl₃(LH₂)] (where LH₂ = tetramethylene bis-2-benzimidazole), [(Mo₂O₄Cl₂-(H₂O)₃)₂(LH₂)] (where LH₂ = dimethylene bis-2-benzimidazole, tetramethylene bis-2-benzimidazole or hexamethylene bis-2-benzimidazole) and [Mo₂O₃Cl₄(LH₂)₂] (where LH₂ = tetramethylene bis-5-nitro-2-benzimidazole) were prepared and characterised. The mononuclear complexes show u.v.-vis. absorptions characteristic of octahedral molybdenum(V). The dinuclear complexes do not absorb in the visible region, possibly due to the presence of an Mo₂O ₄ ^{2 +}} core, which is also indicated by their diamagnetic behaviour. The biological activities of the free ligands and their complexes have been studied.     

Kinetics and mechanism of the oxidation of neutralized α-hydroxy acids by tris(pyridine-2-carboxylato)manganese(III)

The kinetics of oxidation of the neutralized -hydroxy acids: lactic, -hydroxyisobutyric, mandelic, benzilic and atrolactic acids by tris(pyridine-2-carboxylato)manganese(III) have been studied. The reactions were carried out in a Na(pic)-picH [Na(pic) = sodium salt of pyridine-2-carboxylic acid and picH = pyridine-2-carboxylic acid] buffer medium in the 4.89–6.10pH range. The oxidation rate was found to be independent of pH, and rate follows the order: benzilate > mandelate >atrolactate>lactate > -hydroxy isobutyrate. The oxidation products are MeCHO, Me2CO, PhCHO, Ph2CO and PhCOMe for the respective reactions. A mechanism is proposed involving intermediate formation of hepta-coordinated MnIII complexes in a fast step. The complexes then decompose to give free radicals and MnII in the rate determining step. The free radicals subsequently react with another molecule of the MnIII species to give the respective carbonyl compounds in a fast step.