A tighter steering criterion using the Robertson–Schrödinger uncertainty relation

We consider quantum steering by non-Gausssian entangled states. The Reid steering criterion based on the Heisenberg uncertainty relation fails to detect steerability for many categories of such states. Here, we derive a tighter steering criterion using the Robertson–Schrödinger uncertainty relation. We show that our steering condition is able to detect steerability of several classes of non-Gaussian states such as entangled eigenstates of the two-dimensional harmonic oscillator, the photon subtracted squeezed vacuum state and the NOON state.     

Nanoparticle decoration with surfactants: Molecular interactions,assembly, and applications

Nanostructures of diverse chemical nature are used as biomarkers, therapeutics, catalysts, and structural reinforcements. The decoration with surfactants has a long history and is essential to introduce specific functions. The definition of surfactants in this review is very broad, following its lexical meaning “surface active agents”, and therefore includes traditional alkyl modifiers, biological ligands, polymers, and other surface active molecules. The review systematically covers covalent and non-covalent interactions of such surfactants with various types of nanomaterials, including metals, oxides, layered materials, and polymers as well as their applications. The major themes are (i) molecular recognition and noncovalent assembly mechanisms of surfactants on the nanoparticle and nanocrystal surfaces, (ii) covalent grafting techniques and multi-step surface modification, (iii) dispersion properties and surface reactions, (iv) the use of surfactants to influence crystal growth, as well as (v) the incorporation of biorecognition and other material-targeting functionality. For the diverse materials classes, similarities and differences in surfactant assembly, function, as well as materials performance in specific applications are described in a comparative way. Major factors that lead to differentiation are the surface energy, surface chemistry and pH sensitivity, as well as the degree of surface regularity and defects in the nanoparticle cores and in the surfactant shell. The review covers a broad range of surface modifications and applications in biological recognition and therapeutics, sensors, nanomaterials for catalysis, energy conversion and storage, the dispersion properties of nanoparticles in structural composites and cement, as well as purification systems and classical detergents. Design principles for surfactants to optimize the performance of specific nanostructures are discussed. The review concludes with challenges and opportunities.     

Size-dependent interaction of gold nanoparticles with transport protein: A spectroscopic study

Gold nanoparticles of different sizes have been synthesized using sodium citrate as a reducing agent for tetrachloroauric (III) acid. The formed gold nanoparticles have been characterized by the UV-visible and transmission electron microscopy (TEM) measurements. The different sized gold nanoparticles have been used to study the interaction with model transport protein, bovine serum albumin (BSA). Experimental results reveal that BSA molecules adsorbed on the metallic surfaces, suffer strong quenching of their fluorescence and the rate of quenching efficiency is different for different particle size. The analysis of the quenching results has been performed in terms of the Stern-Volmer equation. The mechanism of quenching of fluorescence has been explained. The extent of adsorption of BSA on the gold nanoparticles has been estimated.     

Synthesis,characterization and redox properties of mono- and bis-β-diketonate ruthenium complexes

Complexes of the type [RuIII(L)Cl2(PPh3)2] and [RuII(L)2(PPh3)2] (HL=benzoylacetone or acetylacetone) have been synthesized by the reaction of [RuCl2(PPh3)3] with HL under various experimental conditions. The [RuIII(L)Cl2(PPh3)2] complexes are one-electron paramagnetic species and, in solution, they show intense LMCT transitions in the visible region together with weak ligand-field transitions at lower energies. The [RuII(L)2(PPh3)2] complexes are diamagnetic and their solutions show sharp 1H n.m.r. signals and also show intense MLCT transitions in the visible region. In MeCN solution, the [RuIII(L)Cl2(PPh3)2] complexes show a reversible RuIII-RuII reduction near –0.3V and an irreversible RuIII- RuIV oxidation near 1.2 V versus s.c.e. A reversible RuII-RuIII oxidation is displayed by the [RuII(L)2(PPh3)2] complexes in MeCN solution near 0.3 V versus s.c.e. followed by another reversible RuIII-RuIV oxidation near 1.1 V versus s.c.e. The [RuII(L)2(PPh3)2] complexes have been oxidized to the corresponding [RuIII(L)2(PPh3)2]+ analogues and isolated as ClO4– salts in the solid state. The oxidized complexes are one-electron paramagnetic. They are 1:1 electrolytes in solution and show intense LMCT transitions in the visible region along with weak ligand-field transitions at lower energies.     

Solvent free,fast and asymmetric Michael additions of ketones to nitroolefins using chiral pyrrolidine–pyridone conjugate bases as organocatalysts

New chiral organocatalysts are envisaged based on a pyrrolidine–pyridone conjugate and synthesized from commercially available proline employing standard protocols. These catalysts were found to be useful for asymmetric Michael additions of ketones to nitroolefins to afford the desired products in very good yields (up to 98%) with excellent diastereo- and enantioselectivities (>97:3 syn/anti and up to 98% ee) in very short reaction time compared with the existing reports.     

A solution growth technique for the preparation of copper (II) selenide thin films

A solution growth technique has been developed for the deposition of thin films of copper(II) selenide on glass substrate using a copper(II) salt solution, triethanolamine, ammonia, and sodium selenosulfate as the reacting agents. The material has been characterized through X-ray powder photography, optical absorption, and Hall measurements at room temperature. The films are found to be degenerate and p type with a Moss-Burstein shifted direct band gap of 2.14 eV.     

252Cf-plasma desorption and cesium-ion liquid secondary-ion mass spectrometric analysis of recombinant proteins.

The 35 keV Cs+ liquid secondary-ion mass spectrometry (LSIMS) and 252Cf-plasma desorption (PD) mass spectra of recombinant proteins in the 10-25 kDa mass range are compared. Both techniques showed comparable mass accuracy and sensitivity, and in the case of LSIMS, remarkably short analysis time. Analysis by the PD/nitrocellulose method demonstrated slightly higher sensitivity and relatively lower dependence on the salt and buffer content of the protein sample.     

Mass spectrometric mapping of disulfide bonds in recombinant human interleukin-13

Interleukin 13 (IL-13), a member of the a-helical family of cytokines, has approximately 30% primary sequence homology with IL-4 and shares a common receptor component. The biologically active rhIL-13 is monomeric and non-glycosylated, and contains two disulfide bonds as determined by comparative electrospray mass spectrometric (MS) analysis of the protein before and after reduction with dithiothreitol-dithioerythritol. A trypsin-resistant core peptide of rhIL-13 was isolated and analyzed by plasma desorption (PD) MS, identifying a disulfide-linked core peptide. Subsequent digestion of this core peptide by pepsin, followed by PDMS analysis of the resulting cystine-containing peptic fragments, provided rapid determination of the existing disulfide bonds between cysteine residues 28-56 and 44-70. This disulfide arrangement is similar to that observed for the analogous four internal cysteine residues in hIL-4. The conservation of disulfide bond arrangements between hIL-13 and hIL-4, coupled with their alpha-helical structure and sequence homologies, confirms that IL-13 and IL-4 are structural homologues. It is also consistent with their reported similarities in biological function and receptor binding kinetics.     

The chemistry of [Ru(trpy)(Q)X]n+ (trpy = 2,2′2″-terpyridine; Q = the quinolin-8-olate anion; X = Cl-, H2O,MeCN and N-_3; n = 0 and 1)

Reaction of [Ru(trpy)Cl₃] with quinolin-8-ol (HQ) yields [Ru(trpy)(Q)Cl]. Treatment of [Ru(trpy)(Q)Cl] with Ag⁺ in Me₂CO–H₂O (3:1) and MeCN gives [Ru(trpy)- (Q)(H₂O)]⁺ and [Ru(trpy)(Q)(MeCN)]⁺, respectively, which were isolated as their perchlorate salts. A similar reaction in EtOH, in the presence of NaN₃, yields [Ru(trpy)(Q)(N₃)]. All complexes are diamagnetic (low-spin, d⁶, S = 0) and show many intense m.l.c.t. transitions in the visible region. They display a reversible Ru^II-Ru^III oxidation in the -0.13-0.48 V versus s.c.e. range, followed by an irreversible Ru^III-Ru^IV oxidation in the 0.46–1.08V versus s.c.e. range and three trpy-based reductions on the negative side of s.c.e. Chemical oxidation of [Ru^II(trpy)(Q)Cl] by Ce⁴⁺ gives [Ru(trpy)-(Q)Cl]⁺ which shows intense l.m.c.t. transitions in the visible region together with a weak ligand field transition in the lower energy region. The complex is one-electron paramagnetic (low-spin, d⁵, S=1/2) and shows a rhombic e.s.r. spectrum in MeCN–PhMe (1:1) solution at 77K. Chemical oxidation of [Ru(trpy)(Q)-(H₂O)]⁺ results in the formation of a -oxo dimer, [{Ru(trpy)(Q)}₂O]²⁺.