Testing nonlocality of single photons using cavities

A scheme is formulated for testing nonlocality of single photons by considering the state of a single photon that could be located within one of two spatially separated cavities. The outcomes of four experiments on this state involving the resonant interactions of two-level atoms with these cavities and a couple of other auxiliary ones is shown to lead to a contradiction with the criterion of locality.     

Organic–Inorganic Hybrid Supermicroporous Iron(III) Phosphonate Nanoparticles as an Efficient Catalyst for the Synthesis of Biofuels

Here we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP‐1‐3, HFeP‐1‐2, and HFeP‐1‐4) with different Fe^III‐to‐organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene‐1,3,5‐triphosphonic acid and iron(III) chloride under acidic conditions (pH≈4.0). Powder X‐ray diffraction, N₂ sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA‐DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P$\bar 1$ (2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP‐1‐3 by using the MAUD program. The unit cell parameters are a=8.749(1), b=8.578(1), c=17.725(3) Å; α=104.47(3), β=97.64(1), γ=113.56(3)°; and V=1013.41 ų. With these crystal parameters, we proposed an 24‐membered‐ring open framework structure for HFeP‐1. Compound HFeP‐1‐3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer–Emmett–Telller (BET) surface area of 556 m²g^?1 and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions.     

Head group specificity of novel functionalized surfactants: synthesis,self-assembly and calcium tolerance

The present work describes the synthesis, characterization and application of functionalized surfactants derived through simple organic reaction steps. These surfactants have been particularly tailor made to resist hardness due to calcium ions in water. It is unique of its kind because here the surfactants have an analogous hydrophobic chain but differ structurally in the composition of the head groups in terms of the position of attachment of the chain. The effect of this small variability in the head group on the surfactant property, adsorption, self assembly and calcium tolerance behaviour has been studied in detail. This kind of phenol–keto surfactants has not been reported before. It was also found that one of the surfactants was more tolerant towards Ca²⁺ ion than the other. The individual packing behaviour of the surfactants at the air–water interface has been projected to cause this difference which is very interesting.     

Fast-atom bombardment and tandem mass spectrometry of macrolide antibiotics

Molecular weights of macrolide antibiotics can be determined from either (M + H)⁺ or (M + Met)⁺, the latter desorbed from alkali metal salt-saturated matrices. The ion chemistry of macrolides, as determined by tandem mass spectrometry (MS/MS), is different for ions produced as metallated than those formed as (M + H)⁺ species. An explanation for these differences is the location of the charge. For protonated species, the charge is most likely situated on a functional group with high proton affinity, such as the dimethylamino group of the ammo sugar. The alkali metal ion, however, is bonded to the highly oxygenated aglycone. As a result, the collision-activated dissociation spectra of protonated macrolides are simple with readily identifiable fragment ions in both the high and low mass regions but no fragments in the middle mass range. In contrast, the cationized species give complex spectra with many abundant ions, most of which are located in the high mass range. The complementary nature of the fragmentation of these two species recommends the study of both by MS/MS when determining the structure or confirming the identity of these biomaterials.     

A simple synthesis of 4-substituted 2,3-benzoxazinones from C-2 arylated 1,3-indanediones

A simple one-pot procedure for the conversion of 2-hydroxy-2-(2′-hydroxy-aryl)-1,3-indanediones to 4-substituted benzoxazinones has been developed. The process constitutes an interesting acid-catalyzed rearrangement followed by condensation with hydroxylamine.     

Transient waves generated by a moving oscillatory pressure on a sloping beach

A uniform asymptotic analysis of the unsteady wave motion generated by a moving oscillatory pressure distribution on a sloping beach of slope angle /4 is given. Our method of investigation gives important information regarding the nature, number and distribution of the resulting wave pattern. The effect of the sloping beach on the waves is exhibited.     

Capillary-gravity waves produced by a moving pressure distribution

Summary The initial-value problem of surface waves generated by a moving oscillatory pressure distribution is considered and the effect of surface tension on such waves is studied in detail. It is found that the surface tension modifies the critical case in a remarkable way. And also it introduces two extra waves that exist in the upstream side of the pressure distribution.

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Zusammenfassung Das Anfangswertproblem der Oberflächenwellen die durch eine bewegte oszillierende Druckverteilung erzeugt werden, wird behandelt und der Einfluss der Oberflächenspannung wird ausführlich untersucht. Es wird gefunden, dass die Oberflächenspannung den kritischen Fall in bemerkenswerter Weise beeinflusst, und auch zwei besondere Wellen stromaufwärts von der Druckstörung verursacht.

     

beta-Sheet mediated self-assembly of dipeptides of omega-amino acids and remarkable fibrillation in the solid state

Single crystal X-ray diffraction studies show that the extended structure of dipeptide Boc-beta-Ala-m-ABA-OMe (m-ABA: meta-aminobenzoic acid) self-assembles in the solid state by intermolecular hydrogen bonding to create an infinite parallel beta-sheet structure. In dipeptide Boc-gamma-Abu-m-ABA-OMe (gamma-Abu: gamma-aminobutyric acid), two such parallel beta-sheets are further cross-linked by intermolecular hydrogen bonding through m-aminobenzoic acid moieties. SEM (scanning electron microscopy) studies reveal that both the peptides and form amyloid-like fibrils in the solid state. The fibrils are also found to be stained readily by Congo red, a characteristic feature of the amyloid fiber whose accumulation causes several fatal diseases such as Alzheimer's, prion-protein etc.     

Fluorescence quenching of 3,7-diamino-2,8-dimethyl-5-phenyl phenazinium chloride by AgCl and Ag nanoparticles

Quenching of fluorescence of the dye 3,7-diamino-2,8-dimethyl-5-phenyl Phenazinium Chloride (Safranine T) has been investigated by AgCl nanoparticles in the W/O microemulsion medium at different [H₂O]/[AOT] ratios (ω) and with Ag nanoparticles and Ag⁺ in aqueous medium. A simple straightforward method has been introduced to prepare AgCl nanoparticles in well-characterized, monodispersed biomimicking nanocavities formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in heptane. Experimental results reveal that the size of the AgCl nanoparticles increases with increase in hydration. The results of the quenching experiment were analysed in the light of Stern Volmer equation. Quenching of fluorescence of the dye has been found to decrease with decrease in the size of the nanoparticles of AgCl and the variation of Stern Volmer quenching constants (K_SV) with particle size is different for two different size regimes.     

Kinetics and mechanism of reactions of bis(biguanide)copper(II) ion with 2,2′-bipyridyl and 1,10-phenanthroline in aqueous solution

Summary In aqueous solution [Cu(bigH)₂]²⁺ (bigH=biguanide) reacts with 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen) through intermediate formation of ternary complexes [Cu(bigH)(L)]²⁺ and [Cu(bipy)(phen)]²⁺ and binary complexes [CuL₂]²⁺ (L=bipy, phen). The rates of the different steps have been followed in borax buffer (pH 8.0±0.1) by stopped-flow spectrophotometry. For each step k_obs=k₀+k_L[L] and the k_L path appears to be associative. H and S values for the k_L path conform to an isokinetic trend.