Controlled coupling of counterpropagating whispering-gallery modes by a single Rayleigh scatterer: a classical problem in a quantum optical light

We present experiments where a single subwavelength scatterer is used to examine and control the backscattering induced coupling between counterpropagating high-Q modes of a microsphere resonator. Our measurements reveal the standing wave character of the resulting symmetric and antisymmetric eigenmodes, their unbalanced intensity distributions, and the coherent nature of their coupling. We discuss our findings and the underlying classical physics in the framework common to quantum optics and provide a particularly intuitive explanation of the central processes.     

Soft landed protein voltammetry

The present work illustrates a new method: soft landed protein voltammetry (SLPV); this experimental procedure is based on the coupling of ion soft landing with a voltammetric technique and allows the electrode surface to be functionalized with biologically active molecules, thus opening up numerous new perspectives ranging from molecular electronics to protein chips.     

Vertical averages in a three-dimensional diffusion of pollutants

Summary ?A horizontal multiple gradient? model for the integration of the diffusion equation as ordinary differential equation in cases with cylindrical symmetry is described. Such a method is applied to the steadystate case of diffusion into the Atlantic Ocean of the saltier Mediterranean water and its very good approximation is pointed out. Finally, the parameters introduced are discussed as far as their physical meaning is concerned.

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Riassunto Si descrive un metodo di sviluppo in serie di gradienti orizzontali della concentrazione per integrare, in casi a simmetria cilindrica, l'equazione di diffusione come equazione differenziale ordinaria. Si applica tale metodo ad un caso stazionario di diffusione di acqua piú salata mediterranea nell'Oceano Atlantico, se ne constata la ottima approsimazione e si discutono i parametri introdotti alla luce della loro plausibilità.

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Резюме Описывается модель ?горизонтального многократного градиента? для интегрирования уравнения диффузии как обыкновенного дифференциального уравнения в случаях с цилиндрической симметрией. Такой метод применяется к стационарному случаю диффузии более соленой воды Средиземного моря в Атлантический океан. В заключение, обсуждаются введенные параметры и их физический смысл.

     

Synthesis of 3-disubstituted 3H-4,1,2-benzothiadiazines and 3-disubstituted 3H-4,1,2-benzothiadiazine 4,4-dioxides

3H-4,1,2-Benzothiadiazines 8 and 9 have been prepared by cyclization of the key intermediates 6 and 7 . The diazotisation of 2-aminophenylthio and 2-aminophenylsulfone derivatives could represent a new convenient synthetic way to obtain 4,1,2-benzothiadiazines.     

The chemistry and the stereochemistry of poly(N-alkyliminoalanes) : VI. A novel synthesis of poly(N-alkyliminoalanes) by reaction of alkali metal alanates with primary amines

A novel synthesis of poly(N-alkyliminoalanes) (PIA) is reported. This involves the reaction in hydrocarbon solvents of LiAlH₄ or NaAlH₄ with primary amines having a nitrogen with α- or β- secondary carbon atoms or with tertbutylamine. Complexes of iminoalanes with alkali metal hydrides are obtained from linear amines. The same reaction carried out in polar solvents always gives complexes of PIA with LiH or NaH and the solvent. This new synthesis is simpler and convenient for producing soluble and well characterized PIA, some of which are not obtainable by other methods.     

Synthesis of 3-substituted 4,1,2-benzothiadiazine 4,4-dioxides and 2 or 3-substituted 1,4-benzothiazine 1,1-dioxides

The title compounds were prepared starting from the synthones 6 using two different synthetic approaches: 3-substituted 1,4-benzothiazine 1,1-dioxides were synthesised by cyclisation with phosphorus oxychloride as the Vilsmeier reagent, while 4,1,2-benzothiadiazine 4,4-dioxides and 3-substituted 1,4-benzothiazine 1,1-dioxides were obtained by direct diazotisation or by cyclisation with triethyl orthoformate.     

Metal ion interaction with ribosomal RNA

Summary We have used UV differential spectroscopy in order to detect small modifications in the ribosomal RNA absorption spectrum due to the binding of rRNA molecules with the metal ions Na⁺, K⁺, Mg²⁺, Ca²⁺, Mn²⁺, Co²⁺ and Ni²⁺. Our data show that all the ions, investigated are involved in ion-type bond with the phosphate groups of rRNA and cause a refolding of the molecules with an overall increase in basebase ?stacking? interactions. Besides this ion-type binding with phosphate groups, transition metal ions Mn²⁺, Co²⁺, and Ni²⁺ are also able to bond directly to the bases To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Rapid screening of beta‐adrenergic agents and related compounds in human urine for anti‐doping purpose using capillary electrophoresis with dynamic coating

This paper presents a capillary electrophoresis method, developed for the detection, in human urine, of beta‐adrenergic agents and phenolalkylamines. The electrophoretic separation is achieved in less than 10 min and is based on the use of CEofix kit, for the dynamic capillary coating. The effects of accelerator buffer pH and separation voltage were investigated. The optimum buffer pH was found to be 2.5 for beta2‐agonists and 6.2 for beta‐blockers and phenoalkylamines with a separation voltage of 15 kV. Urine samples spiked with the compounds here studied were treated according to the standard procedure (SPE and evaporation to dryness) and analyzed by CE interfaced with an UV diode‐array, set at 195 and 210 nm. The quantitative validation results, obtained analyzing samples at three different concentrations, show a good precision of peak areas that do not exceed 5% for intra‐day assays and 10% for inter‐day assays. Good linearity (r² > 0.995) was obtained within the 50–500 ng/mL concentration range. The qualitative validation data show a relative migration times (MTs) variation lower than 1%. The analytes were clearly distinguishable in urine, with LOD and LOQ in the range of 10–80 and 40–100 ng/mL, respectively.     

NMR spectroscopy evaluation of direct relationship between soils and molecular composition of red wines from Aglianico grapes

¹H NMR spectroscopy was employed to investigate the molecular quality of Aglianico red wines from the Campania region of Italy. The wines were obtained from three different Aglianico vineyards characterized by different microclimatic and pedological properties. In order to reach an objective evaluation of “terroir” influence on wine quality, grapes were subjected to the same winemaking procedures. The careful subtraction of water and ethanol signals from NMR spectra allowed to statistically recognize the metabolites to be employed in multivariate statistical methods: Principal Component Analysis (PCA), Discriminant Analysis (DA) and Hierarchical Clustering Analysis (HCA). The three wines were differentiated from each other by six metabolites: α-hydroxyisobutyrate, lactic acid, succinic acid, glycerol, α-fructose and β-d-glucuronic acid. All multivariate analyses confirmed that the differentiation among the wines were related to micro-climate, and carbonate, clay, and organic matter content of soils. Additionally, the wine discrimination ability of NMR spectroscopy combined with chemometric methods, was proved when commercial Aglianico wines, deriving from different soils, were shown to be statistically different from the studied wines. Our findings indicate that multivariate statistical elaboration of NMR spectra of wines is a fast and accurate method to evaluate the molecular quality of wines, underlining the objective relation with terroir.