Spectroscopic,X-ray Diffraction and Density Functional Theory Study of Intra- and Intermolecular Hydrogen Bonds in Ortho-(4-tolylsulfonamido)benzamides

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH₂ single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their ¹H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.     

Identification of novel microsatellite markers <1 Mb from the HBB gene and development of a single‐tube pentadecaplex PCR panel of highly polymorphic markers for preimplantation genetic diagnosis of beta‐thalassemia

Beta (β)‐thalassemia is one of the most common monogenic diseases worldwide. Affected pregnancies can be avoided through preimplantation genetic diagnosis (PGD), which commonly involves customized assays to detect the different combinations of β‐globin (HBB) gene mutations present in couples, in conjunction with linkage analysis of flanking microsatellite markers. Currently, the limited number of reported closely linked markers hampers their utility in indirect linkage‐based PGD for this disorder. To increase the available markers closely flanking the HBB gene, an in silico search was performed to identify all markers within 1 Mb flanking the HBB gene. Fifteen markers with potentially high polymorphism information content (PIC) and heterozygosity values were selected and optimized into a single‐tube pentadecaplex PCR panel. Allele frequencies and polymorphism and heterozygosity indices of each marker were assessed in five populations. A total of 238 alleles were observed from the 15 markers. PIC was >0.7 for all markers, with expected heterozygosity and observed heterozygosity values ranging from 0.74 to 0.90 and 0.72 to 0.88, respectively. Greater than 99% of individuals were heterozygous for at least seven markers, with at least two heterozygous markers on either side of the HBB gene. The pentadecaplex marker assay also performed reliably on single cells either directly or after whole genome amplification, thus validating its use in standalone linkage‐based β‐thalassemia PGD or in conjunction with HBB mutation detection.     

He2@C60: Thoughts of the concept of a molecule and of the concept of a bond in quantum chemistry

We present a broad palette of discussions of the concepts of a molecule and a chemical bond that always lay down behind all computational modeling in quantum chemistry and of the endohedral fullerene He₂@C₆₀ in particular. For this purpose, we offer the definition of quantum chemistry as composed of three ingredients. Each of them is illustrated by its particular concept, either that of a molecule or a bond. The third, computational ingredient is tackled to resolve the bonding manifold of He₂@C₆₀ and to demonstrate that van‐der‐Waals binding of He? He is converted within He₂@C₆₀ into a stronger bond due to that C₆₀ acts as an electronic buffer and [He₂] moiety mimics a fractionally charged . Experimental fingerprints of He₂@C₆₀ are computed. © 2015 Wiley Periodicals, Inc.     

Conformations of cationized linear oligosaccharides revealed by FTMS combined with in‐ESI H/D exchange

Previously (Kostyukevich et al. Anal Chem 2014, 86, 2595), we have reported that oligosaccharides anions are produced in the electrospray in two different conformations, which differ by the rate of gas phase hydrogen/deuterium (H/D) exchange reaction. In the present paper, we apply the in‐electrospray ionization (ESI) source H/D exchange approach for the investigation of the oligosaccharides cations formed by attaching of metal ions (Na, K) to the molecule. It was observed that the formation of different conformers can be manipulated by varying the temperature of the desolvating capillary of the ESI interphase. Separation of the conformers was performed using gas phase H/D approach. Because the conformers have different rates of the H/D exchange reaction, the deuterium distribution spectrum becomes bimodal. It was found that the conformation corresponding to the slow H/D exchange rate dominates in the spectrum when the capillary temperature is low (~200 °C), and the conformation corresponding to the fast H/D exchange rate dominates at high (~400 °C) temperatures. In the intermediate temperature region, two conformers are present simultaneously. It was also observed that large oligosaccharide requires higher temperature for the formation of another conformer. It was found that the presence of the conformers considerably depends on the solvent used for ESI and the pH. We have compared these results with the previously performed in‐ESI source H/D exchange experiments with peptides and proteins. Copyright © 2015 John Wiley & Sons, Ltd.     

Tests of relativity by complementary rotating Michelson-Morley experiments

We report relativity tests based on data from two simultaneous Michelson-Morley experiments, spanning a period of more than 1 yr. Both were actively rotated on turntables. One (in Berlin, Germany) uses optical Fabry-Perot resonators made of fused silica; the other (in Perth, Australia) uses microwave whispering-gallery sapphire resonators. Within the standard model extension, we obtain simultaneous limits on Lorentz violation for electrons (5 coefficients) and photons (8) at levels down to 10(-16), improved by factors between 3 and 50 compared to previous work.     

Discrete X-wave formation in nonlinear waveguide arrays

We present experimental evidence for the spontaneous formation of discrete X waves in AlGaAs waveguide arrays. This new family of optical waves has been excited, for the first time, by using the interplay between discrete diffraction and normal temporal dispersion, in the presence of Kerr nonlinearity. Our experimental results are in good agreement with theoretical predictions.     

Stochastic dynamics of a Josephson junction threshold detector

We generalize the stochastic path integral formalism by considering Hamiltonian dynamics in the presence of general Markovian noise. Kramers' solution of the activation rate for escape over a barrier is generalized for non-Gaussian driving noise in both the overdamped and underdamped limit. We apply our general results to a Josephson junction detector measuring the electron counting statistics of a mesoscopic conductor. The activation rate dependence on the third current cumulant includes an additional term originating from the backaction of the measurement circuit.     

Dielectric microconcentrators for efficiency enhancement in concentrator solar cells

Metal fingers typically cover more than 10% of the active area of concentrator solar cells. Microfabricated dielectric optical designs that can completely eliminate front contact shading losses are explored. Essentially no microconcentrator optical losses need be incurred, series resistance losses can be reduced, and net efficiency gains of roughly 15% (relative) are realistic.     

A Remark on the Essential Spectra of Toeplitz Operators with Bounded Measurable Coefficients

We establish a sufficient condition for a point to belong to the essential spectrum of a Toeplitz operator with a bounded measurable coefficient. This condition uses geometric information on the cluster values of the coefficient.     

Tamm oscillations in semi-infinite nonlinear waveguide arrays

We demonstrate the existence of nonlinear Tamm oscillations at the interface between a substrate and a one-dimensional waveguide array with either cubic or saturable, self-focusing or self-defocusing nonlinearity. Light is trapped in the vicinity of the array boundary due to the interplay between the repulsive edge potential and Bragg reflection inside the array. In the special case when this potential is linear these oscillations reduce themselves to surface Bloch oscillations.