Phase-sensitive detection of bragg scattering at 1D optical lattices

We report on the observation of Bragg scattering at 1D atomic lattices. Cold atoms are confined by optical dipole forces at the antinodes of a standing wave generated by the two counterpropagating modes of a laser-driven high-finesse ring cavity. By heterodyning the Bragg-scattered light with a reference beam, we obtain detailed information on phase shifts imparted by the Bragg scattering process. Being deep in the Lamb-Dicke regime, the scattered light is not broadened by the motion of individual atoms.     

Ultra-cold atoms in an optical cavity: two-mode laser locking to the cavity avoiding radiation pressure

The combination of ultra-cold atomic clouds with the light fields of optical cavities provides a powerful model system for the development of new types of laser cooling and for studying cooperative phenomena. These experiments critically depend on the precise tuning of an incident pump laser with respect to a cavity resonance. Here, we present a simple and reliable experimental tuning scheme based on a two-mode laser spectrometer. The scheme uses a first laser for probing higher-order transversal modes of the cavity having an intensity minimum near the cavity’s optical axis, where the atoms are confined by a magnetic trap. In this way the cavity resonance is observed without exposing the atoms to unwanted radiation pressure. A second laser, which is phase locked to the first and tuned close to a fundamental cavity mode, drives the coherent atom-field dynamics. PACS 42.50.Vk; 42.55.-f; 42.60.Lh; 34.50.-s     

Displacement study on a vancomycin-based stationary phase using N-acetyl-D-alanine as a competing agent

The analysis of the binding data of D,L-dansyl amino acids on a vancomycin stationary phase is investigated in relation to the addition of N-acetyl-D-alanine in the mobile phase. This eluent additive acts as a specific competing agent for the aglycone pocket of the immobilized chiral selector. A model taking into account both stereoselective and nonstereoselective interactions between the solutes and the stationary phase is used to fit the experimental data. From the results, the theoretical approach is considered to be adequate to describe the competing agent dependence on solute retention. To the best of our knowledge, this report constitutes the first example of a displacement study on a macrocyclic antibiotic stationary phase. This work shows that dansyl amino acids bind to the active aglycone pocket of the selector and that this interaction is enantioselective. The results also demonstrate that additional enantioselective sites at the vancomycin surface are involved in the chiral discrimination of these solutes.     

THE LOWEST EXCITED TRIPLET STATES OF CODEINE AND MORPHINE AND OF THEIR MOLECULAR SUBUNITS VERATROLE AND GUAIACOL

Abstract— The lowest excited triplet T₁ states of the two alkaloids, morphine and codeine, have been investigated by ODMR and emission spectroscopy. The electronic character of their T₁ states could be determined by comparing the T₁ properties with those of the constituent parts guaiacol and veratrole. The T₁ properties, e.g. phosphorescence spectra, zero-field splitting parameters and triplet sublevel selective decay rates are very similar for the constituent parts and the alkaloids. Thus, in analogy to veratrole and guaiacol, the T₁ state of codeine and morphine is assigned to a ππ* state mainly localized on the benzene ring and the attached alkoxy and hydroxy groups. There is no evidence for a contribution from the other subunits, trialkylamine and unsaturated alcohol, to the T₁ state of codeine and morphine.     

Breakdown of superconductivity in current-carrying indium whiskers

Like whiskers of tin andtin-indium alloys indium whiskers showV-T andV-I characteristics with a large transition width and regular voltage steps. Applied HF-radiation leads to additional steps of zero slope in theV-I characteristics (current steps) at voltages related to the applied frequency by the Josephson relation, supporting the assumption that phase-slip processes at Josephson frequency are related to the appearance of voltage steps in the transition curves without radiation. At temperatures very close to the critical temperatureT _c0 theV-I characteristics beyond the first voltage step show a differential resistance (dV/dI)₁ and a ratioI ₀/I _c which grow with increasing temperature, contrary to tin andtin-indium alloy whiskers (I _c : critical current,I ₀: extrapolated zero voltage intercept). A probable explanation for this observation is, that in indium whiskers very close toT _c0 nonequilibrium quasiparticles relax by branch crossing processes due to inelastic electron phonon scattering or gap anisotropy.     

Sanov’s Theorem for White Noise Distributions and Application to the Gibbs Conditioning Principle

We consider a positive distribution Φ such that Φ defines a probability measure μ=μ _Φ on the dual of some real nuclear Fréchet space. A large deviation principle is proved for the family {μ _n ,n≥1} where μ _n denotes the image measure of the product measure μ _Φ ⁿ under the empirical distribution function L _n . Here the rate function I is defined on the space ℱ′ _θ (N′)₊ and agrees with the relative entropy function  . As an application, we cite the Gibbs conditioning principle which describes the limiting behaviour as n tends to infinity of the law of k tagged particles Y ₁,…,Y _k under the constraint that L _n ^Y belongs to some subset A ₀.      

Hydrothermally synthesized highly efficient binary silver strontium sulfide (AgSrS) for high-performance supercapattery applications

The increasing demand for sustainable energy has diverted researchers’ intentions toward electrochemical storage devices. This research aims to combine supercapacitors’ characteristics with batteries to create high-performance hybrid energy storage devices. The hydrothermal approach is used to synthesize silver sulfide (Ag₂S), strontium sulfide (SrS), and their composite silver strontium sulfide (AgSrS). XRD is used to evaluate the crystallinity, SEM is used to study the surface morphology, and XPS is used to determine the elemental composition of AgSrS. The BET measurements show a higher surface area of 22.23 m²g⁻¹ for AgSrS. The highest achieved specific capacity with AgSrS is 494.5 C g⁻¹ (137.36 mAh-g⁻¹). The best-tuned material, AgSrS, is then used as the anode in a powered hybrid device with activated carbon (A.C.) as the cathode terminal. This device provides an energy of 26.32 Wh-kg⁻¹ at a power of 800 W kg⁻¹. The device was also put through a durability test, which included 5000 consecutive cycles. After 5000 cycles, a columbic efficiency of 82% was achieved, with 96% capacity retention. This research shows that the composite material AgSrS can be utilized commercially for hybrid energy storage devices in the future.

     

Fecal Metabolic Profiling of Breast Cancer Patients during Neoadjuvant Chemotherapy Reveals Potential Biomarkers

Breast cancer (BC) is the most common form of cancer among women worldwide. Despite the huge advancements in its treatment, the exact etiology of breast cancer still remains unresolved. There is an increasing interest in the role of the gut microbiome in modulating the anti-cancer therapeutic response. It seems that alteration of the microbiome-derived metabolome potentially promotes carcinogenesis. Taken together, metabolomics has arisen as a fascinating new omics field to screen promising metabolic biomarkers. In this study, fecal metabolite profiling was performed using NMR spectroscopy, to identify potential biomarker candidates that can predict response to neoadjuvant chemotherapy (NAC) for breast cancer. Metabolic profiles of feces from patients (n = 8) following chemotherapy treatment cycles were studied. Interestingly, amino acids were found to be upregulated, while lactate and fumaric acid were downregulated in patients under the second and third cycles compared with patients before treatment. Furthermore, short-chain fatty acids (SCFAs) were significantly differentiated between the studied groups. These results strongly suggest that chemotherapy treatment plays a key role in modulating the fecal metabolomic profile of BC patients. In conclusion, we demonstrate the feasibility of identifying specific fecal metabolic profiles reflecting biochemical changes that occur during the chemotherapy treatment. These data give an interesting insight that may complement and improve clinical tools for BC monitoring.     

Convenient Synthesis of 1,2-Diamines from β-Chloro Amines: Precursors of New Substituted Piperazin-2-ones

A practical synthesis of 1,2-diamines from β-chloro amines is reported. The reaction proceeds through the intermediacy of an aziridinium ion opening by amines. The conversion of these diamines into polysubstituted piperazinones is also investigated.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Three-dimensional difference extraction between two similar object forms

A technique using direct object coding is described which permits the extraction of object form differences between two suitably illuminated objects in a three-dimensional manner. While contour differences are visualized similarly as by the usual film coding methods, the form deviations in the direction normal to the film plane lead to Moiré fringes. The structured illumination is achievable coherently or incoherently.