Coherent optical manipulations of the fundamental state in a single quantum dot

By means of an original all-optical experimental technique using microphotoluminescence in a waveguiding geometry, resonant coherent manipulation of quantum states in a single quantum dot becomes possible now. Resonant Rabi oscillation of the fundamental exciton state in a single quantum dot has been realized. We present the results obtained on two different kinds of samples: InAs/GaAs self-assembled quantum dots and naturally formed GaAs quantum dots by thickness fluctuations.     

Identification and Capture of Phenolic Compounds from a Rapeseed Meal Protein Isolate Production Process By-Product by Macroporous Resin and Valorization Their Antioxidant Properties

In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry.     

Monotonically Computable Real Numbers

Area number x is called k‐monotonically computable (k‐mc), for constant k > 0, if there is a computable sequence (x_n)_{n ∈ ℕ} of rational numbers which converges to x such that the convergence is k‐monotonic in the sense that k · |x — x_n| ≥ |x — x_m| for any m > n and x is monotonically computable (mc) if it is k‐mc for some k > 0. x is weakly computable if there is a computable sequence (x_s)_{s ∈ ℕ} of rational numbers converging to x such that the sum $\sum _{s \in \mathbb{N}}$|x_s — x_{s + 1}| is finite. In this paper we show that a mc real numbers are weakly computable but the converse fails. Furthermore, we show also an infinite hierarchy of mc real numbers.     

Anion-π Interaction for Molecular Recognition of Anions: Focus on Cooperativity with Hydrogen Bonding

Anion recognition represents an active area of research in supramolecular chemistry. The last two decades have been marked by spectacular advances in the design of new anion receptors. Moreover, the development of approaches combining experimental and theoretical studies has proved to be particularly relevant, allowing for a better understanding and rationalization of the phenomena involved in anion complexation processes. In this context, the combination of weak interactions within the same receptor and their synergistic effects, called cooperativity, has attracted increasing interest within the scientific community. This Review focuses on the combination of anion-π and hydrogen bonds and the emerging concept of cooperativity. The most relevant anion-π donor families are presented. The concept of cooperativity is illustrated using the most recent examples present in current literature.     

ChemInform Abstract: Two Caesium Vanadium Hydrogenphosphates,with Tunnelled Structures: Cs2V2O3(PO4)(HPO4) and Cs2 [(VO)3(HPO4)4(H2O)] ·H2O.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

2-Nitroimidazole Based PET Tracers: Development of a General Synthetic Approach and Fluorination Methodology

2-Nitroimidazole based PET tracers are widely used for non-invasive hypoxic tumor diagnosis. In this context, we report here a general method based on a central Mitsunobu reaction to easily access 2-nitroimidazole precursors. Optimization of fluorination conditions is described and successfully applied to the radiofluorination of the 2-nitroimidazole precursors. Moreover, the radiosynthesis of a new potential hypoxia PET tracer is also described. Finally, this article presents a SFC analytical method allowing both an easy monitoring of the fluorination reactions and the measurement of partition coefficients (logP).