α,β-Unsaturated γ-Oxo Carboxylic Acids in Heterocylic Synthesis II. Behavior of 4-(5,5-Dioxodibenzothiophen-2-yl)-4-oxo-2-butenoic Acid Towards Carbon Nucleophiles under Michael Reaction Condition

4-(5,5-Dioxodibenzothiophen-2-yl)-4-oxo-2-butenoic acid ( 1 ) was condensed with compounds containing active methylene groups under Michael reaction conditions to form the Michael adducts 2a-c , 3a-c , and 4a-b . The behavior of Michael adduct towards the action of hydrazine hydrate was investigated. The compounds were tested for biological properties.     

SYNTHESIS OF MONO-AND DIALKYLPHOSPHATES BY THE REACTIONS OF HYDROXYCOMPOUNDS WITH THE PHOSPHORUS PENTAOXIDE UNDER MICROWAVE IRRADIATION

The reactions of phosphorus pentoxide with two alcohols and one phenol were performed in different conditions under microwave irradiation. The products (alkylphosphates and dialkylphosphates) were identical to those formed by classic heating and were obtained with better yields. The speed of the reaction was increased by a factor from 100 to 4000.     

Investigation of 7-((dioctylamino)methyl)quinoline-8-ol for uptake and removal of uranyl ions

A new 8-hydroxyquinoline derivative extractant was synthesized via the Mannich reaction from a secondary amine. Various analytical techniques (¹H, ¹³C NMR, FTIR, mass spectroscopy) were used to characterize our product. The use of this new extractant for the uptake and removal of uranyl ions in aqueous solution was investigated. Conditions for an effective sorption were optimized with respect to different experimental parameters in batch process. The results showed that the extraction rate increases for solutions with a pH in the range [0.65–1.13]. The total sorption capacity was 105 (mg g^?1) under optimum experimental conditions. The extraction of UO₂ ²⁺ was found to be quantitative (100 %) at initial uranyl concentration less than or equal to 41.59 mg/L. Thermodynamic parameters showed the adsorption of an endothermic process and a spontaneous nature, respectively.     

Suppressing Universal Cathode Crossover in High-Energy Lithium Metal Batteries via a Versatile Interlayer Design**

The universal cathode crossover such as chemical and oxygen has been significantly overlooked in lithium metal batteries using high-energy cathodes which leads to severe capacity degradation and raises serious safety concerns. Herein, a versatile and thin (≈25 μm) interlayer composed of multifunctional active sites was developed to simultaneously regulate the Li deposition process and suppress the cathode crossover. The as-induced dual-gradient solid-electrolyte interphase combined with abundant lithiophilic sites enable stable Li stripping/plating process even under high current density of 10 mA cm⁻². Moreover, X-ray photoelectron spectroscopy and synchrotron X-ray experiments revealed that N-rich framework and CoZn dual active sites can effectively mitigate the undesired cathode crossover, hence significantly minimizing Li corrosion. Therefore, assembled lithium metal cells using various high-energy cathode materials including LiNi_0.7Mn_0.2Co_0.1O₂, Li_1.2Co_0.1Mn_0.55Ni_0.15O₂, and sulfur demonstrate significantly improved cycling stability with high cathode loading.     

Glyphosate–Exonuclease Interactions: Reduced Enzymatic Activity as a Route to Glyphosate Biosensing

N-phosphonomethyle-glycine (glyphosate) is the most widely used pesticide worldwide due to its effectiveness in killing weeds at a moderate cost, bringing significant economic benefits. However, owing to its massive use, glyphosate and its residues contaminate surface waters. On site, fast monitoring of contamination is therefore urgently needed to alert local authorities and raise population awareness. Here the hindrance of the activity of two enzymes, the exonuclease I (Exo I) and the T5 exonuclease (T5 Exo) by glyphosate, is reported. These two enzymes digest oligonucleotides into shorter sequences, down to single nucleotides. The presence of glyphosate in the reaction medium hampers the activity of both enzymes, slowing down enzymatic digestion. It is shown by fluorescence spectroscopy that the inhibition of ExoI enzymatic activity is specific to glyphosate, paving the way for the development of a biosensor to detect this pollutant in drinking water at suitable detection limits, i.e., 0.6 nm .     

Amperometric biosensors for glucose based on carbon paste modified electrodes

The modification of carbon-paste electrodes by incorporation of the enzyme glucose oxidase (GOD) is described. The resulting probes can be operated as amperometric glucose sensors in the presence or absence of a mediator (1,1'-dimethylferrocene) mixed into the paste. Extended linear calibration ranges have been obtained up to 90 and 5OmM glucose respectively. The electrode responses were rapid, reaching steady-state values within 30-40 sec. Advantages of using a GOD-paste formulation are suggested. Plasma glucose assays were correlated with spectrophotometric determinations based on glucose oxidase (y = 1.07x - 0.16, r = 0.973, n = 17).     

Synthesis and biological evaluation of <Superscript>99m</Superscript>Tc labeled aryl piperazine derivatives as cerebral radiotracers

The aim of this study is to develop cerebral radiotracers for central nervous system receptors imaging. The synthesis, characterization and biological evaluation of two aryl piperazine ^99mTc-radiocomplexes based on the piano stool motif [CpM(CO₃)] (Cp = cyclopentadienyl, M = ^99mTc/Re) is reported. The ^99mTc-radiocomplexes were obtained quickly (time < 5 min) with high radiochemical yields. The ^99mTc-radiocomplexes characterized by high performance liquid chromatography comparison with the rhenium surrogates have both a suitable lipophilicity and are able to cross the blood brain barrier with 0.43 ± 0.05 and 1.96 ± 0.06% ID/g of brain uptake, at 10 min post injection.     

Positive Elements and Automatic Continuity of Algebra Morphisms

We use positive elements of Hermitian algebras to give results on automatic continuity of algebra morphisms. Consequences and applications are also given.      

Graph-theoretical methods in general function theoryThéorie des graphes dans la théorie generale des fonctions

Consider two maps f and g from a set E into a set F such that f(x)≠g(x) for every x in E. What is the maximal cardinal of a subset A of E such that the images of the restriction of f and g to A are disjoint? Mekler, Pelletier and Taylor have shown that it is card(E) when the set E is infinite; in the finite case, we have proved that it is greater than or equal to card(E)/4. In this paper, using graph theoretical technics, we find these results as a direct application of a lemma of Erdös. Moreover, we show that if $\text{E=F=}\text{R}$, then there exists a countable partition {E_n}_n?1 of $\text{R}$ such that f(E_n)∩g(E_n)=φ, for every n?1. To cite this article: A. El Sahili, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 859–861.     

The numerical index of the space

We give a partial answer to the problem of computing the numerical index of for .