Building the “Phosphoindigo” Backbone by Oxidative Coupling of Phosphindolin‐3‐ones with Selenium Dioxide

Oxidative coupling of racemic 1‐ethoxy‐1‐oxophosphindolin‐3‐one ( 1 ) and its 5‐CF₃‐derivative 6 with SeO₂ furnishes 1,1′‐diphosphaindigo derivatives 5 and 7 as bis‐phosphinic esters, i. e. as P^V‐compounds. Like indigo and thioindigo, 5 and 7 exist in the E‐configuration; the crude products of 5 and 7 are mixtures of isomers that are trans‐ and cis‐configurated with respect to the relative orientation of the ester groups oat phosphorus. The structure of the centrosymmetric E‐P(R)P′(S) isomer [(E)‐trans‐isomer] of 5 was determined by X‐ray crystallography. Ester cleavage of 5 , followed by addition of triethylamine to bis‐phosphinic acid 9 (the 1,1,1′,1′‐tetroxide of “phosphoindigo”), furnishes the related bis‐triethylammonium salt 10 as a crystalline hydrate that exhibits an extended hydrogen bonding network.     

A Trotter type result for the stochastic porous media equations

This paper proves the continuous dependence with respect to diffusivity of the solutions to stochastic porous media equations with noncoercive monotone diffusivity functions and multiplicative noise.     

Fast matrix multiplication is stable

We perform forward error analysis for a large class of recursive matrix multiplication algorithms in the spirit of Bini and Lotti [Numer. Math. 36:63–72, 1980]. As a consequence of our analysis, we show that the exponent of matrix multiplication (the optimal running time) can be achieved by numerically stable algorithms. We also show that new group-theoretic algorithms proposed in Cohn and Umans [Foundations of Computer Science, 44th Annual IEEE Symposium, pp. 438–449, 2003] and Cohn et al. [Foundations of Computer Science, 46th Annual IEEE Symposium, pp. 379–388, 2005] are all included in the class of algorithms to which our analysis applies, and are therefore numerically stable. We perform detailed error analysis for three specific fast group-theoretic algorithms. J. Demmel acknowledges support of NSF under grants CCF-0444486, ACI-00090127, CNS-0325873 and of DOE under grant DE-FC02-01ER25478. I. Dumitriu acknowledges support of the Miller Institute for Basic Research in Science. R. Kleinberg is supported by an NSF Mathematical Sciences Postdoctoral Research Fellowship     

Compact perturbations of isometries

We give some characterizations of isometries (contractions) which are perturbations with compact operators of a given arbitrary isometry, in terms of certain natural factorizations. As a consequence we obtain general parametric representations of these perturbations.

     

Evaluation of the renal calculi compositions

Thermal analysis and infrared (IR) spectroscopy are modern physical–chemical methods suitable for the investigation of the kidney stones composition. The applications of these methods in our work were anticipated by performing the standard thermal analysis and standard infrared spectra on pure compounds: oxalates, phosphate, carbonate, and uric acid. This work reveals a logical algorithm for correlating the experimental data regarding urolithiasis types and compositions by thermal analysis methods, Fourier Transform Infrared (FT-IR) spectroscopy, and second derivative FT-IR spectra. The limits and performance of each analysis method have been highlighted, and by correlating the results of both methods we have obtained comprehensive information for the identification and/or determination of the main components as well as of organic and/or inert impurities in calculi composition. The data regarding the urinary calculi composition are important for the clinical guideline in the prophilaxy and methaphylaxy of urolithiasis.     

Physico-chemical and thermal characterisation of new Co(II) complexes with pyrazole derivatives

Four new complexes having general formula [CoL₂(acr)₂] (L: 1H-pyrazole (Hpz) (1); 3-methyl-1H-pyrazole (3-Me-Hpz) (2); 4-methyl-1H-pyrazole (4-Me-Hpz) (3); 3,5-dimethyl-1H-pyrazole (Hdmpz) (4); acr: acrylato ion) were synthesised and characterised. The infrared and UV–vis spectral data indicate that these pyrazole derivatives act as unidentate while acrylato ions act as bidentate chelate ligands generating Co(II) complexes with octahedral stereochemistry. TG experiments revealed the nature of complex species as anhydrous and confirmed those compositions. The biological assays revealed a good activity against Bacillus subtilis for all complexes.     

Comparison of different experimental methods for the assessment of the room’s acoustics

The paper presents the acoustics analysis of three different enclosed spaces. These spaces (rooms) have different geometrical shapes and sizes and serve for different purposes. The early decay time, reverberation time, clarity and center time are evaluated with Dirac, WinMLS, Aurora and Caracad software using simple, low-cost equipment. The listed acoustic parameters were determined using linear sine sweep and impulsive sources. Comparisons between experimental measurements, simulations and analytic results were done. The room impulse response measurement proved to be the most reliable method to evaluate the properties of different rooms even if the measurements are perturbed by non-idealities of the low-cost equipment.     

A Cheminformatics Study Regarding the Human Health Risks Assessment of the Stereoisomers of Difenoconazole

Difenoconazole is a chemical entity containing two chiral centers and having four stereoisomers: (2R,4R)-, (2R,4S)-, (2S,4R)- and (2S,4S)-difenoconazole, the marketed product containing a mixture of these isomers. Residues of difenoconazole have been identified in many agricultural products and drinking water. A computational approach has been used to evaluate the toxicological effects of the difenoconazole stereoisomers on humans. It integrates predictions of absorption, distribution, metabolism, excretion and toxicity (ADMET) profiles, prediction of metabolism sites, and assessment of the interactions of the difenoconazole stereoisomers with human cytochromes, nuclear receptors and plasma proteins by molecular docking. Several toxicological effects have been identified for all the difenoconazole stereoisomers: high plasma protein binding, inhibition of cytochromes, possible hepatotoxicity, neurotoxicity, mutagenicity, skin sensitization potential, moderate potential to produce endocrine disrupting effects. There were small differences in the predicted probabilities of producing various biological effects between the distinct stereoisomers of difenoconazole. Furthermore, there were significant differences between the interacting energies of the difenoconazole stereoisomers with plasma proteins and human cytochromes, the spectra of the hydrogen bonds and aromatic donor–acceptor interactions being quite distinct. Some distinguishing results have been obtained for the (2S,4S)-difenoconazole: it registered the highest value for clearance, exposed reasonable probabilities to produce cardiotoxicity and carcinogenicity and negatively affected numerous nuclear receptors.     

Electrochemical sensors based on antimony tin oxide-Prussian blue screen-printed electrode and PEDOT-Prussian blue for potassium ion detection

Journal of Solid State Electrochemistry - The development and analytical applications of electrochemical sensors based on antimony tin oxide (ATO)–Prussian blue (PB) screen-printed electrode...