Morita Invariant Properties of Twisted Poisson Manifolds

In this letter, we study some invariants of integrable twisted Poisson manifolds under Morita equivalence. We show that two twisted symplectic manifolds are Morita equivalent if and only if their fundamental groups are isomorphic. Moreover, the first cohomology group of twisted Poisson manifolds is invariant under Morita equivalence. Finally, we prove that if two twisted Poisson manifolds are Morita equivalent, then their representation categories are equivalent.      

The fluorescent reaction product in the determination of aromatic aldehydes with 2,2''-dithiobis(1-amino-naphthalene)

The fluorescent product formed from benzaldehyde or p-hydroxybenzaldehyde with the reagent in the presence of tri-n-butylphosphine, phosphite and sulphite has been characterized by elemental and structural analysis as the corresponding 2-arylnaphtho [1,2-d ] thiazole.     

Total synthesis of nagilactone F,biologically active nor-diterpenoid dilactone isolated from podocarpus nagi

Nagilactone F was synthesized from (+)-podocarpic acid of the established structure. This work constitutes the first total synthesis of the biologically active norditerpenoid dilactones in $\text{Podocarpus}$ plants.     

A short and stereoselective synthesis of the (±) Prelog-Djerassi lactonic acid

Reaction of meso-4-carbomethoxy-2-methylpentanal ($\text{1}$) with crotyltri-n-butyltin at ?78°C in the presence of 1 eq BF₃·OEt₂, followed by the lactonization with BF₃·OEt₂, gave 6-(1-methylallyl)-3,4,5,6-tetrahydro-3,5-dimethyl-2-pyranone ($\text{2a}$) with the correct stereochemistry (erythro, anti-Cram) in 92% yield, which was converted to the title compound ($\text{3}$) in 85% yield upon the ozonolytic cleavage of the double bond.     

Effects of additional Higgses in supersymmetric grand unified theories

We consider modifications of the minimal supersymmetric SU(5) grand unified model. With the additional Higgses 10 +$\text{10}$, the theory may be modified so that the proton decays dominantly via the conventional mode p→e⁺π with the lifetime π_p=(0.04-710)×10³⁰yr, and sin²θ_W=0.222±0.003.     

Rational design of an L-histidine-derived minimal artificial acylase for the kinetic resolution of racemic alcohols

This communication describes the rational design of an l-histidine-derived minimal artificial acylase. Our new artificial acylase, tert-butyldiphenylsilyl ether of N-(2,4,6-triisopropylbenzenesulfonyl)-pi(Me)-l-histidinol, is a simple and small molecule (molecular weight = 660) that contains only one chiral carbon center that originates from natural l-histidine. The kinetic acylation of racemic secondary alcohols induced by this compound showed an S (kfast/kslow) value of up to 93. A reusable polystyrene-bound artificial acylase was also developed to examine its practical usability.     

Development of a method for evaluating drug-likeness and ease of synthesis using a data set in which compounds are assigned scores based on chemists' intuition

The concept of drug-likeness, an important characteristic for any compound in a screening library, is nevertheless difficult to pin down. Based on our belief that this concept is implicit within the collective experience of working chemists, we devised a data set to capture an intuitive human understanding of both this characteristic and ease of synthesis, a second key characteristic. Five chemists assigned a pair of scores to each of 3980 diverse compounds, with the component scores of each pair corresponding to drug-likeness and ease of synthesis, respectively. Using this data set, we devised binary classifiers with an artificial neural network and a support vector machine. These models were found to efficiently eliminate compounds that are not drug-like and/or hard-to-synthesize derivatives, demonstrating the suitability of these models for use as compound acquisition filters.     

Polymer scrambling: macromolecular radical crossover reaction between the main chains of alkoxyamine-based dynamic covalent polymers

A novel polymer hybridization method, "polymer scrambling", was developed on the basis of the macromolecular radical crossover reaction between the main chains of dynamic covalent polymers. The macromolecular crossover reaction was successfully monitored by GPC and NMR measurements. The present methodology is innovative for the preparation of novel polymer hybrid materials at the nanometer scale.     

Simultaneous determination of water-soluble vitamins in a vitamin-enriched drink by an in-capillary enzyme reaction method

The in-capillary enzyme reaction method was used to determine riboflavin phosphate in a vitamin-enriched drink based on its conversion to riboflavin (vitamin B2) with alkaline phosphatase. Simultaneously, three water-soluble vitamins [thiamine nitrate (vitamin B2 mononitrate), pyridoxine hydrochloride (vitamin B6 hydrochloride) and nicotinamide (vitamin PP)] and anhydrous caffeine in the drink were subjected to quantitative analysis. In the system, electrophoretic migration was used to mix zones containing the substrate (riboflavin phosphate) and the enzyme (alkaline phosphatase). The reaction was then allowed to proceed in the presence of a weak electric field and, finally, the product (riboflavin) of enzyme reaction and other water-soluble vitamins migrated under the influence of an applied electric field to the detector. All the active ingredients and the formulation excipients were successfully separated by micellar electrokinetic chromatography with 135 mM sodium dodecyl sulfate. To prevent inhibition of enzyme reaction by the addition of sodium dodecyl sulfate to the reaction zone, sandwich mode injection, in which plugs of sandwich solution without sodium dodecyl sulfate were introduced into the capillary on both sides of the reaction zone, was utilized as a barrier to protect the enzyme reaction from the inhibitor. The relationship between the peak area of the product and the concentration of the substrate was calculated in the in-capillary enzyme reaction method. Excellent linearity was obtained, with correlation coefficients of 0.9999. The established method was validated and demonstrated to be applicable to the determination of the five active ingredients, including riboflavin phosphate, in a commercial vitamin-enriched drink. No interference from the formulation excipients was observed. Good linearities were obtained, with correlation coefficients above 0.999. Recoveries and precisions ranged from 99.3 to 101.8%, and from 0.1 to 2.5% RSD, respectively. Good agreement was obtained between the established method and traditional high-performance liquid chromatographic methods. These results suggest that the in-capillary enzyme reaction method can be used for the simultaneous determination of riboflavin phosphate and other water-soluble vitamins in pharmaceuticals.     

On the dispersion managed soliton

We review various methods used to study the dispersion managed soliton for nonlinear return-to-zero pulse propagation in optical fibers. A numerical averaging method, the guiding center soliton, the variational method both with a simple and with an extended ansatz, as well as the multiscale theory are discussed and numerically compared, allowing us to show their domains of applicability. Their relative merits and demerits are then exposed. (c) 2000 American Institute of Physics.