An Improved Synthesis of α,β Methylenic Cyclic Ketones

This communication describes a convenient two steps procedure for the preparation of α,β methylenic cyclic ketones from arylmethyl ketones involving a preformed Mannich reagent.     

Rings whose singular ideals are nil

Abstract

It is well known that when a ring R satisfies ACC on right annihilators of elements, then the right singular ideal of R is nil, in this case, we say R is right nil-singular. Many classes of rings whose singular ideals are nil, but do not satisfy the ACC on right annihilators, are presented and the behavior of them is investigated with respect to various constructions, in particular skew polynomial rings and triangular matrix rings. The class of right nil-singular rings contains π-regular rings and is closed under direct sums. Examples are provided to explain and delimit our results.     

On the Semiprimitivity of Skew Polynomial Rings

Let R be a semiprime left Goldie ring with a monomorphism and an α-derivation, then is semiprimitive left Goldie ring.     

A note on rings with McCoy-like properties

According to Nielsen [10 Nielsen, P. P. (2006). Semi-commutativity and the McCoy condition. J. Algebra 298:134–141.[Crossref], [Web of Science ®] , [Google Scholar]], a ring R is called right McCoy if for every nonzero f(x),g(x) in the polynomial ring R[x], f(x)g(x) = 0 implies that there exists a nonzero s in R such that f(x)s = 0. In this work, we state two notes on rings with McCoy-like conditions.     

Swallowing sound detection using hidden markov modeling of recurrence plot features

Automated detection of swallowing sounds in swallowing and breath sound recordings is of importance for monitoring purposes in which the recording durations are long. This paper presents a novel method for swallowing sound detection using hidden Markov modeling of recurrence plot features. Tracheal sound recordings of 15 healthy and nine dysphagic subjects were studied. The multidimensional state space trajectory of each signal was reconstructed using the Taken method of delays. The sequences of three recurrence plot features of the reconstructed trajectories (which have shown discriminating capability between swallowing and breath sounds) were modeled by three hidden Markov models. The Viterbi algorithm was used for swallowing sound detection. The results were validated manually by inspection of the simultaneously recorded airflow signal and spectrogram of the sounds, and also by auditory means. The experimental results suggested that the performance of the proposed method using hidden Markov modeling of recurrence plot features was superior to the previous swallowing sound detection methods.     

Synthesis of 6- and 7-acyl-4H-benzothiazin-3-ones

Synthesis of 6- and 7-substituted benzoxazin-3-ones was already described in the literature by acylation of the corresponding benzoxazin-3-ones or cyclization of the corresponding 4- or 5-acyl-2-aminophenols. This paper describes original synthetic pathways to afford the 6- and 7-acyl products in the benzothiazin-3-one series, respectively, via Stille coupling reaction and by acylation.     

The daily radon dose in body organs caused by drinking milk and water

Milk is considered as the richest nutrition, being used by people. When drinking milk or water the radon gas will transfer from air to them rapidly. Since milk is majorly composed of water, probably radon existence in livestock consumable water could be the main cause of its presence in milk. Different portion of milk changed by radon gamma ray and consumption of radon included water or milk has its effects on the human body. For investigation the effect of radon in water or milk on human organs, this study has been done in two phases with MCNPX software. In the first phase, the dose rate of absorbed gamma ray by different portion of milk which is indoctrinated by 1 Bq/m³ of radon during a day is calculated. Moreover, the effects shown by milk and its components in radon gamma spectrum, which is demonstrator of milk absorption spectrum, are also surveyed. In the second phase as well, according to the human body phantom, the absorbed gamma dose caused by daily consumption of indoctrinated water or milk with 1 Bq/m³ radon is calculated. The production rate of free radicals in milk and its different components are derived according to escape data of MCNPX code.     

Generalized Rickart $ \ast $ -Rings

Siberian Mathematical Journal - As a common generalization of Rickart $ \ast $ -rings and generalized Baer $ \ast $ -rings, we say that a ring  $ R $ with an involution ...     

Polynomial extensions of quasi-Baer rings

Summary For a ring endomorphism &agr; and an &agr;-derivation &dgr;, we introduce &agr;-compatible rings which are a generalization of &agr;-rigid rings, and study on the relationship between the quasi Baerness and p.q.-Baer property of a ring R and those of the polynomial extensions (including formal skew power series, skew Laurent polynomials and skew Laurent series). As a consequence we obtain a generalization of [6], [8] and [16].