E,Z-5-Aroylmethylene-3-benzyl-4-oxo-2-thioxo-1,3-thiazolidines (3a-c) react with 4-methoxy and 4-chlorophenylnitrile oxides (4a and b) in pyridine solution to afford one or more of the following compounds: Z-3, Z-2,4-dioxo analogues 5 and 3,6-diaryl1,4,2,5-dioxadiazines (6a-b). The interconversion route is discussed and the structures of all of the synthesised compounds are proven by microanaly...

An NMR study of a 1 : 1 mixture of a chiral lithium amide (4a) and n-BuLi shows that depending on the solvent employed (Et2O or THF) a mixed aggregate can form in proportions that are directly related to the ees measured during the enantioselective alkylation of o-tolualdehyde by these same species.

In this paper, we present new infinite families of three and four variable orthogonal designs based on several constructions derived from complementary sequences. The above method leads to the construction of many classes of orthogonal designs. In addition, we obtain new infinite families of weighing matrices constructed by complementary sequences, such as W (144 + 4s, 144) and W (224 + 4s, 196...

A series of persulfated molecular umbrellas have been synthesized from putrescine, spermidine, spermine, lysine, and cholic acid (1a, 2a, 3a, 4a, and 5a) and their anti-HIV and anti-HSV activities determined. Despite it size, the most active of these conjugates (5a) was able to cross phospholipid bilayers made from 1-palmitoyl-2-oleyol-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl...

The purpose of this study was to elucidate a possible association between ectopic first molar eruption causing root resorption on the distal root of the primary maxillary second molar, and ectopic canine eruption causing root resorption on the permanent maxillary incisors. The subjects consisted of 30 patients, 22 females and eight males in the age range 8.3-15.0 years in whom root resorption o...

Background: The most commonly impacted teeth are the third molars, maxillary canines, maxillary central incisors and premolars. Impacted premolars may lead to aesthetic concerns, masticatory inefficiency and oral hygiene difficulties as well as follicle pathology and destruction of adjacent structures, including neighboring teeth, the purpose of this study to shade light on the prevalence of im...

Using a gradient-corrected density functional method, we studied computationally how single impurity atoms affect the structure and the properties of a Ni4 cluster. H and O atoms coordinate at a Ni-Ni bond, inducing small changes to the structure of bare Ni4 which is essentially a tetrahedron. For a C impurity, we found three stable structures at a Ni4 cluster. In the most stable geometry, the ...

Variations of the electronic properties of nickel during the first stages of oxidation were studied by means of the soft x-ray appearance potential spectroscopy (APS). The spectra consist of a superposition of contributions from metallic nickel and from NiO and yield no evidence for a con­ tinuous change of the oxidation state of the Ni atoms. The binding energy of the 2p3/2-electrons in metall...

Previously, we reported that the properties of microsomal 4-methyl sterol demethylase isolated from liver and Morris hepatomas 5i23C and 7777 are grossly similar.The individ ual enzymic steps of this multicomponent system have now been studied, and the rate-determining step has been deter mined and shown to be identical for liver and these hepato mas. The rates of microsomal oxidative attacks o...