The tree-level string effective action is known to contain quartic Riemann terms with coefficient $\zeta(3)\alpha'^3$. In the case of type II this first $\alpha'$ correction. We use requirement that reduced on a $d$-torus should have an $O(d,d)$ symmetry find B-field couplings up fifth order in fields. answer turns out surprisingly intricate structure.

background and objectives: plants belonging to the genus tilia l. (tiliaceae) are often tall beautiful trees which are considered for various medicinal potentials of their flowers and leaves. the present study was an attempt to investigate the phytochemical constituents of tilia rubra subsp. caucasica leaves from the hyrcanian forests of north of iran. methods: chromatography on silica gel (nor...

this paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (doxos) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. this novel synthetic method has the advantages of high yields, short reaction times, low cost and availabilit...

among the six classes of pro-2-groups of finite and fixed co-classes and trivial schur multiplicator which studied by abdolzadeh and eick in 2009, there are two classes $$s_5=langle a,bmid [b,a^2]=1, a^2=[b,a]^2, (b^2)^{[b,a]}b^2=1rangle$$ and $$s_6=langle a,t,bmid a^2=b^2,[b,a]^2=1, t^a=t^{-1}[b,a], b^t=abarangle$$that have been conjectured to have deficiency zero presentations. in this paper ...

the leukocyte mi gration test (lht) in the prese nce of na t i v e igg, and l l e v amis ole were studi ed in 9 patients su f f e ring from cla s s i c a l r h e umatoid ar.thri t i s be f o r e a nd after treatment with l evamisole . fi f teen heal thy b l o od dono rs we r e s i mi l a r ly l nvestig ated a s cont r o ls . t- l ympho c yte s ub-popu lations (to ta l a nd active) a nd b-c el l...

this study aimed to determine phenolic compounds of artemisia spicigera (family asteraceae) growing in east-azarbaijan province of iran. 20%, 40 % and 60% spe fractions of methanolic extract of a. spicigera, were subjected to reversed phase preparative hplc, with the mobile phase consisted of methanol and water. structural identification of phytochemicals by spectroscopic methods including uv a...

tumors of t h e male u ret h ra are r a re, co m prising <1% of urolo g ic malignancies. this is a re po rt of a 44-ye a r-old man pre s ented with a 4 -month history of gross initi a l h e maturia and d y s u ri a . af t e r exami n ing the pa t ien t , we found a firm mass ex t ending 1 c m within the p roxim a l bulb a r uret h ra and a pathologic report of moderately differen t iated sq u a...

In this paper, we give a complete classification of vacuum branes, i.e., everywhere umbilical time-like hypersurfaces whose extrinsic curvature is a constant multiple of the induced metric, Kμν = σgμν , in D-dimensional static spacetimes with spatial symmetry G(D−2, K), where G(n,K) is the isometry group of an n-dimensional space with constant sectional curvature K. D ≥ 4 is assumed. It is show...

synthesis of some new monocyclic β-lactams containing a quaternary carbon center via a [2+2]cycloaddition reaction is described. the reaction of achiral diphenyl ketene with chiral aldimines derivedfrom chiral 2, 3, 4, 6-tetra-o-acetyl-β-d-galactopyranosylamine, 2, 3, 4, 6-tetra-o-acetyl-β-dglucopyranosylamine and different benzaldehydes resulted in the formation of β-lactams as singlediastereo...