C-terminal processing of yeast Spt7 occurs in the absence of functional SAGA complex

Background  

Spt7 is an integral component of the multi-subunit SAGA complex that is required for the expression of ~10% of yeast genes. Two forms of Spt7 have been identified, the second of which is truncated at its C-terminus and found in the SAGA-like (SLIK) complex.     

Normalized stresses around an elliptic hole in a finite plate of linear material subjected to large uniform in-plane loading

Stress-concentration factors associated with the large deformations of in-plane loaded plates with elliptic holes are presented in a form with which designers are familiar. An analytic expression to obtain the stress-concentration factor is included.     

A general protocol for the regio high yielding opening of different glycidol derivatives

Differently protected glycidol derivatives (with Bn, TBDPS, TBS and MPM groups) have been tested for regioselective ring opening with vinylmagnesium bromide in order to obtain useful five-carbon functionalised homoallylic alcohols. Careful choice of the reagents and experimental conditions allowed a general access to important chiral synthons for asymmetric synthesis.     

Efficient synthesis of 5-nitro-benzo[b]furans via 2-bromo-4-nitro-phenyl acetates

Acetylation/Sonogashira cross-coupling reaction/cyclization has been carried out in one-pot using a Na₂PdCl₄/2-(di-tert-butylphosphino)-N-phenylindole/CuI system in TMEDA to give 5-nitro-2-substituted benzo[b]furans in excellent yields. We also describe the extension of this method to 4-EWG-2-bromo-phenols obtaining 2,5-disubstituted-benzo[b]furans in good yields.     

Natural stress used to obtain linear elastic and optical properties of a rubber under large strains

The mechanical and optical properties of some rubbers, like the polyurethanes, used in experimental stress analysis are usually represented by highly nonlinear relationships. In this paper, uniaxial and biaxial tensile tests on a polyurethane rubber are described and the results are analyzed introducing the new concept of “natural stress.” It has been found that the natural stress-natural strain relationship is linear up to 100 per cent strain and seems to correspond to an intrinsic property of the material. The isochromatic fringes are also shown to be linear with respect to natural stress and natural strain.     

Novel chiral calix[4]arenes by direct asymmetric epoxidation reaction

We report the first asymmetric synthesis of trans optically active (+) C 2 1,3-bisarylepoxide of calix[4]arene in excellent chemical yield and >99% ee, and its enantiospecific conversion to the corresponding bis-dioxolane.