Two new chalcones from Shuteria sinensis

Two new chalcones, 2′,3,4,4′-tetrahydroxy-2-prenylchalcone (1) and 3-methoxy-2′,4,4′-trihydroxy-2-prenylchalcone (2), together with two known compounds, munsericin (3) and 3,4-dihydroxylonchocarpin (4), were isolated from the ethanol extract of the whole plant of Shuteria sinensis. Their structures were identified by spectroscopic analysis methods, such as 1D and 2D NMR, along with HR-MS data. Glucose metabolism activity of four compounds was tested, compounds 3 and 4 showed effect on the glucose consumption of insulin-resistant HepG2 cells.     

Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography

Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography.     

An Efficient Synthesis of 2‐Substituted Benzoxazoles via RuCl3·3H2O Catalyzed Tandem Reactions in Ionic Liquid

An efficient synthesis of 2‐substituted benzoxazoles through RuCl₃·3H₂O catalyzed, air oxidized tandem reactions of 2‐aminophenols and aldehydes in [bmim]BF₄ was developed. This synthetic strategy has such advantages as mild reaction conditions, cost‐free oxidant, readily available starting materials, and recyclable catalyst and solvent. As an application, it was successfully used in the synthesis of the unreported 5‐(benzoxazol‐2‐yl)‐2′‐deoxyuridines with potential biological activities.     

Direct synthesis of chiral tertiary diphosphines via Pd(II)-catalyzed asymmetric hydrophosphination of dienones

A highly diastereo- and enantioselective Pd(II)-catalyzed hydrophosphination of dienones with Ph(2)PH involving formation of double C*-P bonds has been developed, providing a series of chiral tertiary diphosphines (chiral PCP pincer ligands) in high yields. A catalytic cycle for the reaction was proposed.     

Tandem reactions leading to bicyclic pyrimidine nucleosides and benzopyran-4-ones

A novel, rapid, and efficient synthesis of bicyclic pyrimidine nucleosides and benzopyran-4-ones through oxidation of homopropargyl alcohols and subsequent isomerization, intramolecular addition of enol to allenic ketone has been developed. This methodology provides an efficient and promising approach to the structurally and pharmaceutically interesting pyrano[2,3-d]pyrimidine-2,5-dione nucleoside and benzopyran-4-one derivatives.     

A statistical-weight interpretation for the 1N2 convergence factors of the topological expansion

In a world with exact SU_N symmetry Veneziano has proposed a topological expansion in terms of the small dimensionless parameter $\text{1}\text{N}{}^2$. We relate this convergence factor to the density of hadronic states. The weakness of higher-order corrections (i.e., $\text{1}\text{N}{}^2$) is interpreted as reflecting the small proportion of states that can flow through a “cylinder.” States that communicate with the cylinder may be strongly affected thereby, but the number of such states is relatively small.     

Three-space from quantum mechanics

We formulate a discrete quantum-mechanical precursor to spacetime geometry. The objective is to provide the foundation for a quantum mechanics that is rooted exclusively in quantum-mechanical concepts, with all classical features, including the three-dimensional spatial continuum, emerging dynamically.