On Turan hypergraphs

Let α(H) be the stability number of a hypergraph H = (X, $\text{E}$). T(n, k, α) is the smallest q such that there exists a k-uniform hypergraph H with n vertices, q edges and with α(H) ? α. A k-uniform hypergraph H, with n vertices, T(n, k, α) edges and α(H) ?α is a Turan hypergraph. The value of T(n, 2, α) is given by a theorem of Turan. In this paper new lower bounds to T(n, k, α) are obtained and it is proved that an infinity of affine spaces are Turan hypergraphs.     

Naked and Self‐Clickable Propargylic‐Decorated Single‐Chain Nanoparticle Precursors via Redox‐Initiated RAFT Polymerization

Protection of acetylenic monomers is a common practice to avoid parasitic side reactions during polymerization. Herein, we report that redox‐initiated RAFT polymerization allows the direct, room temperature synthesis of a variety of single‐chain nanoparticle precursors (displaying narrow molecular weight dispersity, / = 1.12 –1.37 up to = 100 kDa) containing well‐defined amounts of naked, unprotected acetylenic functional groups available for rapid and quantitative intrachain cross‐linking via metal‐catalyzed carbon–carbon coupling (i.e., C–C “click” chemistry). To illustrate the useful “self‐clickable” character of the new unprotected acetylenic precursors, single‐chain nanoparticles have been prepared for the first time in a facile and highly efficient manner by copper‐catalyzed alkyne homocoupling (i.e., Glaser–Hay coupling) at room temperature under normal air atmosphere.     

Atisideritol,a new ent-atis-13-ene from a sideritis pusilla (Lag) Pau ssp

From Sideritis pusilla subspecia has been isolated an ent-11β, 16α,17-trihydroxy-atis-13-ene diterpenoid, and the trivial name atisideritol is proposed for it.     

Degrees and independent sets of hypergraphs

Lower bounds for the cardinality of maximal and maximum independent sets in hypergraphs are obtained from two different definitions of the degrees of the vertices.     

The 13C NMR spectrum of 5- O-β-D-primeverosyl genkwanine

The ¹³C NMR spectra of 5-O-β-D-primeverosyl genkwanine and its acetate are studied and assignments are proposed.     

Modeling inverse microemulsion polymerization

A mathematical model for inverse microemulsion polymerization has been developed. The model has been used to fit experimental results of the effect of initiator concentration, light intensity, emulsifier concentration, and dispersed phase weight fraction on the monomer conversion evolution, particle size, and polymer molecular weight in the inverse microemulsion polymerization of 2-methacryloyl oxyethyl trimethyl ammonium chloride (MADQUAT) initiated by UV light in the presence of AIBN. A good fitting of the experimental data was achieved. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2167–2178, 1999     

Kinetics of the photoinitiated inverse microemulsion polymerization of 2-methacryloyl oxyethyl trimethyl ammonium chloride

The polymerization of inverse microemulsions of 2-methacryloyl oxyethyl trimethyl ammonium chloride stabilized by a blend of nonionic emulsifiers (a sorbitan sesquioleate and a sorbitan monooleate) and initiated by UV light in the presence of Azobis(isobutyronitrile) (AIBN) was investigated. The effect of initiator concentration, light intensity, emulsifier concentration, and dispersed phase weight fraction on the polymerization rate (R_p), number of polymer particles (N_p), and polymer molecular weight (M_w) was studied. The application of this process to tubular reactors is discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 737–748, 1998