Expression of a model peptide of a marine mussel adhesive protein in Escherichia coli and characterization of its structural and functional properties

An expression system for a chemically synthesized gene, encoding a model peptide of marine mussel adhesive protein, was constructed in Escherichia coli under regulation of the T7‐promoter. The model peptide consisted of six repeats of the decapeptide AKPSYPPTYK. Although the product was expressed as an inclusion body, we were able to solubilize it successfully, using acetic acid. The higher‐order structure of this model peptide was investigated using CD spectroscopy and NMR spectroscopy. Using the modified enzyme, mushroom tyrosinase, the tyrosine residue was hydroxylated to 3,4‐dihydoxyphenylalanine (Dopa), and the resulting modified peptide was polymerized, solidified, and insolubilized spontaneously. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 729–736, 1999     

Chemoselective synthesis of polyamides containing hydroxyl and amino substituents by direct polycondensation

A convenient method for the synthesis of polyamides containing hydroxyl and amino substituents on the aromatic rings of the backbones was developed. These polymers were prepared readily by the chemoselective polycondensation of dicarboxylic acids with diamines with hydroxyl and amino functional groups via the activating agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐bezoxazolyl)phosphonate. The model reactions were studied in detail to demonstrate the feasibility of chemoselective polycondensation. The direct polycondensation of 5‐hydroxy or 5‐aminoisophthalic acid with 4,4′‐diamino‐4″‐hydroxytriphenylmethane proceeded smoothly under mild conditions and produced the desired polyamides with inherent viscosities up to 0.73 dL · g⁻¹. The polymers obtained were characterized by IR, ¹H NMR, and ¹³C NMR spectroscopies. The polymers were readily soluble in aprotic polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethyl formamide, and dimethyl sulfoxide. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3875–3882, 2000     

Turbulence structure in an annuli with strongly heated inner cylinder

This structure of turbulent flow in an annulus with strong inner cylinder wall heating has been studied in terms of velocity and temperature with wall temperatures up to 707 °C and a Reynolds number of 48,000. With increase in wall heating, the turbulence very close to the wall was suppressed due to an increase in the kinematic viscosity. In the inner region, the intermittent mixing became intensive and the turbulent intensity increased whereas, in the outer region, the turbulence was suppressed since intermittent mixing was no longer effective. The results show that the thermal structure can be considered in terms of a passive scalar for wall temperatures less then around 200 °C, except in the leading region of the heated area. Received: 2 March 1998/Accepted: 2 November 1998     

Free Self-decomposability and Unimodality of the Fuss–Catalan Distributions

Journal of Statistical Physics - We study properties of the Fuss–Catalan distributions $$\mu (p,r)$$, $$p\ge 1$$, $$01$$ there exists $$r_{0}(p)$$, with $$p-1     

2,2′‐Spiro­bi(1,3‐benzodi­thiole)

The X‐ray structure analysis of 2,2′‐spiro­bi(1,3‐benzodi­thiole), C₁₃H₈S₄, has been performed. The mol­ecule has crystallographic twofold rotation symmetry, the axis passing through the spiro‐C atom. The four S atoms are arranged around the spiro‐C atom in two almost orthogonal CS₂ planes. However, because of large bending of the two five‐membered rings, close contact is present between two connected C atoms on the benzo group of each 1,3‐benzodi­thiole ring and one S atom on the other 1,3‐benzodi­thiole ring.     

Output Characteristics of High-Power Continuous Wave Raman Fiber Laser at 1239 nm Using Phosphosilicate Fiber

A high-power singlemode Raman fiber laser (RFL) with maximum output power of 4.11 W and maximum power conversion efficiency of 47.40% at 1239 nm is realized using continuous wave 8.4 W Yb-doped double-clad fiber laser as a pump, 700 m phosphosilicate fiber, and a Raman cavity formed by a pair of fiber Bragg grating mirrors at 1239 nm. The output characteristics of the RFL at 1239 nm for different fiber lengths and output mirror reflectance are reported. Theoretical simulation is done to numerically optimize for fiber length and output coupler reflectivity to obtain maximum first Stokes power.