Phycoerythrobilin and phycocyanobilin are covalently attached to the apoproteins of phycoerythrins and phycocyanins. One linkage consists of an ester bond between the hydroxy group of a serine residue and the propionate side chain on one of the inner pyrrole rings (probably ring C). The other linkage is a labile thioether bond between a cysteine residue and the two-carbon side chain on pyrrole ...

Aiming at the sealing failure of a water quality monitoring system in low-temperature environment, double rubber O-ring structure was designed, and its performance low temperatures studied. Finite element software ANSYS constructed structure, change process standard temperature installation studied by two-dimensional axisymmetric model. The results show that equivalent strain stress an increasi...

We present two models of coherent quantum switches constructed from a single-electron quantum ring and a double quantum dot, respectively. The systems are driven by picosecond laser pulses obtained using quantum optimal control theory. The optimized pulses generate electron-current flips in the ring (magnetic switch) and electron transport in the double dot (charge switch) in significantly shor...

In the biologically active title compound, C26H26O5, the pyran ring of the chromene unit adopts a half-chair conformation. The C=C double bond of the propenone unit exhibits a trans conformation and the carbonyl group is syn conformation to the double bond. The dihedral angle between the benzene ring and the benzopyran-one moiety is 31.54 (4)°. The mol-ecular structure is stabilized by an intra...

Oxidative cyclization of the pyrrole–imidazole alkaloids oroidin and sventrin in DMSO/TFA (1:1) yields oxazolines via nucleophilic attack of the carbonyl oxygen at the alkenyl double bond. Oxidation takes place in the benzylic position of the imidazole ring. On prolonged reaction times, the oxazoline ring is hydrolyzed yielding the corresponding ester of pyrrole-2-carboxylic acid containing a f...

BACKGROUND Splitting of the lens capsule with a double-ring contour during continuous curvilinear capsulorrhexis has not often been reported. CASE An 86-year-old woman underwent phacoemulsification cataract extraction with intraocular lens implantation in the right eye. Preoperatively, the anterior lens capsule appeared normal. OBSERVATIONS A double-ring sign was observed during capsulorrhe...

in this paper, we investigate various kinds of extensions of twin-good rings. moreover, we prove that every element of an abelian neat ring r is twin-good if and only if r has no factor ring isomorphic to z2  or z3. the main result of [24] states some conditions that any right self-injective ring r is twin-good. we extend this result to any regular baer ring r by proving that every element of a...

A novel ring structure is proposed for double negative NIMs at visible light spectrum with high FOM (e.g. about 11 at a wavelength of 
583 nm) and low loss. Besides the effective medium theory, an equivalent circuit model is also given to explain physically why our novel structure can give double negative behavior with low loss. Adapted from the original ring structure, two other types of struc...

Phototransduction is initiated by the photoisomerization of rhodopsin (Rho) chromophore 11-cis-retinylidene to all-trans-retinylidene. Here, using Rho regenerated with retinal analogs with different ring sizes, which prevent isomerization around the C(11)=C(12) double bond, the activation mechanism of this G-protein-coupled receptor was investigated. We demonstrate that 11-cis-7-ring-Rho does n...