Biomedical subjects

G R Clark

Publications and source records attributed to G R Clark.

At least 19 recordsLinked to original sources

PubMed1990

Crystal and solution structures of the oligonucleotide d(ATGCGCAT)2: a combined X-ray and NMR study.

A combined crystal-structure determination and NMR analysis of the octanucleotide d(ATGCGCAT)2 is reported. The X-ray analysis shows that the structure is A-form duplex in crystal state. The NMR study shows that in solution this sequence is B-type. The conformational results from each technique are presented in detail. The implications of these findings in terms of conformational flexibility and ligand binding are discussed.

Base Sequence↗

PubMed1989

Methyl 2-[4-(2-chloroethyl)-2,3-dihydro-7-nitroquinoxalin-1-yl]benzoate from intramolecular cyclization of a nitroaromatic mustard.

C18H18CIN3O4, Mr = 375.81, orthorhombic, P212121, a = 11.000 (3), b = 8.023 (2), c = 19.316 (5) A, V = 1704.68 A3, Z = 4, Dm = 1.46 (1), Dx = 1.417 g cm-3, Mo Kalpha, lambda = 0.71069 A, mu = 1.82 cm-1, F(000) = 760, T = 293 (1) K, R = 0.051 for 985 [I greater than 2.5 sigma(I)] reflections. X-ray analysis confirms that the nitroaromatic mustard methyl N-(2-[bis(2-chloroethyl)amino]- 5-nitrophenyl)anthranilate undergoes rapid intramolecular cyclization, but the product is the 7-nitro rather than the 6-nitro derivative previously reported [Chambers & Denny (1986).

Antineoplastic Agents↗

PubMed1979

The crystal and molecular structure of the polymeric copper (II) complex of inosine 5'-monophosphate. A comparison with the previously reported zinc analogue.

X-ray analysis of [Cu . (5'-IMP) . H2O] has shown a structure containing polymeric chains of composition [Cu.5'-IMP]n in which the copper atom is directly bound to N(7) of the base and to three oxygen atoms of different phosphate groups. Whereas the coordination geometry in the analogous zinc complex resembles a distorted tetrahedrom, that in the copper complex is a distorted square plane with weak axial interactions.

Chemical Phenomena↗

PubMed1979

A prosthetic aid for a developing blind child.

An experimental ultrasonic sonar for use as a sensory aid with blind children is described. Novel signal processing techniques make the aid relatively simple to construct, yet allow many of its parameters to be changed in the field. In particular, the aid has two features, a variable range code and an automatic level control, which make the device very versatile in a wide variety of environments. The ultrasonic tranducers used in the aid are described in some detail.

Blindness↗

PubMed1978