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Biomedical subjects

J R Dias

Publications and source records attributed to J R Dias.

12 recordsLinked to original sources
PubMed1992

Percutaneous sclerotherapy of varicocele.

Percutaneous sclerotherapy of varicocele was considered in 21 patients with left sided varicocele, 16 of whom had recurrences after left spermatic vein ligation in the past. Percutaneous sclerotherapy was possible in 17 patients (80.9%). There were no serious complications with venography or sclerotherapy, and the recurrence rate was 17.6%. Percutaneous sclerotherapy is therefore a simple, safe and effective treatment of testicular vein insufficiency.

Adolescent↗
PubMed1982

Mass spectral fragmentation of 24,24-diphenyl-23-ene derivatives of cholic acid.

After electron impact in the mass spectrometer, 24,24-diphenyl-23-ene derivatives of cholic acid ejected the 17-sidechain as an ionized 1,1-diphenyl-butadiene derivative, and the 12 alpha-acetoxy group activated this loss. This contrasts markedly with the mass spectrometric fragmentation of typical sterols having unsaturated 17-sidechains that are also devoid of functionality on the C-ring.

Chemical Phenomena↗
PubMed1980

Studies directed toward synthesis of quassinoids VII. Conversion of chenodeoxycholic acid to a delta-lactone quassinoid analog and generation of A-ring diosphenol acetate derivatives of deoxycholic acid.

Chenodeoxycholic acid was converted to a new 5,14-epi-28,30-dinorquassinoid analog. Two isomeric A-ring diosphenol acetate derivatives of deoxycholic acid were synthesized. A 3-oxo-5 beta-steroid was transformed to a 4-acetoxy-3-oxo-delta 4-steroid by treatment with base and oxygen or to a 2-acetoxy-3-oxo-delta 2-steroid by reaction with cupric chloride in refluxing acetic acid followed by acetylation. Ketene extrusion is a characteristic mass spectral fragmentation of these diosphenol acetates.

Chemical Phenomena↗
PubMedDate not supplied

Determining the number of resonance structures in concealed non-Kekuléan benzenoid hydrocarbons.

The number of resonance structures (SC) for previously published concealed non-Kekuléan benzenoid hydrocarbons is determined. Using a simple computer program, analytical expressions for determining SC for various classes of non-Kekuléan (free-radical) benzenoid hydrocarbons are derived, and some properties of concealed non-Kekuléan benzenoid hydrocarbons are studied.

Journal Article↗
PubMedDate not supplied

Further developments in determining the number of resonance structures in benzenoid free radicals: analytical expressions and elementary substructures.

Relationships for counting the number of resonance structures (SC) of benzenoid free radicals are discussed. The structural origin of some of the coefficients to the SC analytical expressions for series of benzenoid free radicals generated by successive attachment of specific aufbau units is determined. It is shown that a proper pruning fragment for the purpose of a priori determination of the coefficient in the highest degree n term of the SC analytical expression belonging to a given radical series has the property of bond fixation when the operation is performed on every member of that series, resulting in all remnant structures having the same SC value.

Journal Article↗
PubMedDate not supplied

[Urological clinical semeiology].

The authors review all symptoms and signs in the urological field, as well as definitions, characteristics and pathological significance according to current knowledge.

Diagnosis, Differential↗