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Biomedical subjects

R J Nicholas

Publications and source records attributed to R J Nicholas.

4 recordsLinked to original sources
PubMed2006

Inversion appendicectomy.

OBJECTIVES: (i) To emphasise that incidental appendicectomy has indications and, to highlight this indications. (ii) To teach that, even when indicated, this procedure should not convert a clean surgical wound into a clean contaminated or even less optimal wound. (iii) To recommend that if an incidental appendicectomy is to achieve (ii) above, inversion appendicectomy is the better option to choose. (iv) To prove that inversion appendicectomy is fast, easy and achieves a similar result as the more popular excision appendicectomy. PATIENTS AND METHODS: This study was carried out in the paediatric surgical unit of Korle-Bu Teaching Hospital Accra, Ghana - between March 2003 and May 2004. PATIENT SELECTION: Fifteen patients qualified for enrollment into this study. These were (i) Those who had clear cut indications for incidental appendicectomy, and had it done as an inversion appendicectomy. (ii) Cases of incidental appendicectomy. METHODS: Eleven of these cases were done for intussusceptions and four for malrotation. Only wounds that qualified as clean surgical wounds were included in this study. There was no age or sex discrimination. RESULTS: Follow up on these patients did not reveal any complications. CONCLUSION: Incidental appemdicectomy has well-defined indications. When indicated in clean wound, inversion appendicectomy is the procedure of choice.

Appendectomy↗
PubMed2005

Diameter-selective encapsulation of metallocenes in single-walled carbon nanotubes.

Encapsulation of organic molecules in carbon nanotubes has opened a new route for the fabrication of hybrid nanostructures. Here we show that diameter-selective encapsulation of two metallocene compounds bis(cyclopentadienyl) cobalt and bis(ethylcyclopentadienyl) cobalt has been observed in single-walled carbon nanotubes. In particular, bis(cyclopentadienyl) cobalt is observed to fill only nanotubes of one specific diameter. Electron transfer from the cobalt ions to the nanotubes has been directly observed through a change in the charge state of the encapsulated molecules. The filling of the tubes is found to induce a red-shift of the photoluminescence emission, which is attributed to the formation of localized impurity states below the conduction band of the nanotubes.

Coated Materials, Biocompatible↗
PubMed2004

Chirality assignment of single-walled carbon nanotubes with strain.

Strain-induced band gap shifts that depend strongly on the chiral angle have been observed by optical spectroscopy in single-walled carbon nanotubes (SWCNTs). Uniaxial and torsional strains are generated by changing the environment surrounding the SWCNTs, using the surrounding D2O ice temperature or the hydration state of a wrapping polymer. These methods are used as diagnostic tools to determine the quantum number q and examine chiral vector indices for specific nanotubes.

Journal Article↗