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N Browning

Publications and source records attributed to N Browning.

6 recordsLinked to original sources
PubMed2005

Distortion and segregation in a dislocation core region at atomic resolution.

The structure of an isolated, Ga terminated, 30 degree partial dislocation in GaAs:Be is determined by high resolution transmission electron microscopes and focal series reconstruction. The positions of atomic columns in the core region are measured to an accuracy of better than 10 pm. A quantitative comparison of the structure predicted by an ab initio electronic structure total energy calculation to the experiment indicates that theory and experiment agree to within 20 pm. Further analysis shows the deviations between theory and experiment appear to be systematic. Electron energy loss spectroscopy establishes that defects segregate to the core region, thus accounting for the systematic deviations.

Journal Article↗
PubMed2005

Differential expression of a putative riboflavin-aldehyde-forming enzyme (raf) gene during development and post-harvest storage and in different tissue of the sporophore in Agaricus bisporus.

Cloning and characterisation of a putative riboflavin-aldehyde-forming enzyme gene (raf) from the cultivated mushroom Agaricus bisporus and its expression during morphogenesis are described. Three cDNA clones were isolated following differential screening of cDNA libraries from rapidly expanding sporophores and post-harvest stored sporophores. The cDNA sequence and predicted translation analysis revealed an open reading frame (ORF) of 348 nucleotides encoding a polypeptide of 115 amino acids, with three introns (56-66 bases) interrupting the genomic ORF. Blast X searches of the databases with the gene sequence showed homology (40% identity and 56% similarity) to the riboflavin-aldehyde-forming enzyme gene from Schizophyllum commune. In A.bisporus, the raf gene sequence upstream of the ORF contained a large CT-rich putative regulatory element (-64 to -24 bases) found in highly expressed genes in various mushrooms, and a 6-base motif present in the 3' end of the genomic sequence, but not in the corresponding 3' non-coding part of the cDNA, was identified. The raf gene transcripts increased abundantly in rapidly developing sporophores as well in post-harvest stored sporophores. Differential expression of the raf gene transcripts in different tissues of the sporophore was also observed, with higher levels in the stipe compared with the cap and gills. The temporal and spatial expression patterns observed suggest transcriptional regulation of the raf gene during A. bisporus morphogenesis.

Agaricus↗
PubMed2000

Use of arm veins for lower extremity arterial bypass--results, anatomical features and technical considerations.

Forty lower limb bypasses using arm veins were performed on 37 patients. The indications for surgery were limb threat in 50% of cases, graft failure in 33%, aneurysms in 10% and claudication in 7%. Saphenous veins were absent because of prior use in 73% of cases, and because they were unsuitable in 27%. A single vein was used in 48%, 2 veins in 40% and 3 veins in 12% of cases. Seventy-four per cent of cases had a single-vessel run-off below the distal anastomosis. Eighty-two per cent of the distal anastomoses were to infrapopliteal arteries. The primary and secondary rates of these 40 bypasses at a mean follow-up of 14 months (range 1-40 months) were 74% and 90%, respectively. Limb salvage was 94%. Peri-operative morbidity and mortality were 23% and 3%, respectively. The anatomical and technical aspects of harvesting arm veins are critical to the success of this procedure and will be emphasised. We have found arm veins to be a durable source of accessible autogenous grafts for lower limb revascularisation in the absence of suitable saphenous veins.

Aged↗
PubMed1994

Late complications after aortic surgery.

The incidence of false aneurysms, anastomotic stenoses, and ureteric obstruction is reported to be low in patients who have undergone aortic surgery. The use of intravenous peripheral digital subtraction angiography (IVDSA) with completion excretory urography (CEU) may provide a more sensitive means of long-term detection of these complications. The aim of this study was to (1) establish the incidence of anastomotic aneurysms, anastomotic stenoses, and ureteric obstruction after aortic surgery; (2) identify local and systemic factors that predispose to these complications; and (3) evaluate IVDSA as a single radiologic investigation to diagnose these complications. Forty-four patients who had undergone aortic surgery 1 to 12.3 years previously agreed to undergo IVDSA and CEU. False aneurysms were found at 10 distal anastomoses (none at the aorta), for an anastomotic incidence of 11.2% and a patient incidence of 15.9%. Endarterectomy and the femoral artery as a site of distal anastomosis were important factors in the development of anastomotic aneurysms, as were detected radiologically at eight aortic anastomosis (18%). There were no distal anastomotic stenoses. Hypercholesterolemia was more common in this group (62.5%) than in the overall group (21.2%). Three asymptomatic ureteric obstructions were diagnosed in two patients, both of whom had emergency surgery for ruptured aortic aneurysms. The higher incidence of anastomotic aneurysms, anastomotic stenoses, and asymptomatic ureteric obstruction sound merits careful follow-up. IVDSA with CEU may be a simple and effective method of detection.

Anastomosis, Surgical↗