Biomedical subjects

S M Durbin

Publications and source records attributed to S M Durbin.

3 recordsLinked to original sources

PubMed2006

Direct observation of defect levels in InN by soft X-ray absorption spectroscopy.

We have used synchrotron-based near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the electronic structure of nitrogen-related defects in InN(0001). Several defect levels within the band gap or the conduction band of InN were clearly resolved in NEXAFS spectra around the nitrogen K-edge. We attribute the level observed at 0.3 eV below the conduction band minimum (CBM) to interstitial nitrogen, the level at 1.7 eV above the CBM to antisite nitrogen, and a sharp resonance at 3.2 eV above the CBM to molecular nitrogen, in full agreement with theoretical simulations.

Letter↗

PubMed2001

Long-range reactive dynamics in myoglobin.

We report the complete vibrational spectrum of the probe nucleus 57Fe at the oxygen-binding site of the protein myoglobin. The Fe-pyrrole nitrogen stretching modes of the heme group, identified here, probe asymmetric interactions with the protein environment. Collective oscillations of the polypeptide, rather than localized heme vibrations, dominate the low frequency region. We conclude that the heme "doming" mode is significantly delocalized, so that distant sites respond to oxygen binding on vibrational time scales. This has ramifications for understanding long-range interactions in biomolecules, such as those that mediate cooperativity in allosteric proteins.

Animals↗

PubMed1998

Glomerular filtration rate determination in diabetic patients using iohexol clearance--comparison of single and multiple plasma sampling methods.

Use of iohexol clearance has been described as the gold standard for the measurement of glomerular filtration rate (GFR). It is suggested that multiple plasma sampling following iohexol injection is required to accurately determine GFR by area under plasma clearance curve. The aim of this study was to determine whether single plasma sampling 4 h after injection of iohexol could accurately determine GFR in diabetic patients with mild to moderate renal failure, compared to multiple plasma sampling. A total of 120 GFR determinations in 36 patients with non-insulin dependent diabetic renal disease were done over 1 year. No acute deterioration was seen in renal function following injection of contrast in any patient. Strong correlation in GFR measurement was observed between the multiple plasma sampling method and the single plasma sampling method (r2 = 0.975). Single plasma sampling 4 h after bolus injection of iohexol is a safe and accurate method of determining GFR and change in GFR in diabetic subjects with mild to moderate renal impairment.

Diabetes Mellitus, Type 2↗