In an evanescent wave biosensor, height modulation leads to a modulation of the scattered and reflected light intensity. We measured a lower scattering and, therefore, a higher reflection for a decreasing ionic strength, which can be explained by an increasing electrostatic force repelling bound particles from the surface. By comparing bonds with troponin, 105 base pair (bp) DNA and 290
bp DNA, we found that the signal Selleck Salubrinal change for an ensemble of bound particles was related to the length of the analyte. Additionally, we observed for individual particles that the thermal fluctuations of scattered light intensity became smaller for decreasing ionic strength and that the average intensity shifted toward lower values, corresponding to larger particle heights. A quantitative model comprising electrostatic repulsion and van der Waals interaction could fit the measured height displacements for four different DNA lengths (105 bp to 590 bp) as analytes.
Height manipulation of bound particle labels thus reflects analyte-specific properties and may lead to biosensors with enhanced specificity. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3466985]“
“Background: Iron deficiency and iron deficiency anemia are common in patients who undergo gastric bypass. The magnitude of change in iron absorption Ruboxistaurin molecular weight is not well known.
Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP)
on iron status and iron absorption at different stages after surgery. We hypothesized that iron absorption would be markedly impaired immediately after surgery and would not improve after such a procedure.
Design: Anthropometric, body-composition, dietary, hematologic, and iron-absorption measures were determined C59 datasheet in 67 severe and morbidly obese women [mean age: 36.9 +/- 9.8 y; weight: 115.1 +/- 15.6 kg, body mass index (BMI: in kg/m(2)); 45.2 +/- 4.7] who underwent RYGBP. The Roux-en-Y loop length was 125-150 cm. Determinations were carried out before and 6, 12, and 18 mo after surgery. Fifty-one individuals completed all 4 evaluations.
Results: The hemoglobin concentration decreased significantly throughout the study (repeated-measures analysis of variance). The percentage of anemic subjects changed from 1.5% at the beginning of the study to 38.8% at 18 mo. The proportion of patients with low serum ferritin increased from 7.5% to 37.3%. The prevalence of iron deficiency anemia was 23.9% at the end of the experimental period. Iron absorption from both a standard diet and from a standard dose of ferrous ascorbate decreased significantly after 6 mo of RYGBP to 32.7% and 40.3% of their initial values, respectively. No further significant modifications were noted.
Conclusion: Iron absorption is markedly reduced after RYGBP with no further modifications, at least until 18 mo after surgery. Am J Clin Nutr 2009;90:527-32.