Based
on the signal amplification elements of planar VS2/AuNPs
nanocomposites and CoFe2O4 nanozyme, we herein
developed an electrochemical biosensor for sensitive kanamycin (Kana)
quantification. A ratiometric sensing platform was presented by incorporating
VS2/AuNPs nanocomposites as a support material with excellent
conductivity and high specific surface area, as well as hairpin DNA
(hDNA) with complementary hybridization of biotinylated Kana-aptamer.
In addition, streptavidin-functionalized CoFe2O4 nanozyme with superior peroxidase-like catalytic activity were immobilized
onto the aptasensor, hence the peroxidase-like catalytic reaction
could yield amplified electrochemical signals. With the presence of
Kana, the aptamer-biorecognition resulted in a quantitative decrease
of nanozyme accumulation and an increase of methylene blue response.
Under optimal conditions, the electrochemical signal ratio of the
aptasensor revealed a linear relation along with the logarithmic concentration
of Kana from 1 pM to 1 μM, with the limit of detection reaching
to 0.5 pM. Moreover, this aptasensor exhibited excellent precision,
as well as high repeatability, hence possessing potentials in real
samples and for diverse targets detection by easy replacement of the
matched aptamer.
ObjectivesPulmonary function impairment and chronic respiratory symptoms after tuberculosis are relatively common in low-income and middle-income countries. We aimed to estimate the impact of post-tuberculosis (post-TB) on pulmonary function.MethodsThis large cross-sectional, population-based study included subjects aged 15 years or older with technically acceptable postbronchodilator spirometry measurements. Post-TB was diagnosed on the basis of radiological evidence and/or medical history. Airflow obstruction was defined as a postbronchodilator forced expiratory volume in 1 s/forced vital capacity ratio below the lower limit of normal of Global Lung Function Initiative (GLI) lung function equations. Small airway dysfunction was diagnosed if at least two of the following indicators were less than 65% of predicted: maximal mid-expiratory flow, forced expiratory flow (FEF) 50% or FEF 75%.ResultsIn this population sample (N=8680, mean age: 40.1 years), 610 (7.0% (95% CI 6.5 to 7.6) participants were post-TB. Post-TB subjects had more frequent respiratory symptoms (46.8% vs 28.3%). Among post-TB subjects, 130 (21.3% (95% CI 18.1 to 24.8)) had airflow obstruction; OR of airflow obstruction was significantly associated with post-TB after adjustment for other confounding factors (OR 1.31, 95% CI 1.05 to 1.62). Post-TB was also associated with small airway dysfunction (OR 1.28, 95% CI1.07 to 1.53), which was present in 297 (48.9% (95% CI 33.9 to 53.0)) post-TB subjects.ConclusionsOur findings support existing knowledge that post-TB is positively associated with pulmonary function impairment and make for frequent respiratory symptoms. Post-TB should be considered as a potentially important cause of airflow obstruction and respiratory symptoms in patients originating from countries with a high burden of tuberculosis.
Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment. In the current study, 1-2, 5-6, and 9-10+ year old homing pigeons collected from the Haidian District of Beijing during 2011 were necropsied and concentrations of cadmium, lead, and mercury were measured in liver, lung, and kidney tissue. At necropsy, gray/black discoloration of the margins of the lungs was observed in 98 % of the pigeons. There were no significant differences in metal concentrations as a function of gender. Cadmium concentrations in all tissues and Pb concentrations in the lung tissues were significantly greater in 9-10+ year old pigeons compared to other age groups indicating that Cd and Pb were bioavailable. Mercury concentrations were not significantly different among age groups. Cadmium concentrations in kidney and lung tissues of 9-10+ year old pigeons were similar to or exceeded concentrations of Cd reported in pigeons from another high traffic urban area and most wild avian species from Korea suggesting that Cd in this region of Beijing may be of concern. Homing pigeons provide valuable exposure and bioaccumulation data not readily available from air monitoring alone, thus providing information regarding potential health effects in wildlife and humans in urban areas. As environmental quality standards are implemented in China, homing pigeons will serve as a valuable bio-monitor of the efficacy of these actions.
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