717 research outputs found
Potassium Iodide-Functionalized Polyaniline Nanothin Film Chemiresistor for Ultrasensitive Ozone Gas Sensing.
Polyaniline (PANI) nanostructures have been widely studied for their sensitivity to atmospheric pollutants at ambient conditions. We recently showed an effective way to electropolymerize a PANI nanothin film on prefabricated microelectrodes, and demonstrated its remarkable sensing performance to be comparable to that of a one-dimensional nanostructure, such as PANI nanowires. In this work, we report further progress in the application of the PANI nanothin film chemiresistive sensor for the detection of ozone (O₃) by modifying the film with potassium iodide (KI). The KI-PANI sensor exhibited an excellent sensitivity to O₃ (8⁻180 ppb O₃ concentration rage) with a limit of detection of 230 ppt O₃, and exquisite selectivity against active chemicals such as nitrogen dioxide (NO₂) and sulfur dioxide (SO₂). The sensing mechanism of the sensor relied on iodometric chemistry of KI and O₃, producing triiodide ( I 3 - ) that partially doped and increased electrical conductivity of the PANI film. The sensitivity and selectivity of the KI-functionalized PANI film demonstrates the potential use for KI-PANI-based O₃ sensing devices in environmental monitoring and occupational safety
Molecular imprinted polymer functionalized carbon nanotube sensors for detection of saccharides
In this work, we report the synthesis and fabrication of an enzyme-free sugar sensor based on molecularly imprinted polymer (MIP) on the surface of single walled carbon nanotubes (SWNTs). Electropolymerization of 3-aminophenylboronic acid (3-APBA) in the presence of 10 M d-fructose and fluoride at neutral pH conditions resulted in the formation of a self-doped, molecularly imprinted conducting polymer (MICP) via the formation of a stable anionic boronic ester complex between poly(aniline boronic acid) and d-fructose. Template removal generated binding sites on the polymer matrix that were complementary to d-fructose both in structure, i.e., shape, size, and positioning of functional groups, thus enabling sensing of d-fructose with enhanced affinity and specificity over non-MIP based sensors. Using carbon nanotubes along with MICPs helped to develop an efficient electrochemical sensor by enhancing analyte recognition and signal generation. These sensors could be regenerated and used multiple times unlike conventional affinity based biosensors which suffer from physical and chemical stability
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Gas Biosensor Arrays Based on Single-Stranded DNA-Functionalized Single-Walled Carbon Nanotubes for the Detection of Volatile Organic Compound Biomarkers Released by Huanglongbing Disease-Infected Citrus Trees.
Volatile organic compounds (VOCs) released by plants are closely associated with plant metabolism and can serve as biomarkers for disease diagnosis. Huanglongbing (HLB), also known as citrus greening or yellow shoot disease, is a lethal threat to the multi-billion-dollar citrus industry. Early detection of HLB is vital for removal of susceptible citrus trees and containment of the disease. Gas sensors are applied to monitor the air quality or toxic gases owing to their low-cost fabrication, smooth operation, and possible miniaturization. Here, we report on the development, characterization, and application of electrical biosensor arrays based on single-walled carbon nanotubes (SWNTs) decorated with single-stranded DNA (ssDNA) for the detection of four VOCs-ethylhexanol, linalool, tetradecene, and phenylacetaldehyde-that serve as secondary biomarkers for detection of infected citrus trees during the asymptomatic stage. SWNTs were noncovalently functionalized with ssDNA using π-π interaction between the nucleotide and sidewall of SWNTs. The resulting ssDNA-SWNT hybrid structure and device properties were investigated using Raman spectroscopy, ultraviolet (UV) spectroscopy, and electrical measurements. To monitor changes in the four VOCs, gas biosensor arrays consisting of bare SWNTs before and after being decorated with different ssDNA were employed to determine the different concentrations of the four VOCs. The data was processed using principal component analysis (PCA) and neural net fitting (NNF)
The influence of individual provider characteristics and attitudes on caesarean section decision-making: a global review
Caesarean section (CS) rates have risen worldwide in the past two decades, particularly in middle and high-income countries. In addition to changing maternal and health system factors, there is growing evidence that provider factors may contribute to rising unnecessary caesareans. The aim of this review was to assess the evidence for the association between individual provider characteristics, attitudes towards CS and decision-making for CS. A search was conducted in May 2018 in PubMed and Web of Science with 23 papers included in our final review. Our results show that higher anxiety scores and more favourable opinions of CS were associated with increased likelihood of performing CS. These findings highlight a need for appropriate interventions to target provider attitudes towards CS to reduce unnecessary procedures
EFFECTIVENESS OF GLUTEAL MUSCLE STRENGTHENING ON FLAT FOOT
Objectives: To compare the effect of gluteal muscle strengthening along with conventional exercises versus conventional exercises alone on flat foot.Method: An experimental study conducted at Physiotherapy Department of Krishna Institute of Medical Sciences, Karad. A total of 52 subjects were equally divided into two groups using convenient sampling with random allocation (Groups A and B). Baseline treatment was given to both groups (intrinsic muscle strengthening). Group A was given intrinsic muscle strengthening alone while Group B was given gluteal muscle strengthening along with intrinsic muscle strengthening.Result: Statistical analysis was performed using paired t-test and unpaired t-test. In pre-intervention there was no statistically significant difference seen with p values for the navicular drop was 0.3563 and for Ink test was 0.7342. While on comparing the post-interventional values, the results between the two groups using paired t-test revealed that there was extremely significant difference seen with p-value for the navicular drop was <0.0001 and for Ink test was <0.0001.Conclusion: From the study, it can be concluded that there was a significant effect of gluteal muscle strengthening on the flat foot
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