Dual-mode Analysis Research Articles

Efficient and robust dual modes of fluorescence sensing and smartphone readout for the detection of pyrethroids using artificial receptors bound inside a covalent organic framework

In the study, we have developed an efficient and robust method using dual modes of fluorescence sensing and smartphone readout for the detection of pyrethroids using artificial receptors inside a covalent organic framework. Carbazole-conjugated frameworks (CCFs) were used to prepare efficient fluorescent probes that combine stability with light-emitting activity. CN linkages between aldehydes and amines formed Schiff bases, allowing the development of layered structures, creating exceptionally stable frameworks. Artificial receptors that can bind compounds inside the CCFs with high affinity, for both the detection and absorption of λ-cyhalothrin (LC), were constructed using room-temperature reverse microemulsion polymerization. Under optimum conditions, the fluorescence sensing correlation with the concentration of LC showed good linearity in the range of 0.8–175 μg L−1 with a detection limit of 0.368 μg L−1. The smartphone-based visible readout exhibited a good effect, with a detection limit of 4.067 μg L−1, and recovery of 88 %–103% in food samples. A parallel analysis in food samples was conducted by high-performance liquid chromatography, the results showed good consistency, indicating the practicability of the developed method. Dual mode analysis can avoid the disadvantages of a single response, providing excellent sensitivity, specificity, and efficiency through a strong binding force between the target and the artificial receptors.

Aptamer-mediated N/Ce-doped carbon dots as a fluorescent and resonance Rayleigh scattering dual mode probe for arsenic(III).

Carbon dots doped with N/Ce, N/Eu and N/Tb were prepared by a microwave based hydrothermal technique. The fluorescence of the N/Ce co-doped carbon dots (CDN/Ce) is strongest. They have excitation/emission maxima at 340/441nm. CDN/Ce was characterized by scanning electron microscopy, infrared and fluorescence spectroscopy. On addition of the nucleic acid aptamer (Apt) against arsenic(III) in pH7 solution, the blue fluorescence of the doped carbon dots is partially quenched due to electrostatic interaction. On addition of As(III), it will bind to the aptamer, and the carbon dots are released. Hence, fluorescence becomes gradually restored. In addition, the resonance Rayleigh scattering signal (measured at 340nm) is reduced. This dual-mode assay works in the 0.5-5.8μg·L-1 As(III) concentration range and has a 0.2μg·L-1 detection limit. Graphical abstract Schematic representation of fluorometric and resonance Rayleigh scattering dual mode analysis of As3+ by usingcoupled Apt and CDN/Ce probes. Apt:Aptamer. CD:Carbon dot. Flu:Fluorescence. RRS:Resonance Rayleigh scattering.

A Social Network Analysis of 140 Community-Academic Partnerships for Health: Examining the Healthier Wisconsin Partnership Program.

Social Network Analysis (SNA) provides an important, underutilized approach to evaluating Community Academic Partnerships for Health (CAPHs). This study examines administrative data from 140 CAPHs funded by the Healthier Wisconsin Partnership Program (HWPP). Funder data was normalized to maximize number of interconnections between funded projects and 318 non-redundant community partner organizations in a dual mode analysis, examining the period from 2003-2013.Two strategic planning periods, 2003-2008 vs. 2009-2014, allowed temporal comparison. Connectivity of the network was largely unchanged over time, with most projects and partner organizations connected to a single large component in both time periods. Inter-partner ties formed in HWPP projects were transient. Most community partners were only involved in projects during one strategic time period. Community organizations participating in both time periods were involved in significantly more projects during the first time period than partners participating in the first time period only (Cohen's d = 0.93). This approach represents a significant step toward using objective (non-survey) data for large clusters of health partnerships and has implications for translational science in community settings. Considerations for government, funders, and communities are offered. Examining partnerships within health priority areas, orphaned projects, and faculty ties to these networks are areas for future research.

Gas transport properties of HTPB based polyurethane/cosalen membrane

Polyurethane (PU) membranes own high gas permeability but low selectivity. In the past, some attempts to increase the gas selectivity by modifying the polymer structure but the effort were unsuccessful. There were other attempts to improve the gas separation by the addition of high affinity salt into a membrane. It was reported that increasing the amount of oxygen carrier salt (cosalen) into a polycarbonate membrane did increase the selectivity of oxygen to nitrogen especially at low temperature [G. Galland, T.M. Lam, J. Appl. Polym. Sci. 50 (1993) 1041]. An increase in salt addition reduced the gas diffusivity but increased the diffusivity ratio of oxygen to nitrogen. In another study, it was also found that the addition of high oxygen-affinity salt into a polycarbonate membrane did not greatly increase the solubility ratio of oxygen to nitrogen but it significantly increased the diffusivity ratio of oxygen to nitrogen [Rouh-Chyu Ruaan, Shih-Hsiung, Chen, Juin-Yih Lai, J. Membr. Sci. 135 (1997) 9]. In this study, the effects of oxygen carrier salt namely, cosalen, in PU membrane on gas separation performance was examined. Gas diffusion and sorption properties were examined by sorption measurements and dual mode analyses. The dual mode analysis showed that the gas separation in PU membrane was dominated by gas diffusion rather than gas sorption. The selectivity of O 2/N 2 was 8.6 and the oxygen permeability was 1.1 barrer for the PU membrane with 5 wt.% cosalen at 5°C. The key issue of improving the gas separation performance of a polyurethane membrane was to increase the diffusivity ratio but not the solubility ratio.

Measurement of Molecular Species of Arsenic and Tin Using Elemental and Molecular Dual Mode Analysis by Ionspray Mass Spectrometry

Ionspray mass spectrometry has been employed for dual mode, molecular and elemental, detection and quantification of tributyltin and arsenobetaine. A selectable degree of ion–solvent declustering and molecular fragmentation in the ion source–mass spectrometer interface region permitted detection of fully intact molecular species, or fragments of the molceular species to any selected degree. Complete dissociation of the molecular species in the interface region enabled detection of the underlying element of interest. Tandem mass spectrometry (MS–MS) was used in the molecular detection mode to increase selectivity of the analysis. Instrumental parameter adjustment permitted dual mode detection for the same sample on subsequent injections. Dual mode detection using FI was performed to determine the tributyltin concentration in the National Research Council of Canada (NRCC) harbour sediment reference material PACS-1. Measured tributyltin concentrations were 1.24±0.04 µg g -1 of Sn in the sediment (MS–MS mode) and 1.29±0.04 µg g -1 of Sn in sediment (elemental mode), compared with the certified value of 1.27±0.22 µg g -1 of Sn in sediment. The dual mode detection system was coupled to two forms of liquid chromatography, cation exchange and ion-pairing, to determine arsenobetaine concentration in the NRCC dogfish muscle reference material DORM-2, as part of the NRCC certification process. Results of the two detection modes with both chromatographic methods were consistent, and yielded a mean arsenobetaine concentration of 16.6±0.6 µg g -1 of As in the material. Although the certification process is not complete, this result was consistent with an expected arsenobetaine level slightly higher than previously measured values of 15.7±0.4 µg g -1 of As in for DORM-1, the NRCC predecessor reference material to DORM-2. Additionally, an intermediate mode of interface fragmentation coupled with MS–MS enabled the detailed mapping of possible collisionally induced dissociation channels for arsenobetaine.