Multiwavelength bioaerosol sensor performance modeling

Campbell, Scot E.; Tremblay, David P.; Daver, Freddie; Cousins, Daniel

doi:10.1117/12.629081

Cited by 6 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3b). 5,8,9,14,[16][17][18] Since the peaks observed in the B. globigii spectra can be shifted in respect of those observed in unbound fluorophores due to an inhomogeneous environment, it is difficult to unambiguously assign the blue-green emission to particular autofluorphores. Nevertheless, the most probable assignment is that the blue band in B. globigii is mainly due to DPA and NADH, whereas the green band is due to flavins.…”

Section: Biological Materials and Interferantsmentioning

confidence: 99%

See 1 more Smart Citation

Optimization of a UV light-emitting diode based fluorescence-phase sensor

et al. 2006

View full text Add to dashboard Cite

A set of UV light-emitting diodes (LEDs) with the peak wavelengths ranging from 255 nm to 375 nm was applied for the investigation of spectral and decay-time fluorescence signatures in dry B. globigii spores and common airborne interferants (albuminous, epithelium, and cellulosous materials as well as aromatic hydrocarbons). The fluorescence decay signature was represented by a phase shift of the sinusoidal fluorescence waveform in respect of excitation provided by high-frequency modulated LEDs. The obtained data matrix was used for the optimization a bioparticle fluorescence sensor with a minimized number of excitation sources and detection channels and maximized discrimination ability of bioparticles against common interferants. Based on the optimization, a new concept for a UV LED based "detect-to-warn" bioparticle fluorescence sensor is proposed. The sensor contains a single deep-UV LED emitting at 280 nm that is harmonically modulated at a high frequency (of about 70 MHz) and a dual-channel fluorescence detector with the spectral windows peaked at 320 nm and 450 nm. The output parameters of the sensor are the ratio of the fluorescence intensity in the two windows and the phase shift of the fluorescence waveform in the 320-nm detection channel in respect of the excitation one. Such a sensing scheme has a smaller number of optical components and a potentially higher discrimination ability of bioparticles against common interferants in comparison with the conventional approach based on just fluorescence intensity measurement under dual-wavelength excitation (280 nm and 340 nm).

show abstract

Section: Biological Materials and Interferantsmentioning

confidence: 99%

“…[8][9][10] However, there exists no viable concept of a bioparticle fluorescence sensor, which employs an additional detection channel for the characterization of fluorescence decay time. A straightforward introduction of such a channel can result in a significant increase in the sensor price.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a UV light-emitting diode based fluorescence-phase sensor

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Recently, we presented a design methodology for a combined an aerodynamic focusing (AF) inlet and a μ-well trap compatible with a small sample elution volume and in-situ optical analysis [ 37 ]. Fluorescence techniques such as UV laser-induced fluorescence (UV-LIF) and Raman spectroscopy have been used for classification and quantitative determination of the aerosol particles [ 38 – 42 ]. Spectra obtained from a cluster of aerosol particles collected on the substrate provide the information about chemical compositions and biological identification of the particles.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

He¹,

Beck²,

Kossik³

et al. 2018

PLoS ONE

View full text Add to dashboard Cite

Bioaerosol sampling and identification are vital for the assessment and control of airborne pathogens, allergens, and toxins. In-situ analysis of chemical and biological particulate matter can significantly reduce the costs associated with sample preservation, transport, and analysis. The analysis of conventional filters is challenging, due to dilute samples in large collection regions. A low-cost cartridge for collection and analysis of aerosols is developed for use in epidemiological studies and personal exposure assessments. The cartridge collects aerosol samples in a micro-well which reduces particles losses due to the bounce and does not require any coating. The confined particle collection area (dwell~1.4 mm) allows reducing the elution volume for subsequent analysis. The performance of the cartridge is validated in laboratory studies using aerosolized bacterial spores (Bacillus subtilis). Colony forming unit analysis is used for bacterial spore enumeration. Cartridge collection efficiency is evaluated by comparison with the reference filters and found to be consistent with tested flow rates. Sample recovery for the pipette elution is ~80%. Due to the high density of the collected sample, the cartridge is compatible with in-situ spectroscopic analysis and sample elution into the 10–20 μl liquid volume providing a significant increase in sample concentration for subsequent analysis.

show abstract

“…xtensive research has focused on the semiconductor alloy AlGaN due to its application in devices such as field-effect transistors and ultraviolet light-emitting diodes (LEDs) as well as blue and violet laser diodes (LDs). [1][2][3][4][5] A critical issue in the growth of AlGaN is the control of stress during heteroepitaxy. The inclination of threading dislocations (TDs) has been reported to play a role in strain relaxation and generation in high Al-fraction AlGaN.…”

mentioning

confidence: 99%

Inclined Dislocation Generation in Compressive-Strain-Enhanced Mg-Doped GaN/Al_0.15Ga_0.85N Superlattice with AlN Interlayer

Ding

Wei

et al. 2013

Appl. Phys. Express

View full text Add to dashboard Cite

The a- and a+c-type threading dislocation (TD) inclinations were observed in Mg-doped tensile-strained GaN/Al0.15Ga0.85N superlattice (SL) with a high-temperature (HT) AlN interlayer (IL). Most of the inclined dislocations are a-type, toward the equivalent [11̄00] line direction, following dislocation climb model, while a+c-type dislocations gliding on (11̄01) second slip plane inclined toward the [112̄0] line direction. The analysis by comparing samples gave no evidence of Mg dopants to affect the TD inclination. The stress evolution, specifically, the stress transformation of the tensile-stress-relieved AlGaN barrier to the compressive-strain-enhanced GaN well caused by the HT-AlN IL, dominantly affected the a- and a+c-type TD inclinations.

show abstract

Multiwavelength bioaerosol sensor performance modeling

Cited by 6 publications

References 2 publications

Optimization of a UV light-emitting diode based fluorescence-phase sensor

Optimization of a UV light-emitting diode based fluorescence-phase sensor

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

Inclined Dislocation Generation in Compressive-Strain-Enhanced Mg-Doped GaN/Al_0.15Ga_0.85N Superlattice with AlN Interlayer

Contact Info

Product

Resources

About

Multiwavelength bioaerosol sensor performance modeling

Cited by 6 publications

References 2 publications

Optimization of a UV light-emitting diode based fluorescence-phase sensor

Optimization of a UV light-emitting diode based fluorescence-phase sensor

Evaluation of micro-well collector for capture and analysis of aerosolized Bacillus subtilis spores

Inclined Dislocation Generation in Compressive-Strain-Enhanced Mg-Doped GaN/Al0.15Ga0.85N Superlattice with AlN Interlayer

Contact Info

Product

Resources

About

Inclined Dislocation Generation in Compressive-Strain-Enhanced Mg-Doped GaN/Al_0.15Ga_0.85N Superlattice with AlN Interlayer