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Rapid and Sensitive Determination of ChE Activity in Blood Plasma
Andrej Jerkič, Tjaša Birsa, Mojca Žorž, Dorota Korte, Martina Bergant Marušič, Mladen Franko, 2018, published scientific conference contribution abstract

Found in: ključnih besedah
Summary of found: ...flow injection analysis,thermal lens spectrometric detection, acetylcholinesterase, butyrylcholinesterase, enzyme activity...
Keywords: flow injection analysis, thermal lens spectrometric detection, acetylcholinesterase, butyrylcholinesterase, enzyme activity
Published: 16.07.2018; Views: 2895; Downloads: 0
.pdf Fulltext (642,94 KB)

Nanobodies as convenient reagents for multiple biotechnological applications
Ario De Marco, invited lecture at foreign university

Found in: ključnih besedah
Summary of found: ...biomarker detection, immunocapture, nanobodies...
Keywords: biomarker detection, immunocapture, nanobodies
Published: 17.09.2018; Views: 1849; Downloads: 0
.pdf Fulltext (4,47 MB)

Recombinant nanobodies as cheap and customizable reagents for unicellular algae detection
Elisa Mazzega, Ario De Marco, Marina Cabrini, Alfred Beran, published scientific conference contribution abstract

Abstract: At the present, the identification of planktonic species in coastal water mainly relies on light microscopy observations. This kind of analyses is performed by highly trained personnel, requires lab equipment and long processing time. High-throughput and easy-to-perform methods are instead highly needed for routine costal and ballast water monitoring. Immuno-reagents are widely employed in the medical field for routine diagnostics, where they provide the necessary sensitivity and specificity, as for example for cancer subtype characterization. Reagents of similar grade are so far not widely available for both diagnostics and basic research of microalgae. We describe the first successful isolation of a single-domain antibody (nanobody or VHH) from a pre-immune library, its engineering into application-ready reagents, and its inexpensive production as recombinant fusion protein. Alexandrium minutum was chosen as a model organism to test the feasibility of the procedure. The procedure foresees the panning of a pre-immune phage library of VHHs that was used for in vitro selection against directly the target cells. Monoclonal nanobodies specific for A. minutum cells were identified and optimized for recombinant production as fusion with fluorescent proteins in bacterial hosts. Such fluorescently-tagged VHHs were validated by immunofluorescence and cytofluorimetry for their selectivity by testing unicellular algal species that can be found in the same environment of A. minutum. Two nanobodies were found to be highly specific for the target cells, were able to bind also cysts of A. minutum and they gave no cross-reaction, even for a not-toxic strain of the closely related A. tamutum. Different tags can be then fused to the selected nanobodies and used instead of the fluorescent proteins to obtain a reagent immediately applicable to further techniques, such as cell Enzyme Linked Immuno Sorbent Assay (ELISA) or biosensor surface functionalization. The newly produced reagents can be applied for direct whole-cell detection in seawater, bypassing the need of cell processing required for DNA or RNA diagnostics, and can be used for both alive and fixed cells, guaranteeing the possibility to check old samples and to perform confirmatory morphological studies.
Found in: ključnih besedah
Keywords: Nanobodies, toxic algae, detection, recombinant reagent, naive library, phage display
Published: 21.12.2018; Views: 2407; Downloads: 0
.pdf Fulltext (4,97 MB)

Photothermal lens technique: a comparison between conventional and self-mixing schemes
John Fredy Barrera Ramírez, Dorota Korte, Jose Juan Suárez-Vargas, Jehan Akbar, Evelio E. Ramírez-Miquet, Fatima Matroodi, Imrana Ashraf, Humberto Cabrera, Hanna Budasheva, Joseph J. Niemela, 2019, original scientific article

Abstract: This work focuses on assessing the analytical capabilities of a new photothermal lens method based on the self-mixing effect to reliably measure metallic traces in water-ethanol solutions. We compare it with the conventional thermal lens scheme, considering the low detection limit and versatility. A theoretical model is presented to describe the laser power variations as a function of the photothermal parameters of the analyzed sample. The experimental results demonstrate that the laser intensity variations, induced by the external optical feedback, are governed by the photothermal lens effect. Measurements of Fe(II)-1,10-phenanthroline in water–ethanol solutions show a favourable correspondence and agreement with the theory. The low detection limits obtained by the two analytic techniques also agree very well. Nevertheless, our instrument presents advantages regarding compactness and simplicity, suggesting that this platform could be potentially useful as a robust analytical tool for metallic trace detection. In addition, calibration of the method is performed by measuring the so-called self-mixing constant.
Found in: ključnih besedah
Summary of found: ...conventional thermal lens scheme, considering the low detection limit and versatility. A theoretical model is...
Keywords: thermal lens, photothermal spectroscopy, self-mixing effect, trace detection
Published: 05.04.2019; Views: 2143; Downloads: 0
.pdf Fulltext (715,09 KB)

Increased sensitivity in proton transfer reaction mass spectrometry by incorporation of a radio frequency ion funnel
Andrew M Ellis, Stephen Mullock, Fraser Reich, Paul S Monks, Iain R White, Robert S Blake, Shane Barber, 2012, original scientific article

Abstract: A drift tube capable of simultaneously functioning as an ion funnel is demonstrated in proton transfer reaction mass spectrometry (PTR-MS) for the first time. The ion funnel enables a much higher proportion of ions to exit the drift tube and enter the mass spectrometer than would otherwise be the case. An increase in the detection sensitivity for volatile organic compounds of between 1 and 2 orders of magnitude is delivered, as demonstrated using several compounds. Other aspects of analytical performance explored in this study include the effective E/N (ratio of electric field to number density of the gas) and dynamic range over which the drift tube is operated. The dual-purpose drift tube/ion funnel can be coupled to various types of mass spectrometers to increase the detection sensitivity and may therefore offer considerable benefits in PTR-MS work.
Found in: ključnih besedah
Summary of found: the case. An increase in the detection sensitivity for volatile organic compounds of between...
Keywords: Analytical performance, Detection sensitivity, Drift tube, Dynamic range, Ion funnels, Proton-transfer reaction mass spectrometry, Volatile organic compounds
Published: 18.07.2019; Views: 1707; Downloads: 0
.pdf Fulltext (799,47 KB)

A DNA origami plasmonic sensor with environment-independent read-out
Matjaž Valant, Mattia Fanetti, 2019, original scientific article

Found in: ključnih besedah
Summary of found: ...DNA origami, plasmonic sensor, molecular detection, gold nanoparticle...
Keywords: DNA origami, plasmonic sensor, molecular detection, gold nanoparticle
Published: 08.11.2019; Views: 1813; Downloads: 0
.pdf Fulltext (2,72 MB)

A multi-thermal-lens approach to evaluation of multi-pass probe beam configuration in thermal lens spectrometry
Humberto Cabrera, Leja Goljat, Dorota Korte, Ernesto Marin, Mladen Franko, original scientific article

Abstract: In this work, a recently proposed thermal lens instrument based on multi-pass probe beam concept is investigated and described as a multi-thermal-lens equivalent system. A simulation of the photothermal lens signal formation in a multi-thermal-lens equivalent configuration of the system is performed and validated by comparing the experimental signals of single, dual and ten-pass configurations to theoretically calculated values. The theoretically predicted enhancement of the signal is 9 to 10-fold for a weak thermal lens when comparing the ten-pass configuration with the conventional single-pass thermal lens system. Experimentally achieved signal enhancement in the ten-pass system is 8.3 for pure ethanol sample and between 8 and 9 for solutions with different concentrations of the Fe(II) - 1,10-Phenanthroline complex. Additionally, a value of 9.1 was calculated as the ratio of the slopes of the calibration lines obtained using the ten-pass and single-pass configurations. The achieved limit of detection for determination of Fe(II), in the ten-pass configuration, was 0.4 µgL-1, with a relative standard deviation around 4.5%, which compares favorably with previously reported results for TLS determination of Fe(II) in thin samples using low excitation power. For the multi-pass configuration the linear range of measurement is reduced when compared to the single-pass configuration. This is explained by the theoretical analysis of the photothermal signal under multi-pass condition, which shows the important contribution of the nonlinear term in the theoretical expression for the photothermal signal. The ten-pass configuration, which is presented and validated experimentally for the first time, offers important signal enhancement needed in recently developed TLS instruments with tunable, low power excitation sources.
Found in: ključnih besedah
Summary of found: ...and single-pass configurations. The achieved limit of detection for determination of Fe(II), in the ten-pass...
Keywords: Thermal lens spectrometry, Photothermal detection, Trace determination, Chemical sensor
Published: 10.12.2019; Views: 1900; Downloads: 0
.pdf Fulltext (656,75 KB)

Study of UHECR Composition Using Telescope Array's Middle Drum Detector and Surface Array in Hybrid Mode
J. P. Lundquist, 2016, published scientific conference contribution

Abstract: The seven year Telescope Array (TA) Middle Drum hybrid composition measurement shows agreement between Ultra-High Energy Cosmic Ray (UHECR) data and a light composition obtained with QGSJetII-03 or QGSJet-01c models. The data are incompatible with a pure iron composition, for all models examined, for energies log10(E/eV)>18.4. This is consistent with previous TA results. This analysis is presented using an updated version of the pattern recognition analysis (PRA) technique developed by TA.
Found in: ključnih besedah
Summary of found: ...UHECR, cosmic rays, hybrid detection, composition...
Keywords: UHECR, cosmic rays, hybrid detection, composition
Published: 29.04.2020; Views: 1373; Downloads: 52
.pdf Fulltext (150,19 KB)

TARA: Forward-scattered radar detection of UHECR at the telescope array
J. P. Lundquist, J. Belz, 2013, published scientific conference contribution

Abstract: Increased event statistics will be required to definitively answer the question of the origin(s) of Ultra-High Energy Cosmic Rays (UHECR). Using current technologies however, achieving the necessary statistics may be financially and practically impossible. We describe the status and plans of the TARA project, an effort to detect Ultra-High-Energy Cosmic Rays by their forward scattered or “bistatic” radar signature. Bistatic radar holds promise as a new remote sensing technique for UHECR, without the duty cycle limitations of nitrogen fluorescence detectors. Such a technique could prove key in advancing the study of UHECR beyond the constraints of the current generation of cosmic ray observatories. TARA consists of a low-VHF television transmitter illuminating the air above the Telescope Array (TA), and a set of radio receivers on the far side of TA approximately 50 km distant from the transmitter. We have collected radar data since April 2011 using a 2 kW transmitter at 54.1 MHz. Recently, we received permission to increase our broadcast power to 40 kW and our effective radiated power (ERP) to 6 MW. On the receiver end, we are employing software-defined radio receivers and developing real-time trigger algorithms based on the expected air shower radar echo. In addition to presenting an overview of the project status and future plans, we will present the most recent results of searches for coincidences between radar echoes and Telescope Array air shower events.
Found in: ključnih besedah
Keywords: UHECR, cosmic rays, radar detection
Published: 29.04.2020; Views: 1449; Downloads: 61
.pdf Fulltext (623,59 KB)

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