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1
Majima, Yutaka, Shin-ichiro Miyamoto, Yutaka Oyama e Mitsumasa Iwamoto. "Tunneling Current and Surface Potential Simultaneous Measurement Using a Scanning Probe". Japanese Journal of Applied Physics 37, Part 1, No. 8 (15 agosto 1998): 4557–60. http://dx.doi.org/10.1143/jjap.37.4557.
2
Spurgeon, H. A., M. D. Stern, G. Baartz, S. Raffaeli, R. G. Hansford, A. Talo, E. G. Lakatta e M. C. Capogrossi. "Simultaneous measurement of Ca2+, contraction, and potential in cardiac myocytes". American Journal of Physiology-Heart and Circulatory Physiology 258, n. 2 (1 febbraio 1990): H574—H586. http://dx.doi.org/10.1152/ajpheart.1990.258.2.h574.
Abstract (sommario):
A system is described that can simultaneously record cytosolic Ca2+ concentration ([Ca2+]i), cell length, and either membrane potential or current in single cardiac myocytes loaded with the fluorescent Ca2+ indicator indo-1. Fluorescence is excited by epi-illumination with 3.8-microsecond flashes of 350 +/- 5 nm light from a xenon arc. Indo-1 fluoresence is measured simultaneously in spectral windows of 391-434 nm and 457-507 nm, and the ratio of indo-1 emission in the two bands is computed as a measure of [Ca2+]i for each flash. With cells loaded with the permeant acetoxymethyl ester of indo-1, quantitation of [Ca2+]i is not precise, owing to subcellular compartmentation of indo-1; however, the instrument would allow full quantitation if indo-1 free acid was introduced by microinjection. Simultaneously, cell length is measured on-line from the bright-field image of the cell. Because fluorescence collection is time gated during the brief flash, and red light (650-750 nm) is used for the bright-field image, cell length and [Ca2+]i measurements are obtained simultaneously without cross talk. Membrane potential or current can be recorded simultaneously with indo-1 fluorescence and cell length via standard patch-clamping techniques.
3
Jourdain de Thieulloy, Marilou, Mairi Dorward, Chris Old, Roman Gabl, Thomas Davey, David M. Ingram e Brian G. Sellar. "On the Use of a Single Beam Acoustic Current Profiler for Multi-Point Velocity Measurement in a Wave and Current Basin". Sensors 20, n. 14 (12 luglio 2020): 3881. http://dx.doi.org/10.3390/s20143881.
Abstract (sommario):
Harnessing the energy of tidal currents has huge potential as a source of clean renewable energy. To do so in a reliable and cost effective way, it is critical to understand the interaction between tidal turbines, waves, and turbulent currents in the ocean. Scaled testing in a tank test provides a controlled, realistic, and highly reproducible down-scaled open ocean environment, and it is a key step in gaining this understanding. Knowledge of the hydrodynamic conditions during tests is critical and measurements at multiple locations are required to accurately characterise spatially varying flow in test tank facilities. The paper presents a laboratory technique using an acoustic velocimetry instrument, the range over-which measurements are acquired being more akin to open water applications. This enables almost simultaneous multi-point measurements of uni-directional velocity along a horizontal profile. Velocity measurements have been obtained from a horizontally mounted Single Beam Acoustic Doppler (SB-ADP) profiler deployed in the FloWave Ocean Energy Research Facility at the University of Edinburgh. These measurements have been statistically compared with point measurements obtained while using a co-located Acoustic Doppler Velocimeter (ADV). Measurements were made with both instruments under flow velocities varying from 0.6 ms−1 to 1.2 ms−1, showing that flow higher than 1 ms−1 was more suitable. Using a SB-ADP has shown the advantage of gaining 54 simultaneous measurement points of uni-directional velocity, covering a significant area with a total distance of 10 m of the test-tank, at a measurement frequency of 16 Hz. Of those measurement points, 41 were compared with co-located ADV measurements covering 8 m of the profile for a tank nominal flow velocity of 0.8 ms−1, and four distributed locations were chosen to to carry out the study at 0.6 ms−1, 1.0 ms−1, and 1.2 ms−1. The comparison with the ADV measurement showed a 2% relative bias on average.
4
Oyama, Yutaka, Yutaka Majima e Mitsumasa Iwamoto. "Analysis of scanning probe used for simultaneous measurement of tunneling current and surface potential". Journal of Applied Physics 86, n. 12 (15 dicembre 1999): 7087–93. http://dx.doi.org/10.1063/1.371796.
5
HUDDAR, B. B., e K. R. RAO. "A combined sonde for the measurement of electrical conductivity and potential gradient in the atmosphere". MAUSAM 23, n. 2 (3 febbraio 2022): 185–88. http://dx.doi.org/10.54302/mausam.v23i2.5276.
Abstract (sommario):
The paper describes a combined sonde for the simultaneous measurement of the vertical distribution of electrical conductivity and potential gradient in the upper atmosphere during a balloon flight. The data obtained helps in evaluating the third parameter, i.e., air earth conduction current at all levels. Thus all the three main parameters of the atmosphericelectrioity can be measured with a single sonde. A typical sounding taken with the above instrument is also presented.
6
Mulberry, Geoffrey, Kevin A. White, Matthew A. Crocker e Brian N. Kim. "A 512-Ch Dual-Mode Microchip for Simultaneous Measurements of Electrophysiological and Neurochemical Activities". Biosensors 13, n. 5 (26 aprile 2023): 502. http://dx.doi.org/10.3390/bios13050502.
Abstract (sommario):
In the study of the brain, large and high-density microelectrode arrays have been widely used to study the behavior of neurotransmission. CMOS technology has facilitated these devices by enabling the integration of high-performance amplifiers directly on-chip. Usually, these large arrays measure only the voltage spikes resulting from action potentials traveling along firing neuronal cells. However, at synapses, communication between neurons occurs by the release of neurotransmitters, which cannot be measured on typical CMOS electrophysiology devices. Development of electrochemical amplifiers has resulted in the measurement of neurotransmitter exocytosis down to the level of a single vesicle. To effectively monitor the complete picture of neurotransmission, measurement of both action potentials and neurotransmitter activity is needed. Current efforts have not resulted in a device that is capable of the simultaneous measurement of action potential and neurotransmitter release at the same spatiotemporal resolution needed for a comprehensive study of neurotransmission. In this paper, we present a true dual-mode CMOS device that fully integrates 256-ch electrophysiology amplifiers and 256-ch electrochemical amplifiers, along with an on-chip 512 electrode microelectrode array capable of simultaneous measurement from all 512 channels.
7
Yokota, Kazumichi, Muneaki Hashimoto, Kazuaki Kajimoto, Masato Tanaka, Sanae Murayama, Makusu Tsutsui, Yoshihiro Nakajima, Masateru Taniguchi e Masatoshi Kataoka. "Effect of Electrolyte Concentration on Cell Sensing by Measuring Ionic Current Waveform through Micropores". Biosensors 11, n. 3 (12 marzo 2021): 78. http://dx.doi.org/10.3390/bios11030078.
Abstract (sommario):
Immunostaining has been widely used in cancer prognosis for the quantitative detection of cancer cells present in the bloodstream. However, conventional detection methods based on the target membrane protein expression exhibit the risk of missing cancer cells owing to variable protein expressions. In this study, the resistive pulse method (RPM) was employed to discriminate between cultured cancer cells (NCI-H1650) and T lymphoblastoid leukemia cells (CCRF-CEM) by measuring the ionic current response of cells flowing through a micro-space. The height and shape of a pulse signal were used for the simultaneous measurement of size, deformability, and surface charge of individual cells. An accurate discrimination of cancer cells could not be obtained using 1.0 × phosphate-buffered saline (PBS) as an electrolyte solution to compare the size measurements by a microscopic observation. However, an accurate discrimination of cancer cells with a discrimination error rate of 4.5 ± 0.5% was achieved using 0.5 × PBS containing 2.77% glucose as the electrolyte solution. The potential application of RPM for the accurate discrimination of cancer cells from leukocytes was demonstrated through the measurement of the individual cell size, deformability, and surface charge in a solution with a low electrolyte concentration.
8
Ajito, Saya, Eiji Tada, Azusa Ooi e Atsushi Nishikata. "Simultaneous Measurements of Corrosion Potential and Hydrogen Permeation Current in Atmospheric Corrosion of Steel". ISIJ International 59, n. 9 (15 settembre 2019): 1659–66. http://dx.doi.org/10.2355/isijinternational.isijint-2019-113.
9
Ozaki, H., R. J. Stevens, D. P. Blondfield, N. G. Publicover e K. M. Sanders. "Simultaneous measurement of membrane potential, cytosolic Ca2+, and tension in intact smooth muscles". American Journal of Physiology-Cell Physiology 260, n. 5 (1 maggio 1991): C917—C925. http://dx.doi.org/10.1152/ajpcell.1991.260.5.c917.
Abstract (sommario):
Microelectrode techniques and the fluorescent Ca2+ indicator indo-1 were used to measure membrane potential, cytosolic Ca2+ ([Ca2+]cyt), and muscle tension simultaneously in canine antral smooth muscles. Responses of muscles from the myenteric and submucosal regions were compared, since electrical activity and excitation-contraction coupling in these regions differ. The upstroke phase of electrical slow waves in both regions induced an increase in [Ca2+]cyt. In myenteric muscles the plateau phase of slow waves often caused either a further rise in [Ca2+]cyt or maintenance of the level reached during the upstroke event. In submucosal muscles, the plateau phase was significantly smaller and did not induce a second phase in the Ca2+ transient. Contractions were related to the amplitudes of Ca2+ transients. Acetylcholine (ACh; 3 x 10(-8)-10(-6) M) increased the amplitude and duration of the plateau phase of slow waves in a concentration-dependent manner. ACh also increased the second phase of Ca2+ transients and contractile responses associated with the plateau potential. In submucosal muscles ACh induced a significant increase in the plateau phase of the slow wave and increased the corresponding phase of Ca2+ transient. Nicardipine (10(-6) M) inhibited plateau phase of slow waves and the associated increases in [Ca2+]cyt and muscle tension. BAY K 8644 (10(-7) M) augmented the plateau potential and increased [Ca2+]cyt and muscle tension. These results suggest that dihydropyridine-sensitive Ca2+ currents participate in the plateau potential. Cholinergic stimulation modulates [Ca2+]cyt and therefore force by regulating the amount of Ca2+ entering cells through these channels.
10
Smirnova, N. F., e G. Stanev. "Estimation of the Electron Density in the Near 3–4 RE Magnetosphere Based on the Measurement of the Interball-2 Satellite Potential". Космические исследования 61, n. 3 (1 maggio 2023): 202–14. http://dx.doi.org/10.31857/s0023420622700066.
Abstract (sommario):
A new method is proposed for determining the electron density in rarefied plasma, based on simultaneous measurements of the Interball-2 satellite potential using IESP-2 (electric field instrument) and KM-7 (electron temperature sensor) probe devices. This makes it possible to estimate the photoelectron current density based on a procedure proposed earlier by the authors of this study. The electron concentration was determined only for the positive potential of the spacecraft. The balance equations for the satellite and the probe between the currents of the surrounding plasma electrons and photoelectrons emitted by the illuminated surface were compiled. In the magnetosphere, to bring the probe potential to the potential of the surrounding plasma, a bias current is directed into the probe, which was taken into account in the current balance equation for the probe. The electron energy used in the calculations was kTe = 1 eV. We analyzed data from ~350 orbits in the auroral region of the magnetosphere at altitudes of 2–3 RE from October 1996 to March 1998 during the period of low solar activity at the beginning of the 23rd cycle. Examples of the calculated electron density are given, which is in the range of 1–30 cm–3.
11
Pirnaris, Panagiotis, e Theodoros Sarris. "Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere". Annales Geophysicae 41, n. 2 (11 settembre 2023): 339–54. http://dx.doi.org/10.5194/angeo-41-339-2023.
Abstract (sommario):
Abstract. Simultaneous knowledge of the temperatures of electrons, ions and neutrals is key to the understanding and quantification of energy transfer processes in planetary atmospheres. However, whereas electron and ion temperature measurements are routinely obtained from ground-based incoherent scatter radars, simultaneous measurements of electron, ion and neutral temperature measurements can only be made in situ. For the Earth's lower thermosphere–ionosphere, the only available comprehensive in situ dataset of electron, ion and neutral temperatures to date is that of the Atmosphere Explorers C, D and E and the Dynamics Explorer 2 missions. In this study we first perform a cross-comparison of all co-temporal and co-spatial measurements between in situ electron and ion temperature measurements from the above in situ spacecraft missions with corresponding measurements from the Arecibo, Millstone Hill and Saint-Santin incoherent scatter radars, during times of overflights of these spacecraft over the radar fields of view. This expands upon a previous study that only considered data from the Atmosphere Explorer C. The results indicate good agreement between satellite and ground-based radar measurements. Subsequently, out of the above datasets, all instances where ion temperatures appear to be lower than neutral temperatures are identified and are studied statistically. Whereas current understanding indicates that ion temperatures are generally expected to be higher than neutral temperatures in the lower thermosphere–ionosphere, a non-negligible number of events is found where this does not hold true. The distribution of all such cases in altitude, latitude and longitude is presented and discussed. Potential causes leading to neutral temperatures being higher than ion temperatures are outlined, including both instrumental effects or measurement errors and physical causes. Whereas a conclusive case cannot be made based on the present analysis, it is speculated from the results presented herein that not all cases can be attributed to instrument effects or measurement errors. This can have significant implications for the current understanding that the energy of the ions is expected to be higher than that of the neutrals and points to the need for additional simultaneous in situ measurements in the lower thermosphere–ionosphere (LTI).
12
Stroobant, Lenka, Siska Croubels, Laura Dhondt, Joske Millecam, Siegrid De Baere, Elke Gasthuys, Joachim Morrens e Gunther Antonissen. "Simultaneous Measurement of Glomerular Filtration Rate, Effective Renal Plasma Flow and Tubular Secretion in Different Poultry Species by Single Intravenous Bolus of Iohexol and Para-Aminohippuric Acid". Animals 10, n. 6 (12 giugno 2020): 1027. http://dx.doi.org/10.3390/ani10061027.
Abstract (sommario):
The aim of the current study was to investigate the simultaneous measurement of plasma p-aminohippuric acid (PAH) clearance as a potential marker to assess effective renal plasma flow (eRPF) and tubular secretion (TS), and the plasma clearance of iohexol (IOH) as a marker of the glomerular filtration rate in poultry species. The PAH was administered intravenously (IV) to broiler chickens, layers, turkeys, Muscovy ducks, and pigeons. Each animal received successively a single bolus dose of 10 mg PAH/kg bodyweight (BW) and 100 mg PAH/kg BW to assess the eRPF and TS, respectively. Simultaneously with both PAH administrations, a single IV bolus of 64.7 mg/kg BW of IOH was administered. A high linear correlation (R2 = 0.79) between eRPF, based on the clearance of the low dose of PAH, and BW was observed for the poultry species. The correlation between TS, based on the clearance of the high dose of PAH, and BW was moderate (R2 = 0.50). Finally, a moderate correlation (R2 = 0.68) was demonstrated between GFR and eRPF and between GFR and TS (R2 = 0.56). This presented pharmacokinetic approach of the simultaneous administration of IOH and PAH enabled a simultaneous evaluation of eRPF/TS and GFR, respectively, in different poultry species.
13
Contant, Stephane, Geoffrey Klein, Jordan Morelli e Thomas W. Krause. "Inverse algorithm for extraction of multiple parameters using analytical model of eddy current response". Journal of Applied Physics 131, n. 20 (28 maggio 2022): 205103. http://dx.doi.org/10.1063/5.0088221.
Abstract (sommario):
Eddy current (EC) technology is commonly used for detecting flaws, measuring geometric parameters, or determining properties of conducting materials. However, the measurement of a particular parameter can become more challenging if multiple influential parameters vary simultaneously. In particular, eddy current-based measurement of separation (gap) between a pressure tube (PT) and a calandria tube (CT) in the fuel channels of CANDU® reactors is made more difficult by variations in PT wall thickness, resistivity, and probe lift-off. An analytical model of the EC response to changes in PT–CT gap has been developed by approximating the geometry of the PT within the larger diameter CT as a pair of concentric tubes, where gap is varied by changing the CT radius. In this article, this model is used in combination with an error minimization algorithm to construct an inverse algorithm for the extraction of PT–CT gap, PT resistivity (ρ), and PT wall thickness (WT) from measured multi-frequency eddy current signals. Application of a linear regression tool in MATLAB, with fourth-order polynomial fitting of modeled data with varying ρ and WT as a function of PT–CT gap, is used to obtain coefficients that depend on ρ and WT. Output of multidimensional fitting of these coefficients is scaled and rotated to calibration data. Finally, implementation of an error minimization algorithm in MATLAB is used to produce estimates of multiple target parameters from experimental data. Simultaneous extraction of either one, two, or three parameters is examined, using experimental data obtained at frequencies used for in-reactor inspection of 4.2, 8, and 16 kHz, or just two frequencies of 4.2 and 8 kHz. Under full gap variation conditions, the inverse algorithm predicts gap to within 0.1 mm at gaps between 0 and 9 mm and to within 0.4 mm at gaps between 9 and 18 mm. PT resistivity is predicted to within 1 μΩ cm (2% relative error) and PT wall thickness within 0.03 mm (1% relative error) when each is the only extracted parameter. An excellent agreement between actual and predicted values of gap demonstrates the potential of the inverse algorithm for application to in-reactor gap measurement and simultaneous extraction of either PT wall thickness or resistivity when the other parameter is known. The extraction of PT resistivity may be particularly useful, as this parameter cannot otherwise currently be measured in-reactor.
14
Gunn, J. P., R. Pánek, J. Stöckel, G. Van Oost e T. Van Rompuy. "Simultaneous measurements of fluctuations of ion current, electron temperature, and floating potential with a tunnel probe". Czechoslovak Journal of Physics 55, n. 3 (marzo 2005): 255–63. http://dx.doi.org/10.1007/s10582-005-0038-6.
15
Werner, Carsten, Ralf Zimmermann e Thomas Kratzmüller. "Streaming potential and streaming current measurements at planar solid/liquid interfaces for simultaneous determination of zeta potential and surface conductivity". Colloids and Surfaces A: Physicochemical and Engineering Aspects 192, n. 1-3 (novembre 2001): 205–13. http://dx.doi.org/10.1016/s0927-7757(01)00725-7.
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Kreta, Ahmed, Miran Gaberšček e Igor Muševič. "Time‐resolved in situ electrochemical atomic force microscopy imaging of the corrosion dynamics of AA2024‐T3 using a new design of cell". Journal of Materials Research 36, n. 1 (15 gennaio 2021): 79–93. http://dx.doi.org/10.1557/s43578-020-00077-2.
Abstract (sommario):
AbstractAn electrochemical cell was designed to enable in situ atomic force microscopy (AFM) measurements. The finite‐element method was implemented using COMSOL Multiphysics to simulate the electrical field within the cell and to find the current and potential distribution. A comparative three‐dimensional simulation study was made to compare two different designs and to elucidate the importance of the geometry on the electrical field distribution. The design was optimized to reduce the uncertainty in the measurement of the electrochemical impedance. Then, an in situ, simultaneous electrochemical and time‐resolved AFM experiments were conducted to study the surface evolution of the aluminum alloy AA2024‐T3 exposed to 0.5 M NaCl. The temporal change of the surface topography was recorded during the application of chrono‐amperometric pulses using a newly designed electrochemical cell. Electrochemical impedance spectroscopy was conducted on the sample to confirm the recorded topographical change. The newly developed cell made it possible to monitor the surface change and the growth of the oxyhydroxide layer on the AA2024‐T3 with the simultaneous application of electrochemical methods.
17
Sim, Daniel (Jai Kyoung), Sung Mok Kim, Steve S. Kim e Il Doh. "Portable Skin Analyzers with Simultaneous Measurements of Transepidermal Water Loss, Skin Conductance and Skin Hardness". Sensors 19, n. 18 (6 settembre 2019): 3857. http://dx.doi.org/10.3390/s19183857.
Abstract (sommario):
Simultaneous measurement of skin physiological and physical properties are important for the diagnosis of skin diseases and monitoring of human performance, since it provides more comprehensive understanding on the skin conditions. Current skin analysis devices, however, require each of probes and unique protocols for the measurement of individual skin properties, resulting in inconvenience and increase of measurement uncertainty. This paper presents a pen-type skin analyzing device capable tomeasure three key skin properties at the same time: transepidermal water loss (TEWL), skin conductance, and skin hardness. It uses a single truncated hollow cone (THC) probe integrated with a humidity sensor, paired electrodes, and a load cell for the multimodal assessment of the skin properties. The present device measured TEWL with a sensitivity of 0.0068 (%/s)/(g/m2/h) and a linearity of 99.63%, conductance with a sensitivity of 1.02 µS/µS and a linearity of 99.36%, and hardness with a sensitivity of 0.98 Shore 00/Shore 00 and a linearity of 99.85%, within the appropriate ranges for the human skin. The present pen-type device has a high potential for the skin health diagnosis as well as the human performance monitoring applications.
18
Xiao, Xia, Hongtian Song e Hongbin Li. "A High Accuracy AC+DC Current Transducer for Calibration". Sensors 22, n. 6 (12 marzo 2022): 2214. http://dx.doi.org/10.3390/s22062214.
Abstract (sommario):
Facing a lack of high accuracy current standards in the calibration of AC (Alternating Current) + DC (Direct Current) measurement devices that function to measure DC and AC simultaneously, a measurement method with high accuracy is proposed based on zero-flux self-oscillating fluxgate. An iron core and two windings are added onto the single-iron-core double-winding structure of the traditional self-oscillating fluxgate. The added iron core and its upper winding are used to weaken the influence of ripple on the sensor’s accuracy. The other one of the added windings is used for the feedback from the AC+DC magnetic potential, allowing the sensor to work in a zero-flux state and to measure AC+DC simultaneously. An AC+DC transducer prototype with an AC ranging from 0–500 A and DC 0–300 A is developed by selecting the core parameters and an optimized design of the circuit. The test results of the prototype show that the prototype can measure the AC and DC simultaneously, and the measurement accuracy reaches class 0.05 level in the nominal current range. This transducer can be used as a calibration standard of measurement devices for AC only, DC only, or AC and DC simultaneously. Compared with the AC+DC current transducer with the same accuracy level, the proposed transducer has fewer cores and simpler measuring circuit.
19
Nose, Kiyomi, Ko-ichiro Miyamoto e Tatsuo Yoshinobu. "Estimation of Potential Distribution during Crevice Corrosion through Analysis of I–V Curves Obtained by LAPS". Sensors 20, n. 10 (19 maggio 2020): 2873. http://dx.doi.org/10.3390/s20102873.
Abstract (sommario):
Crevice corrosion is a type of local corrosion which occurs when a metal surface is confined in a narrow gap on the order of 10 μm filled with a solution. Because of the inaccessible geometry, experimental methods to analyze the inner space of the crevice have been limited. In this study, a light-addressable potentiometric sensor (LAPS) was employed to estimate the potential distribution inside the crevice owing to the IR drop by the anodic current flowing out of the structure. Before crevice corrosion, the I–V curve of the LAPS showed a potential shift, depending on the distance from the perimeter. The shift reflected the potential distribution due to the IR drop by the anodic current flowing out of the crevice. After crevice corrosion, the corrosion current increased exponentially, and a local pH change was detected where the corrosion was initiated. A simple model of the IR drop was used to calculate the crevice gap, which was 12 μm—a value close to the previously reported values. Thus, the simultaneous measurement of the I–V curves obtained using a LAPS during potentiostatic electrolysis could be applied as a new method for estimating the potential distribution in the crevice.
20
JU, BING-FENG, YANG JU e MASUMI SAKA. "NOVEL AFM PROBE FOR LOCAL CONDUCTIVITY MEASUREMENT". International Journal of Nanoscience 05, n. 04n05 (agosto 2006): 413–18. http://dx.doi.org/10.1142/s0219581x06004565.
Abstract (sommario):
A new atomic force microscope (AFM) probe for local conductivity measurement is presented. This silicon nitride based probe with a V-shaped two-dimensional sliced structure tip is patterned by using conventional photolithography method. The probe is then etched to four parallel electrodes that isolated from each other, for the purpose of performing current input and electrical potential drop measurement. The newly developed four-point AFM probe not only inherits the function of AFM surface topography generating but also has the capability of characterizing the local conductivity simultaneously. The nanoresolution position control mechanism of AFM allows the probe scanning across micrometers sized area and creating high spatial resolution map of the in-plane conductivities. Experiments have shown this four-point AFM probe to be mechanically flexible and robust. The repeatable conductivity measurements on the surface of aluminum and indium tin oxide (ITO) thin films indicate this four-point AFM probe technique has potential applications for characterizing devices and materials in microscale.
21
Szabó-Tóth, Kinga, e Attila Papp Z. "Applied Social Scientific Methods for the Measurement of Local Innovation Potential". Theory, Methodology, Practice 15, n. 2 (15 dicembre 2019): 77–88. http://dx.doi.org/10.18096/tmp.2019.02.08.
Abstract (sommario):
The study introduces a methodological tool for measuring local social innovation potential and its application in five settlements in the Abaúj region of northeastern Hungary. When working on the local innovation potential (LIP) index we present in this study, we drew upon existing theories and models of social innovation. The complexity of LIP index comes from the fact that it builds upon both qualitative and quantitative data and research methods. Therefore it is simultaneously based on social scientific methods that are traditionally considered “soft” and “hard”. The LIP index is can take into account local specificities and characteristics into account and is thus suitable for presenting a fine-tuned description of the current situation and characteristics of a settlement, together with its future potential and directions for development.
22
Liu, Yunsong, Jean-Daniel Paris, Gregoire Broquet, Violeta Bescós Roy, Tania Meixus Fernandez, Rasmus Andersen, Andrés Russu Berlanga et al. "Assessment of current methane emission quantification techniques for natural gas midstream applications". Atmospheric Measurement Techniques 17, n. 6 (19 marzo 2024): 1633–49. http://dx.doi.org/10.5194/amt-17-1633-2024.
Abstract (sommario):
Abstract. Methane emissions from natural gas systems are increasingly scrutinized, and accurate reporting requires quantification of site- and source-level measurement. We evaluate the performance of 10 available state-of-the-art CH4 emission quantification approaches against a blind controlled-release experiment at an inerted natural gas compressor station in 2021. The experiment consisted of 17 blind 2 h releases at a single exhaust point or multiple simultaneous ones. The controlled releases covered a range of methane flow rates from 0.01 to 50 kg h−1. Measurement platforms included aircraft, drones, trucks, vans, ground-based stations, and handheld systems. Herewith, we compare their respective strengths, weaknesses, and potential complementarity depending on the emission rates and atmospheric conditions. Most systems were able to quantify the releases within an order of magnitude. The level of errors from the different systems was not significantly influenced by release rates larger than 0.1 kg h−1, with much poorer results for the 0.01 kg h−1 release. It was found that handheld optical gas imaging (OGI) cameras underestimated the emissions. In contrast, the “site-level” systems, relying on atmospheric dispersion, tended to overestimate the emission rates. We assess the dependence of emission quantification performance on key parameters such as wind speed, deployment constraints, and measurement duration. At the low wind speeds encountered (below 2 m s−1), the experiments did not reveal a significant dependence on wind speed. The ability to quantify individual sources degraded during multiple-source releases. Compliance with the Oil and Gas Methane Partnership's (OGMP 2.0) highest level of reporting may require a combination of the specific advantages of each measurement technique and will depend on reconciliation approaches. Self-reported uncertainties were either not available or were based on the standard deviation in a series of independent realizations or fixed values from expert judgment or theoretical considerations. For most systems, the overall relative errors estimated in this study are higher than self-reported uncertainties.
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Orlov, Kirill, Vyacheslav Panarin, Alexey Krivoshapkin, Dmitry Kislitsin, Vadim Berestov, Timur Shayakhmetov e Anton Gorbatykh. "Assessment of periprocedural hemodynamic changes in arteriovenous malformation vessels by endovascular dual-sensor guidewire". Interventional Neuroradiology 21, n. 1 (febbraio 2015): 101–7. http://dx.doi.org/10.15274/inr-2014-10096.
Abstract (sommario):
Endovascular embolization is an important modality in the treatment of brain AVMs. Nowadays staged embolization is the method of choice for the prevention of perioperative hemorrhagic complications. Current theory suggests that simultaneous occlusion of more than 60% of AVM volume induces significant redistribution local blood flow. That, in turn, may lead to hemorrhage due to AVM rupture. Aside from angiographic findings, there is still no method that predicts the degree of safe partial embolization. Intraluminal measurement of flow velocity and pressure in the vicinity of the AVM nidus might allow detecting the changes in local hemodynamics. That can provide a valuable data and shed the light on the origin of vascular catastrophes. Ten patients underwent 12 embolization sessions with intraluminal flow velocity and pressure monitoring. The measurements were performed by dual-sensor guidewire. The “Combomap” (Volcano) system with Combowire microguidewires was chosen for measurements, as there is a documented experience of safe use of said guidewires in the cerebral vasculature. The findings observed during the study matched empirical data as well as the current physiological hypothesis of AVM hemorrhage. In conjunction with DSA runs, intraluminal flow velocity and pressure monitoring has the potential to become a valuable tool in AVM treatment.
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Kaewjumras, Yongyut, Jirawat Prabket, Wisut Titiroongruang e Surasak Niemcharoen. "Contactless Silicon-Based Multi-Dimensional Hall Sensor with Simultaneous Magnetic Sensing and Omni-Rotational Angle Measurement". International Journal of Engineering Research in Africa 41 (febbraio 2019): 51–59. http://dx.doi.org/10.4028/www.scientific.net/jera.41.51.
Abstract (sommario):
This experimental research proposes a contactless silicon-based two-dimensional (2D) Hall sensor capable of simultaneous parallel-and perpendicular-directional magnetic sensing, with a 360° angle measurement. The Hall sensor was of non-symmetrical five-ohmic contact configuration (C1 – C5). In the study, experiments were carried out in three stages. In the first-stage experiment, the current (I) and voltage (V) of the 2D Hall sensor were determined under three schemes: schemes A (C1&C2), B (C2&C5), and C (C3&C4). In the second-stage experiment, the parallel and perpendicular absolute sensitivities of the 2D sensor were examined. Considering the discrepancy between the parallel and perpendicular absolute sensitivities, signal conditioning circuitry was incorporated into the sensor system to compensate, and the rotational angles measured in the final-stage experiment. The results revealed that the I-V curves were dominantly linear, corresponding to Ohm’s law. However, the parallel and perpendicular absolute sensitivities were low and unequal. Thus, signal conditioning circuitry was incorporated into the system to address the discrepancy and improve the performance. Importantly, the 2D Hall sensor exhibited a mere ±3odiscrepancy between the measured and reference rotational angles, given the magnetic flux density of 1000 G, with the hysteresis error of 2.8%. In essence, the proposed contactless silicon-based 2D Hall sensor possesses high potential for high-precision industrial applications.
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de Crespigny, Alexander, Joachim Röther, Nick van Bruggen, Christian Beaulieu e Michael E. Moseley. "Magnetic Resonance Imaging Assessment of Cerebral Hemodynamics during Spreading Depression in Rats". Journal of Cerebral Blood Flow & Metabolism 18, n. 9 (settembre 1998): 1008–17. http://dx.doi.org/10.1097/00004647-199809000-00010.
Abstract (sommario):
High-speed magnetic resonance imaging was used to perform simultaneous measurements of relative cerebral blood volume (rCBV) and water diffusion changes during spreading depression (SD) induced by cortical potassium chloride application. Rats were fitted epidurally with a rubber chamber. Potassium chloride was perfused through the chamber until SD was indicated by a negative direct current (DC) potential shift. Magnetic resonance imaging scans used echo planar diffusion and T2-weighted images. Iron dextran was injected as a blood pool contrast agent to make subsequent changes in T2 (or T2*) directly proportional to changes in CBV. Multislice maps of apparent diffusion coefficient (ADC) and rCBV were generated with 6- to 16-second time resolution, which revealed transient ADC and rCBV changes propagating over the cortex after potassium chloride application. Transient ADC declines appeared simultaneously with the DC shift, whereas rCBV increase followed with a delay of 16.4 ± 14.9 seconds. Prolonged rCBV decrease was observed after the initial increase during the SD in half of the animals. The delayed rCBV response after the ADC change supports the observation of increased energy demand because of repolarization. Simultaneous DC potential recording and ADC measurements in corresponding sites of the cortex indicate that transient ADC decreases during SD reflect water shifts associated with cell depolarization.
26
Liu, Dong, Xiaoting Xiao, Ziqiao Tang, Qiao Chen, Haoran Li, Xiaoxiong Wang e Yan Yan. "Method for QCM Resonator Device Equivalent Circuit Parameter Extraction and Electrode Quality Assessment". Micromachines 12, n. 9 (9 settembre 2021): 1086. http://dx.doi.org/10.3390/mi12091086.
Abstract (sommario):
Quartz crystal microbalance (QCM) resonators are used in a wide range of sensors. Current QCM resonators achieve a simultaneous measurement of multiple physical quantities by analyzing lumped-element equivalent parameters, which are obtained via the introduction of external devices. This introduction of external devices will probably increase measurement error. To realize the measurement of multiple physical quantities while eliminating the measurement error caused by external devices, this paper proposes a measurement method for the lumped-element equivalent parameters of QCM resonators without the need for extra external devices. Accordingly, a numerical method for solving nonlinear equations with fewer data points required and a higher accuracy was adopted. A standard crystal resonator parameter extraction experiment is described. The extracted parameters were consistent with the nominal parameters, which confirms the accuracy of this method. Furthermore, six QCM resonator device samples with different electrode diameters and materials were produced and used in the parameter measurement experiment. The linear relationship between the electrode material conductivity and motional resistance R1 is discussed. The ability of this method to characterize the electrode material and to detect the rust status of the electrode is also demonstrated. These abilities support the potential utility of the proposed method for an electrode quality assessment of piezoelectric devices.
27
Wang, Jin Fen, Chao Bian, Jian Hua Tong, Ji Zhou Sun e Shan Hong Xia. "Electrochemical Measurement of Copper, Lead and Zinc Ions in Tap Water by Using an Environment-Friendly Microelectrode". Key Engineering Materials 562-565 (luglio 2013): 1302–7. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.1302.
Abstract (sommario):
This paper describes the fabrication, characterization and application of an environment-friendly tin film/gold nanoparticles (Sn/AuNPs) modified gold microelectrode for square wave stripping voltammetric (SWSV) determination of copper, lead and zinc. The microelectrode chips were fabricated by Micro Electro-Mechanical System (MEMS) technique. The sensitivity of the modified microelectrode was largely improved due to the large surface area of AuNPs and the formation of alloys between target metals and Sn. The influence of hydrogen overflow was reduced and the current response was enhanced because AuNPs made the stripping potential shift positively and Sn extended the stripping potential range. Combining AuNPs with Sn, the obtained microelectrode exhibited satisfied linearity ranges from 5 to 500 μg L-1 for copper and lead, from 10 to 500 μg L-1 for zinc, with a limit of detection of 2 μg L-1 for copper, 3 μg L-1 for lead and 5 μg L-1 for zinc. The Sn/AuNPs/gold microelectrode was successfully applied for simultaneous detection of copper, lead and zinc in tap water sample.
28
Amodeo, Corrado, Sasha D. Hafner, Rúben Teixeira Franco, Hassen Benbelkacem, Paul Moretti, Rémy Bayard e Pierre Buffière. "How Different Are Manometric, Gravimetric, and Automated Volumetric BMP Results?" Water 12, n. 6 (26 giugno 2020): 1839. http://dx.doi.org/10.3390/w12061839.
Abstract (sommario):
The objectives of this study were to: (1) quantify differences in biochemical methane potential (BMP) measured using three measurement methods, including two popular methods (a commercial automated system (AMPTS II) and manual manometric) and one newer method (gravimetric), and (2) assess the importance of the mixing position in the measurement sequence. Powdered microcrystalline cellulose was used as the substrate in simultaneous tests. All methods gave similar results (<8% difference in the mean BMP) and were reasonably accurate (recovery of 80–86% of the theoretical maximum BMP). Manometric BMP values were consistently lower than gravimetric by 4–5%. Precision was lower for the automated method (relative standard deviation (RSD) of about 7%) than for the manual methods (RSD about 1–3%). Mixing after biogas measurement resulted in 3% higher BMP for both manual methods than mixing before, due to the lower measured CH4 production from blanks. This effect may be linked to a fraction of CH4 that remains dissolved or even as attached bubbles, and suggests that mixing before measurement is preferable. The automated volumetric and gravimetric methods (mode 2) gave very similar mean BMP values (1% different). However, kinetic analysis showed that methane production was faster with the automated volumetric method. This could come from an error in the estimation of the CH4 production rate for the automated method, or an increase in the degradation rate due to better mixing. Both automatic volumetric and manual gravimetric measurements met current validation criteria for mean cellulose BMP, but the RSD from the automated system exceeded the limit.
29
Armitage, Lucy, Kenny Cho, Emre Sariyildiz, Angela Buller, Stephen O’Brien e Lauren Kark. "Validation of a Custom Interface Pressure Measurement System to Improve Fitting of Transtibial Prosthetic Check Sockets". Sensors 23, n. 7 (6 aprile 2023): 3778. http://dx.doi.org/10.3390/s23073778.
Abstract (sommario):
Achievement of fit between the residual limb and prosthetic socket during socket manufacture is a priority for clinicians and is essential for safety. Clinicians have recognised the potential benefits of having a sensor system that can provide objective socket-limb interface pressure measurements during socket fitting, but the cost of existing systems makes current technology prohibitive. This study will report on the characterisation, validation and preliminary clinical implementation of a low cost, portable, wireless sensor system designed for use during socket manufacture. Characterisation and benchtop testing demonstrated acceptable accuracy, behaviour at variable temperature, and dynamic response for use in prosthetic socket applications. Our sensor system was validated with simultaneous measurement by a commercial sensor system in the sockets of three transtibial prosthesis users during a fitting session in the clinic. There were no statistically significant differences between the sensor system and the commercial sensor for a variety of functional activities. The sensor system was found to be valid in this clinical context. Future work should explore how pressure data relates to ratings of fit and comfort, and how objective pressure data might be used to assist in clinical decision making.
30
Du, Jia-Xin, Yang-Hao Ma, Said Nawab e Yang-Chun Yong. "Simultaneous Electrochemical Detection of Cu2+ and Zn2+ in Pig Farm Wastewater". Sensors 24, n. 8 (12 aprile 2024): 2475. http://dx.doi.org/10.3390/s24082475.
Abstract (sommario):
In recent years, the rapid development of pig farming has led to a large quantity of heavy metal-polluted wastewater. Thus, it was desirable to develop a simple heavy metal detection method for fast monitoring of the wastewater from the pig farms. Therefore, there was an urgent need to develop a simple method for rapidly detecting heavy metal ions in pig farm wastewater. Herein, a simple electrochemical method for simultaneous detection of Cu2+ and Zn2+ was developed and applied to pig farm wastewater. With a glassy carbon electrode and anodic stripping voltammetry, simultaneous detection of Cu2+ and Zn2+ in water was achieved without the need for complicated electrode modification. Furthermore, it was found that the addition of Cd2+ can enhance the response current of the electrode to Zn2+, which increased the signal by eight times. After systematic optimization, the limit of detection (LOD) of 9.3 μg/L for Cu2+ and 45.3 μg/L for Zn2+ was obtained. Finally, it was successfully applied for the quantification of Cu2+ and Zn2+ with high accuracy in pig farm wastewater. This work provided a new and simple solution for fast monitoring of the wastewater from pig farms and demonstrated the potential of electrochemical measurement for application in modern animal husbandry.
31
Ritzert, Nicole L., Asha Rani, Tae-Jun Ko, Jeffrey J. Kim e Shin Ae Kim. "Multifunctional Periodontal Probes and Their Handheld Electronic System for Simultaneous Temperature, pH, and Depth Measurements". Journal of The Electrochemical Society 169, n. 2 (1 febbraio 2022): 027515. http://dx.doi.org/10.1149/1945-7111/ac50e4.
Abstract (sommario):
Microscale temperature and pH sensors, contained within an area of 125 μm × 750 μm, were fabricated on disposable 3D printed periodontal probe tips (0.5-mm diameter) with Marquis color-coded calibration marks using microfabrication and electrochemical methods. The probe tips were inserted in a reusable, wireless handheld electronic system that records the temperature and pH of specific oral sites such as a gingival sulcus. The linear response and precision of each sensor were tested in solutions of varying temperature and pH representing the physiological range of the oral cavity. The temperature and pH sensors showed linear response from 25 °C to 60 °C (±0.1 °C) and pH 4.0 to pH 8.0 (±0.1 pH unit), respectively. A calibration function performed by the system software increased precision between probes tenfold for temperature sensors (deviation range: 0.69 °C to –0.07 °C) and twofold for pH sensors (deviation range: 0.07 to 0.04). Wireless communication along with compatible software provides portability and facilitates chairside use. Simultaneous measurement of temperature and pH along with gingival sulcus depth may detect early signs of inflammation that current methods, such as probing and radiography, may not identify, thus minimizing potential tissue damage caused by periodontal disease.
32
Lützenkirchen, Johannes, Gopala Krishna Darbha, Venkata Sai Kiran Chakravadhanula, Engelbert Redel, Atiđa Selmani e Lionel Vayssières. "Interaction of Polyoxometalates and Nanoparticles with Collector Surfaces—Focus on the Use of Streaming Current Measurements at Flat Surfaces". Colloids and Interfaces 4, n. 3 (8 settembre 2020): 39. http://dx.doi.org/10.3390/colloids4030039.
Abstract (sommario):
Streaming current measurements were used to study the interaction of polyoxometalates (POMs) and nanoparticles (NPs) with flat surfaces as an alternative, innovative approach to infer POM and NP properties of potential sparse material in terms of charge and magnitude. With respect to POMs, the approach was able to reveal subtle details of charging properties of +7 vs. +8 charge at very low POM concentrations. For NPs, the sign of charge and even the zeta-potential curve was retrieved. Concerning NPs, mutual interaction between TiO2 and SiO2 surfaces was studied in some detail via macroscopic measurements. Post-mortem analysis of samples from electrokinetic studies and separate investigations via AFM and HRTEM verified the interactions between TiO2 NPs and SiO2 collector surfaces. The interactions in the SiO2/TiO2 system depend to some extent on NP morphology, but in all our systems, irreversible interactions were observed, which would make the studied types of NPs immobile in natural environments. Overall, we conclude that the measurement of streaming currents at flat surfaces is valuable (i) to study NP and POM collector surface interactions and (ii) to simultaneously collect NPs or POM (or other small mobile clusters) for further (structural, morphological or release) investigations.
33
Duan, Jun, Min Qin, Bin Ouyang, Wu Fang, Xin Li, Keding Lu, Ke Tang et al. "Development of an incoherent broadband cavity-enhanced absorption spectrometer for in situ measurements of HONO and NO<sub>2</sub>". Atmospheric Measurement Techniques 11, n. 7 (30 luglio 2018): 4531–43. http://dx.doi.org/10.5194/amt-11-4531-2018.
Abstract (sommario):
Abstract. Gaseous nitrous acid (HONO) is an important source of OH radicals in the troposphere. However, its source, especially that during daytime hours remains unclear. We present an instrument for simultaneous unambiguous measurements of HONO and NO2 with high time resolution based on incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS). To achieve robust performance and system stability under different environment conditions, the current IBBCEAS instrument has been developed with significant improvements in terms of efficient sampling as well as resistance against vibration and temperature change, and the IBBCEAS instrument also has low power consumption and a compact design that can be easily deployed on different platforms powered by a high-capacity lithium ion battery. The effective cavity length of the IBBCEAS was determined using the absorption of O2-O2 to account for the “shortening” effect caused by the mirror purge flows. The wall loss for HONO was estimated to be 2.0 % via a HONO standard generator. Measurement precisions (2σ) for HONO and NO2 are about 180 and 340 ppt in 30 s, respectively. A field inter-comparison was carried out at a rural suburban site in Wangdu, Hebei Province, China. The concentrations of HONO and NO2 measured by IBBCEAS were compared with a long optical path absorption photometer (LOPAP) and a NOx analyzer (Thermo Fisher Electron Model 42i), and the results showed very good agreement, with correlation coefficients (R2) of HONO and NO2 being ∼0.89 and ∼0.95, respectively; in addition, vehicle deployments were also tested to enable mobile measurements of HONO and NO2, demonstrating the promising potential of using IBBCEAS for in situ, sensitive, accurate and fast simultaneous measurements of HONO and NO2 in the future.
34
Mackenzie, Bryan, Anthony C. Illing e Matthias A. Hediger. "Transport model of the human Na+-coupled l-ascorbic acid (vitamin C) transporter SVCT1". American Journal of Physiology-Cell Physiology 294, n. 2 (febbraio 2008): C451—C459. http://dx.doi.org/10.1152/ajpcell.00439.2007.
Abstract (sommario):
Vitamin C (l-ascorbic acid) is an essential micronutrient that serves as an antioxidant and as a cofactor in many enzymatic reactions. Intestinal absorption and renal reabsorption of the vitamin is mediated by the epithelial apical l-ascorbic acid cotransporter SVCT1 (SLC23A1). We explored the molecular mechanisms of SVCT1-mediated l-ascorbic acid transport using radiotracer and voltage-clamp techniques in RNA-injected Xenopus oocytes. l-Ascorbic acid transport was saturable ( K0.5 ≈ 70 μM), temperature dependent ( Q10 ≈ 5), and energized by the Na+ electrochemical potential gradient. We obtained a Na+-l-ascorbic acid coupling ratio of 2:1 from simultaneous measurement of currents and fluxes. l-Ascorbic acid and Na+ saturation kinetics as a function of cosubstrate concentrations revealed a simultaneous transport mechanism in which binding is ordered Na+, l-ascorbic acid, Na+. In the absence of l-ascorbic acid, SVCT1 mediated pre-steady-state currents that decayed with time constants 3–15 ms. Transients were described by single Boltzmann distributions. At 100 mM Na+, maximal charge translocation ( Qmax) was ≈25 nC, around a midpoint ( V0.5) at −9 mV, and with apparent valence ≈−1. Qmax was conserved upon progressive removal of Na+, whereas V0.5 shifted to more hyperpolarized potentials. Model simulation predicted that the pre-steady-state current predominantly results from an ion-well effect on binding of the first Na+ partway within the membrane electric field. We present a transport model for SVCT1 that will provide a framework for investigating the impact of specific mutations and polymorphisms in SLC23A1 and help us better understand the contribution of SVCT1 to vitamin C metabolism in health and disease.
35
Bouhram, M., N. Dubouloz, M. Hamelin, S. A. Grigoriev, M. Malingre, K. Torkar, M. V. Veselov et al. "Electrostatic interaction between Interball-2 and the ambient plasma. 1. Determination of the spacecraft potential from current calculations". Annales Geophysicae 20, n. 3 (31 marzo 2002): 365–76. http://dx.doi.org/10.5194/angeo-20-365-2002.
Abstract (sommario):
Abstract. The Interball-2 spacecraft travels at altitudes extending up to 20 000 km, and becomes positively charged due to the low-plasma densities encountered and the photoemission on its sunlit surface. Therefore, a knowledge of the spacecraft potential Fs is required for correcting accurately thermal ion measurements on Interball-2. The determination of Fs is based on the balance of currents between escaping photoelectrons and incoming plasma electrons. A three-dimensional model of the potential structure surrounding Interball-2, including a realistic geometry and neglecting the space-charge densities, is used to find, through particle simulations, current-voltage relations of impacting plasma electrons Ie (Fs ) and escaping photoelectrons Iph (Fs ). The inferred relations are compared to analytic relationships in order to quantify the effects of the spacecraft geometry, the ambient magnetic field B0 and the electron temperature Te . We found that the complex geometry has a weak effect on the inferred currents, while the presence of B0 tends to decrease their values. Providing that the photoemission saturation current density Jph0 is known, a relation between Fs and the plasma density Ne can be derived by using the current balance. Since Jph0 is critical to this process, simultaneous measurements of Ne from Z-mode observations in the plasmapause, and data on the potential difference Fs - Fp between the spacecraft and an electric probe (p) are used in order to reverse the process. A value Jph0 ~ = 32 µAm-2 is estimated, close to laboratory tests, but less than typical measurements in space. Using this value, Ne and Fs can be derived systematically from electric field measurements without any additional calculation. These values are needed for correcting the distributions of low-energy ions measured by the Hyperboloid experiment on Interball-2. The effects of the potential structure on ion trajectories reaching Hyperboloid are discussed quantitatively in a companion paper.Key words. Space plasma physics (charged particle motion and acceleration; numerical simulation studies; spacecraft sheaths, wakes, charging)
36
Song, J., e M. J. Davis. "Chloride and cation currents activated by bradykinin in coronary venular endothelial cells". American Journal of Physiology-Heart and Circulatory Physiology 267, n. 6 (1 dicembre 1994): H2508—H2515. http://dx.doi.org/10.1152/ajpheart.1994.267.6.h2508.
Abstract (sommario):
Bradykinin (BK) is known to activate several types of ion channels in endothelial cells, including a K+ channel and a nonselective cation channel. The predominant BK-activated current in most endothelial cells appears to be an outward, Ca(2+)-activated K+ current. We consistently recorded a rapidly activated, spontaneously inactivated inward current stimulated by BK in bovine coronary venular endothelial cells (CVECs). With the use of a whole cell, perforated patch recording mode, the average magnitude of the current was -293 +/- 38 pA. Simultaneous measurements of current and intracellular Ca2+ concentration ([Ca2+]i) showed that the inward current correlated closely with transient increases in [Ca2+]i due to Ca2+ release from intracellular stores. The current could be blocked by 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS) but not by La3+, and it persisted in Ca(2+)-free/Na(+)-free solution. When intra- and/or extracellular Cl- concentrations were altered, the reversal potential of the current shifted according to the calculated Cl- -equilibrium potential, indicating that the current was carried primarily by Cl-. Another inward current was also activated by BK. This current was slower to activate, could be blocked by La3+, but was not blocked by DIDS. The time course of the slowly activated current correlated with the plateau phase of the BK-stimulated [Ca2+]i increase, which was similar to the behavior of a nonselective cation current reported previously. We propose that these two currents may contribute to the depolarizations and net inward currents induced by BK in this cell line.
37
Martin, S. C., J. Thompson e T. J. Shuttleworth. "Potentiation of Ca(2+)-activated secretory activity by a cAMP-mediated mechanism in avian salt gland cells". American Journal of Physiology-Cell Physiology 267, n. 1 (1 luglio 1994): C255—C265. http://dx.doi.org/10.1152/ajpcell.1994.267.1.c255.
Abstract (sommario):
In the avian salt gland carbachol (CCh) evokes oscillations in K+ and Cl- current that are sufficient to fully activate secretory activity. Employing the perforated patch-clamp technique, we demonstrate that beta-adrenergic receptor activation stimulates a sustained adenosine 3',5'-cyclic monophosphate (cAMP)-dependent Cl- current with no increase in K+ current. This evokes only a modest increase in secretory activity. However, application of isoproterenol in the presence of a threshold dose of CCh results in maximal secretory activity. Membrane potential measurements demonstrate that isoproterenol stimulates a sustained membrane depolarization from approximately -45 mV to the Cl- equilibrium potential (ECl), whereas CCh evokes oscillations in membrane potential to levels more negative than ECl, representing a mixture of K+ and Cl- conductances. We conclude that, in agreement with current models of fluid secretion, maximal stimulation can only be achieved with simultaneous activation of both K+ and Cl- currents. Because isoproterenol fails to stimulate a K+ current, Cl- secretion is reduced as the driving force for Cl- secretion is dissipated. However, if a driving force is imposed by increasing K+ channel activity (by coadministering CCh), Cl- efflux is sustained. These results could provide a basis for the marked potentiation of Ca(2+)-mediated secretion by agonists that increase cAMP seen in in vivo studies of salivary glands and other exocrine tissues.
38
Yu, Xiao, Xiao-Wei Chen, Peng Zhou, Lijun Yao, Tao Liu, Bo Zhang, Ying Li et al. "Calcium influx through If channels in rat ventricular myocytes". American Journal of Physiology-Cell Physiology 292, n. 3 (marzo 2007): C1147—C1155. http://dx.doi.org/10.1152/ajpcell.00598.2005.
Abstract (sommario):
The hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, or cardiac ( If)/neuronal ( Ih) time- and voltage-dependent inward cation current channels, are conventionally considered as monovalent-selective channels. Recently we discovered that calcium ions can permeate through HCN4 and Ih channels in neurons. This raises the possibility of Ca2+ permeation in If, the Ih counterpart in cardiac myocytes, because of their structural homology. We performed simultaneous measurement of fura-2 Ca2+ signals and whole cell currents produced by HCN2 and HCN4 channels (the 2 cardiac isoforms present in ventricles) expressed in HEK293 cells and by If in rat ventricular myocytes. We observed Ca2+ influx when HCN/ If channels were activated. Ca2+ influx was increased with stronger hyperpolarization or longer pulse duration. Cesium, an If channel blocker, inhibited If and Ca2+ influx at the same time. Quantitative analysis revealed that Ca2+ flux contributed to ∼0.5% of current produced by the HCN2 channel or If. The associated increase in Ca2+ influx was also observed in spontaneously hypertensive rat (SHR) myocytes in which If current density is higher than that of normotensive rat ventricle. In the absence of EGTA (a Ca2+ chelator), preactivation of If channels significantly reduced the action potential duration, and the effect was blocked by another selective If channel blocker, ZD-7288. In the presence of EGTA, however, preactivation of If channels had no effects on action potential duration. Our data extend our previous discovery of Ca2+ influx in Ih channels in neurons to If channels in cardiac myocytes.
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Brimaud, Sylvain, Zenonas Jusys e R. Jürgen Behm. "Shape-selected nanocrystals for in situ spectro-electrochemistry studies on structurally well defined surfaces under controlled electrolyte transport: A combined in situ ATR-FTIR/online DEMS investigation of CO electrooxidation on Pt". Beilstein Journal of Nanotechnology 5 (28 maggio 2014): 735–46. http://dx.doi.org/10.3762/bjnano.5.86.
Abstract (sommario):
The suitability and potential of shape selected nanocrystals for in situ spectro-electrochemical and in particular spectro-electrocatalytic studies on structurally well defined electrodes under enforced and controlled electrolyte mass transport will be demonstrated, using Pt nanocrystals prepared by colloidal synthesis procedures and a flow cell set-up allowing simultaneous measurements of the Faradaic current, FTIR spectroscopy of adsorbed reaction intermediates and side products in an attenuated total reflection configuration (ATR-FTIRS) and differential electrochemical mass spectrometry (DEMS) measurements of volatile reaction products. Batches of shape-selected Pt nanocrystals with different shapes and hence different surface structures were prepared and structurally characterized by transmission electron microscopy (TEM) and electrochemical methods. The potential for in situ spectro-electrocatalytic studies is illustrated for COad oxidation on Pt nanocrystal surfaces, where we could separate contributions from two processes occurring simultaneously, oxidative COad removal and re-adsorption of (bi)sulfate anions, and reveal a distinct structure sensitivity in these processes and also in the structural implications of (bi)sulfate re-adsorption on the CO adlayer.
40
Mckay, P., e D. B. Mitton. "An Electrochemical Investigation of Localized Corrosion on Titanium in Chloride Environments". Corrosion 41, n. 1 (1 gennaio 1985): 52–62. http://dx.doi.org/10.5006/1.3581969.
Abstract (sommario):
Abstract Electrochemical methods have been used to study the crevice and pitting corrosion behavior of unalloyed titanium in chloride solutions at elevated temperatures (maximum 150 C). The investigation was focused primarily on crevice corrosion. The techniques which were used included simultaneous measurement of the corrosion potential-time behavior of plain and creviced specimens, controlled anodic polarization of creviced specimens (both potentiostatic and potentiodynamic methods), and the measurement of the current and the potential of galvanic cells formed between creviced specimens and large uncreviced areas of titanium. The data obtained under both controlled and freely corroding conditions were interpreted using an electrochemical mechanism of crevice corrosion on titanium in chloride solutions. The degree of anodic polarization in the crevice, produced either potentiostatically or naturally by galvanic coupling, was shown to have a major effect on the kinetics of crevice corrosion initiation and propagation. The distribution of the cathodic reaction between reduction of O2 on the external surface and H+ reduction in the crevice was evaluated. The concept of a critical crevice pH for initiation of crevice corrosion was used to explain the differences between these results and those of other published studies for the critical temperatures and chloride concentrations necessary for initiation of crevice corrosion on unalloyed titanium.
41
Zhang, Jingqing, Yong Shang, Xuehang Li, Yali Dong e Yanling Pei. "A Novel Technique for Full-Field Deformation and Temperature Measurement by Ultraviolet Imaging: Experimental Design and Preliminary Results". Coatings 11, n. 6 (27 maggio 2021): 641. http://dx.doi.org/10.3390/coatings11060641.
Abstract (sommario):
Synchronous measurement of full-field temperature and deformation at high temperature especially more than 1273 K is of much significance especially for part applications of turbine structures and materials. Non-contact optical methods attract more and more attention, however, current methods all face different challenges, such as strong light reflection on the surface of the specimen, disturbing radiation from environment, complex equipment setup, limited measured temperature not higher than 900 ℃ and so on. In this work, we develop an innovative technique to overcome some current problems. The measurement system employing an ultraviolet (UV) imaging system is composed of a scientific complementary metal oxide semiconductor (sCMOS) camera, a lens and a UV bandpass filter. The UV bandpass filter was used for thermal radiation elimination to acquire high quality images at elevated temperatures for deformation field calculation suitable for digital image correlation (DIC) method. The UV sensitive sCMOS camera without using active illumination was employed to collect enough UV radiation energy and eliminate the interference of the external ambient light, which is applicable for high accuracy temperature field measurement. Our system can realize the synchronous capture of image and temperature acquisition with passive UV imaging system at temperature not lower than 1473K. The feasibility of the method was verified through heating molybdenum (Mo) and Ni-based superalloy IC21 materials. The temperature fields of Mo measured by the established imaging system up to 1835 K with error less than 0.25% showed the effectiveness for temperature measurement. The estimated deformation and temperature field of Ni-based superalloy IC21 up to 1473 K with measured temperature error less than 0.5% demonstrated well the great potential of the UV imaging system in simultaneous measurement of temperature and deformation fields at elevated temperatures.
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Sugasawa, M., C. Erostegui, C. Blanchet e D. Dulon. "ATP activates a cation conductance and Ca(2+)-dependent Cl- conductance in Hensen cells of guinea pig cochlea". American Journal of Physiology-Cell Physiology 271, n. 6 (1 dicembre 1996): C1817—C1827. http://dx.doi.org/10.1152/ajpcell.1996.271.6.c1817.
Abstract (sommario):
Simultaneous whole cell patch-clamp and indo 1 fluorescence measurements were used to characterize ATP-evoked membrane currents and intracellular Ca2+ concentration ([Ca2+]i) changes in isolated Hensen cells of the guinea pig organ of Corti. At negative holding potential, ATP activated a biphasic inward current and a concomitant increase in [Ca2+]i. The initial current activated within < 50 ms, showed a reversal potential near 0 mV and was reversibly inhibited by 30 microM suramin, suggesting this conductance was mediated by ATP-gated nonselective cation channels. The delayed ATP-activated current was mainly carried by Cl- as indicated by its shift in reversal potential when intracellular Cl- was replaced by gluconate. This Cl- conductance appeared to be Ca(2+)-activated secondarily to Ca2+ influx, since it required the presence of extracellular Ca2+ and was suppressed when an intracellular solution containing 10 mM 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid was used. In the absence of extracellular Ca2+, ATP still increased [Ca2+]i concomitant with a monophasic inward cation current, indicating Ca2+ release from intracellular stores. We conclude that Hensen cells have ionotropic and metabotropic P2 purinoceptors. They also have Ca(2+)-activated Cl- channels that can be activated by extracellular ATP, suggesting that purinoceptors in Hensen cells could play a regulatory role in ion and water balance of cochlear fluids.
43
Tse, Chui, Li Zhang, Komal Dahya, Fidelia Pokuah, Otoe Sugahara, Uliana Danilenko e Hubert Vesper. "ODP179 Development of Derivatization-free ID-LC/MS/MS Method for Simultaneous Measurement of Human Serum Monosaccharides". Journal of the Endocrine Society 6, Supplement_1 (1 novembre 2022): A305. http://dx.doi.org/10.1210/jendso/bvac150.631.
Abstract (sommario):
Abstract According to the CDC's National Diabetes Statistics Report for 2020, it is estimated that 34.2 million, 10.5% of the U. S. population, have diabetes. High fructose intake has also been associated with increased de novo lipogenesis in the liver leading to non-alcoholic fatty liver disease (NAFLD). Emerging evidence suggests that measuring fructose, galactose, and other saccharides in addition to glucose may be helpful for diagnosis of metabolic disorders and other diseases. Therefore, there is a need for an accurate and precise laboratory method for measuring serum monosaccharide panels. Traditional monosaccharide assays used in patient care often can only quantitate one monosaccharide at a time. We aim to develop a high-throughput analytical method for simultaneous measurement of serum monosaccharides that is suitable for large scale epidemiologic studies. Our assay is based on a derivatization-free ID-LC/MS/MS procedure. Certified primary reference materials of monosaccharides from NIST (Gaithersburg, MD) were used for assay calibration. The serum samples were spiked with 13 C labeled internal standards. The monosaccharides were isolated from serum matrix by acetonitrile protein precipitation and filtration in 96-well filter plate (0.2um, porous PTFE). Aliquot of the acetonitrile filtrate was applied on an AB SCIEX Triple Quad™ 6500 LC/MS/MS system for analysis. The monosaccharides including glucose, galactose, fructose, mannose, and potential interferences were resolved from each other on Unison UK Amino column (3×250mm) eluted with acetonitrile and water gradient. Selective reaction monitoring in negative electrospray ionization mode was used for quantitation of monosaccharides in the samples. The measurement ranges covered 10–402 mg/dL for glucose, which is sufficient to monitor the serum glucose levels in normal, hypo-, and hyperglycemia patient samples. Using 4 levels of NIST SRM 965b (values assigned using GC-MS based reference measurement procedure), the method demonstrated excellent measurement accuracy of over 98% for serum glucose. The imprecision of serum glucose measurement was within 3%. Imprecision and accuracy of lower abundant serum monosaccharides were lower than 6% and above 96%, respectively. The application of 96-well format filter plate and automated liquid handler system significantly improves the throughput of sample preparation. The current analytical method can be used to simultaneously measure the concentrations levels of a panel of serum monosaccharides with appropriate accuracy and precision. Free of derivatization, simple sample procedure and application of automation system significantly improves throughput of the assay which are suitable for routine serum monosaccharides assay in clinical laboratories and for large biomonitoring studies. Presentation: No date and time listed
44
McGlade, James, Luke Wallace, Karin Reinke e Simon Jones. "The Potential of Low-Cost 3D Imaging Technologies for Forestry Applications: Setting a Research Agenda for Low-Cost Remote Sensing Inventory Tasks". Forests 13, n. 2 (28 gennaio 2022): 204. http://dx.doi.org/10.3390/f13020204.
Abstract (sommario):
Limitations with benchmark light detection and ranging (LiDAR) technologies in forestry have prompted the exploration of handheld or wearable low-cost 3D sensors (<2000 USD). These sensors are now being integrated into consumer devices, such as the Apple iPad Pro 2020. This study was aimed at determining future research recommendations to promote the adoption of terrestrial low-cost technologies within forest measurement tasks. We reviewed the current literature surrounding the application of low-cost 3D remote sensing (RS) technologies. We also surveyed forestry professionals to determine what inventory metrics were considered important and/or difficult to capture using conventional methods. The current research focus regarding inventory metrics captured by low-cost sensors aligns with the metrics identified as important by survey respondents. Based on the literature review and survey, a suite of research directions are proposed to democratise the access to and development of low-cost 3D for forestry: (1) the development of methods for integrating standalone colour and depth (RGB-D) sensors into handheld or wearable devices; (2) the development of a sensor-agnostic method for determining the optimal capture procedures with low-cost RS technologies in forestry settings; (3) the development of simultaneous localisation and mapping (SLAM) algorithms designed for forestry environments; and (4) the exploration of plot-scale forestry captures that utilise low-cost devices at both terrestrial and airborne scales.
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Manning, Philip, e Calum J. McNeil. "Electrochemical and optical sensing of reactive oxygen species: pathway to an integrated intracellular and extracellular measurement platform". Biochemical Society Transactions 39, n. 5 (21 settembre 2011): 1288–92. http://dx.doi.org/10.1042/bst0391288.
Abstract (sommario):
A comprehensive understanding of ROS (reactive oxygen species)-dependent cellular interaction requires the previously unmet ability to simultaneously monitor the intra- and extra-cellular environments. The present review assesses the potential of novel electrochemical and fluorescent-based nanosensor approaches to address the limitations of existing techniques for ROS analysis. Data generated by these new approaches have already contributed significantly to current understanding of the roles that these species play in various in vitro scenarios. However, integration of these novel approaches has the potential to offer, for the first time, the unparalleled ability to measure simultaneously and in real-time ROS flux in both the intra- and extra-cellular environments.
46
Kurita, Koichi. "A Non-Contact and Real-Time Measurement Technique of Human Body Potential Using Electrostatic Induction Current Accompanied by Human Body Motion". Sensors 22, n. 19 (21 settembre 2022): 7161. http://dx.doi.org/10.3390/s22197161.
Abstract (sommario):
This paper describes a non-contact and real-time measurement technique of human body potential using ultra-sensitive electrostatic induction. When a participant moves his/her palm to a position approximately 30 cm away from an electrostatic induction sensor, electrostatic induction current flows transiently. It is clarified whether estimation of the human body potential is possible by simultaneously measuring the velocity of the participant’s palm and distance between the participant’s palm and sensor. In addition, even when the participant walks at a position approximately 50 cm away from the electrostatic induction sensor, it is confirmed that the estimation of human body potential is possible.
47
Chen, Taicong, e Zhou Zhou. "An Improved Vision Method for Robust Monitoring of Multi-Point Dynamic Displacements with Smartphones in an Interference Environment". Sensors 20, n. 20 (20 ottobre 2020): 5929. http://dx.doi.org/10.3390/s20205929.
Abstract (sommario):
Current research on dynamic displacement measurement based on computer vision mostly requires professional high-speed cameras and an ideal shooting environment to ensure the performance and accuracy of the analysis. However, the high cost of the camera and strict requirements of sharp image contrast and stable environment during the shooting process limit the broad application of the technology. This paper proposes an improved vision method to implement multi-point dynamic displacement measurements with smartphones in an interference environment. A motion-enhanced spatio-temporal context (MSTC) algorithm is developed and applied together with the optical flow (OF) algorithm to realize a simultaneous tracking and dynamic displacement extraction of multiple points on a vibrating structure in the interference environment. Finally, a sine-sweep vibration experiment on a cantilever sphere model is presented to validate the feasibility of the proposed method in a wide-band frequency range. In the test, a smartphone was used to shoot the vibration process of the sine-sweep-excited sphere, and illumination change, fog interference, and camera jitter were artificially simulated to represent the interference environment. The results of the proposed method are compared to conventional displacement sensor data and current vision method results. It is demonstrated that, in an interference environment, (1) the OF method is prone to mismatch the feature points and leads to data deviated or lost; (2) the conventional STC method is sensitive to target selection and can effectively track those targets having a large proportion of pixels in the context with motion tendency similar to the target center; (3) the proposed MSTC method, however, can ease the sensitivity to target selection through in-depth processing of the information in the context and finally enhance the robustness of the target tracking. In addition, the MSTC method takes less than one second to track each target between adjacent frame images, implying a potential for online measurement.
48
Schumacher, Sandra, e Werner Gräsle. "Challenges for geomechanical laboratory analyses of claystones with regard to the time frame of the site selection process". Safety of Nuclear Waste Disposal 2 (6 settembre 2023): 75. http://dx.doi.org/10.5194/sand-2-75-2023.
Abstract (sommario):
Abstract. The current programme for the site selection process in Germany schedules 11 months for geomechanical laboratory tests per potential future site (BGE, 2022). For the laboratory analysis of rock salt, this time frame seems realistic as no hydromechanical coupling has to be taken into account. In the case of a crystalline basement, the intact rock matrix is low permeable, but transport processes are dominated by ubiquitous fracture networks, which are hard to capture in laboratory settings. Thus, the effect that hydromechanical coupling in low permeable rock has on the speed of laboratory measurements will probably be no problem. However, for claystones, the geomechanical processes within the rock matrix strongly depend on the hydromechanical coupling, which thus determines the speed with which, for example, loading ramps can be applied in the laboratory. The need to maintain the pore pressure equilibrium during the experiments in order to know the acting effective stresses slows down the speed of the measurements significantly. Given the tight time frame of 11 months and the numerous parameters which have to be analysed according to law (StandAG, 2017), the low speed with which the experiments can be performed represents a severe hindrance. It is thus important to establish measurement protocols which enable the simultaneous determination of several parameters in order to save time. Based on our experience with experiments on Opalinus Clay, we offer a first idea of how such a measurement protocol could look and would like to invite a discussion on how to optimise experiments on claystones further in order to have a chance to meet the very tight time frame required by the site selection process.
49
Harrison, R. G., e A. J. Bennett. "Multi-station synthesis of early twentieth century surface atmospheric electricity measurements for upper tropospheric properties". Advances in Geosciences 13 (30 luglio 2007): 17–23. http://dx.doi.org/10.5194/adgeo-13-17-2007.
Abstract (sommario):
Abstract. The vertical columnar current density in the global atmospheric electrical circuit depends on the local columnar resistance. A simple model for the columnar resistance is suggested, which separates the local boundary layer component from the upper troposphere cosmic ray component, and calculates the boundary layer component from a surface measurement of air conductivity. This theory is shown to provide reasonable agreement with observations. One application of the simple columnar model theory is to provide a basis for the synthesis of surface atmospheric electrical measurements made simultaneously at several European sites. Assuming the ionospheric potential to be common above all the sites, the theoretical air-earth current density present in the absence of a boundary layer columnar resistance can be found by extrapolation. This is denoted the free troposphere limit air-earth current density, J0. Using early surface data from 1909 when no ionospheric potential data are available for corroboration, J0 is found to be ~6 pA m−2, although this is subject to uncertainties in the data and limitations in the theory. Later (1966–1971) European balloon and surface data give J0=2.4 pA m−2.
50
Wendt, Eric A., Casey Quinn, Christian L'Orange, Daniel D. Miller-Lionberg, Bonne Ford, Jeffrey R. Pierce, John Mehaffy et al. "A low-cost monitor for simultaneous measurement of fine particulate matter and aerosol optical depth – Part 3: Automation and design improvements". Atmospheric Measurement Techniques 14, n. 9 (15 settembre 2021): 6023–38. http://dx.doi.org/10.5194/amt-14-6023-2021.
Abstract (sommario):
Abstract. Atmospheric particulate matter smaller than 2.5 µm in diameter (PM2.5) has a negative impact on public health, the environment, and Earth's climate. Consequently, a need exists for accurate, distributed measurements of surface-level PM2.5 concentrations at a global scale. Existing PM2.5 measurement infrastructure provides broad PM2.5 sampling coverage but does not adequately characterize community-level air pollution at high temporal resolution. This motivates the development of low-cost sensors which can be more practically deployed in spatial and temporal configurations currently lacking proper characterization. Wendt et al. (2019) described the development and validation of a first-generation device for low-cost measurement of AOD and PM2.5: the Aerosol Mass and Optical Depth (AMODv1) sampler. Ford et al. (2019) describe a citizen-science field deployment of the AMODv1 device. In this paper, we present an updated version of the AMOD, known as AMODv2, featuring design improvements and extended validation to address the limitations of the AMODv1 work. The AMODv2 measures AOD and PM2.5 at 20 min time intervals. The sampler includes a motorized Sun tracking system alongside a set of four optically filtered photodiodes for semicontinuous, multiwavelength (current version at 440, 500, 675, and 870 nm) AOD sampling. Also included are a Plantower PMS5003 sensor for time-resolved optical PM2.5 measurements and a pump/cyclone system for time-integrated gravimetric filter measurements of particle mass and composition. AMODv2 samples are configured using a smartphone application, and sample data are made available via data streaming to a companion website (https://csu-ceams.com/, last access: 16 July 2021). We present the results of a 9 d AOD validation campaign where AMODv2 units were co-located with an AERONET (Aerosol Robotics Network) instrument as the reference method at AOD levels ranging from 0.02 ± 0.01 to 1.59 ± 0.01. We observed close agreement between AMODv2s and the reference instrument with mean absolute errors of 0.04, 0.06, 0.03, and 0.03 AOD units at 440, 500, 675, and 870 nm, respectively. We derived empirical relationships relating the reference AOD level to AMODv2 instrument error and found that the mean absolute error in the AMODv2 deviated by less than 0.01 AOD units between clear days and elevated-AOD days and across all wavelengths. We identified bias from individual units, particularly due to calibration drift, as the primary source of error between AMODv2s and reference units. In a test of 15-month calibration stability performed on 16 AMOD units, we observed median changes to calibration constant values of −7.14 %, −9.64 %, −0.75 %, and −2.80 % at 440, 500, 675, and 870 nm, respectively. We propose annual recalibration to mitigate potential errors from calibration drift. We conducted a trial deployment to assess the reliability and mechanical robustness of AMODv2 units. We found that 75 % of attempted samples were successfully completed in rooftop laboratory testing. We identify several failure modes in the laboratory testing and describe design changes that we have since implemented to reduce failures. We demonstrate that the AMODv2 is an accurate, stable, and low-cost platform for air pollution measurement. We describe how the AMODv2 can be implemented in spatial citizen-science networks where reference-grade sensors are economically impractical and low-cost sensors lack accuracy and stability.