Sensor Probe Research Articles

P-309 High-viscosity oil overlay provides less protection against media evaporation in extended dry incubation conditions compared with conventional light oil but a reduced heat loss

Abstract Study question Does high-viscosity oil (HVO) improve stability on osmolality, temperature, pH, Na+ concentration, and mouse embryo development compared with conventional light oil (CLO)? Summary answer In dry incubation condition, osmolality and Na+ concentration were significantly higher in embryo culture media overlaid with either oils, but HVO was worst than CLO. What is known already Suboptimal in-vitro culture conditions affect embryo quality and viability. Overlaying culture media with oil is used to maintain a stable optimal culture environment, including reduction of evaporation. Despite dry incubators are known to increase evaporation, they have become more common, especially with the widespread use of time-lapse imaging. The risk of excessive evaporation with the consequent impact on osmolality is even more significant with the promoted usage of undisturbed extended embryo culturing. Novel products (HVO) therefore been developed and recently commercialised with the aim of reducing such effect. Nonetheless, no independent data are available to determine their superiority over CLO. Study design, size, duration Culture media dishes overlaid with CLO or HVO were incubated in dry and humidified conditions while mimicking extended culture conditions in four independent experimental groups. Changes in osmolality, pH and Na+ concentrations over three days were measured. Lipid peroxidation and mouse embryo development were recorded to assess toxicity. Additionally, the ability of different oils to maintain the temperature in the culture drops when culture dishes were removed from the incubator was compared. Participants/materials, setting, methods Standard embryo culture media drops overlayered with HVO or CLO were incubated in two equally calibrated, identical incubators providing dry or humid conditions. Osmolality (Day1, D3, D5 measured by freezing-point depression osmometer), temperature drop rate at room temperature (T-type thermocouple sensor probe), pH and [Na+] (hand-held blood gas analyser), mouse embryo assay (MEA, 75 embryos from naturally mated CD1 female mice (N = 5), and lipid peroxidation end-product levels (MDA, TBARS assay) were compared among groups. Main results and the role of chance The osmolality of the media incubated in humidified conditions did not show a significant change throughout the 5-day experiment, regardless of the type of oil used. However, in dry conditions, a significant daily increase in osmolality was evident; changes were more prominent under HVO (D1, 278.13 ± 0.82; D3, 286.00 ± 1.51; D5 289.86 ± 1.17 mOsm/kg H2O ± SEM. p ≤ 0.001). The osmolality of the media overlaid by the same type of oil raised between different incubators, and reached a significantly higher value on D5. [Na+] values were consistent with the osmolality changes. The recovery time of the temperature on the heated stage to 37 °C was similar in CLO- and HLO-overlaid media (1:07 ± 1:02 min and 2:00 ± 0.7 min, respectively). The temperature drop rate after media were kept at ambient temperature was similar in the first 4 min. By the end, the temperature difference reached a significance between CLO and HVO overlays (32.4 ± 0.4 °C and 32.7 ± 0.4 °C respectively, p = 0.045). No significant differences were found in pH, lipid peroxidation or mouse embryo development between the study experimental groups. Limitations, reasons for caution The embryos for MEA were obtained without hyperstimulation, resulting in a small sample size for the study. The exact timing of fertilisation was impossible to detect after mice mating, which caused inconsistency in embryo grading. Wider implications of the findings Dry incubators may determine suboptimal embryo culture conditions. A newly developed heavy oil proved to be inferior to conventional light oil in maintaining osmolality stable. Further research should be carried out in engineering systems that limit culture media evaporation or support undisturbed embryo culture in humidified conditions. Trial registration number not applicable

Toward Improvements in Pressure Measurements for Near Free-Field Blast Experiments

This paper proposes two ways to improve pressure measurement in air-blast experimentations, mostly for close-in detonations defined by a small-scaled distance below 0.4 m.kg−1/3. Firstly, a new kind of custom-made pressure probe sensor is presented. The transducer is a piezoelectric commercial, but the tip material has been modified. The dynamic response of this prototype is established in terms of time and frequency responses, both in a laboratory environment, on a shock tube, and in free-field experiments. The experimental results show that the modified probe can meet the measurement requirements of high-frequency pressure signals. Secondly, this paper presents the initial results of a deconvolution method, using the pencil probe transfer function determination with a shock tube. We demonstrate the method on experimental results and draw conclusions and prospects.

Quality Assessment and Monitoring of River Water Using IoT Infrastructure

The quality assessment of water is a challenging task due to extensive experimental requirements. However, the process of water quality monitoring can be automated with the help of Internet of Things (IoT) devices using sensor probes. This paper presents the IoT infrastructure-based river water quality monitoring and assessment. Experiments were performed to assess the water quality during different months and seasons for the Ganga river and Sangam (confluence of Ganga and Yamuna rivers) at Prayagraj, Uttar Pradesh, India. The data samples were collected for 15 months continuously using the Libelium smart water kit. The Smart Water IoT (SWIoT) kit was equipped with sensors to assess specific parameters like pH, dissolved oxygen, temperature, conductivity, and oxidation-reduction potential. An algorithm is also presented that harnesses PCA and factor analysis for feature selection and weight assignment for river water quality assessment. Further water quality is quantified using the water quality index that helps to categorize the water quality for different usages. The results corroborate that the water quality of the Ganga River was found to be better than the Sangam site most of the time, owing to the higher level of pollution in Yamuna River. Additionally, the water quality of both rivers were found to be suitable for irrigation and fisheries but not for drinking purposes, considering the average oxygen levels.

Synthesis of N-acylated pyrazolines: Spectroscopic, crystallographic, Hirshfeld Surface, lead sensing and theoretical studies

N-Acylated-2-pyrazolines (NA2Pyr) were synthesized from chalcone and hydrazine hydrate under one pot cyclocondensation in the presence of propionic acid and trifluoroacetic acid respectively. The structures were determined using FT-IR, 1H NMR, 13C NMR spectral analyses, as well as single crystal diffraction study (Sc-XRD). An effective metal ion sensor (Lead ion) with a flat glassy carbon electrode (GCE) was produced for prospective use by coupling a conducting coating binder (PEDOT:PSS) with a thin-layer NA2Pyr modified electrode (NA2Pyr/GCE). Linear sweep voltammetry was used to detect lead (Pb2+) ions in phosphate aqueous phase. The sensitivity (11,867 uAnM−1cm−2) of the chemical sensor probe was measured utilizing the calibration curve slope and the adjusted electrode active surface area. The linear dynamic range (LDR: 0.01 nM to 10.0 mM) was computed using the calibration plot's maximal linearity line. The detection limit (0.008 nM) was calculated by including 3σ/m (where σ is the standard deviation of the blank response and m is the slope of the calibration curve). The novel electrochemical method is dependable and effective technique for detecting heavy metal ions as a selective lead-sensor for the protection of large-scale medical, biochemical, and environmental fields. Density functional theory (TD-DFT/B3LYP/6-311++G(d,p) was used to computed FMO computations and further study using the optimized geometric parameters of the ground state molecules. According to the predicted energies for HOMO and LUMO, in which the charge of molecule is conveyed, and MEP map, the chemically reactive zone suitable for drug action was identified. The Electron Localization Function (ELF), Non-Bonding Orbitals, Excitation Energies, AIM Charges, and Fukui Functions are also calculated. The docking study contributed to the analysis of EGFR protein binding.

Electrochemical Sensing of Amoxicillin Drug-Assisted Uropathogenic E. coli Bacteria Using Gold Nanostructures—A Preliminary Study

The present study focuses on the electrochemical sensing of amoxicillin (AMX, as a model antibiotic drug) and its interaction with Uropathogenic E. coli (UPEC) bacteria (as a model pathogen) under physiological conditions. The electrochemical sensor probe is formulated by nanostructured gold wires (AuNWs) embedded in a carbon nanofiber–chitosan (CNF-CHIT) matrix. The synthesis of AuNWs is characterized by scanning electron microscopy (SEM), UV-Visible spectrophotometry, and X-ray photoelectron spectroscopy (XPS). The CNF-CHIT/AuNW-modified system is characterized by SEM and XPS. Initially, the CNF-CHIT/AuNW electrode was utilized for the sensing of AMX; later, in the antibiotic drug-assisted sensing of UPEC, i.e., in the presence of AMX, the interaction of UPEC was studied. The modified electrode showed appreciable sensitivity for AMX sensing; also, the interaction of AMX with UPEC is studied at two different conditions. One, at a fixed concentration of AMX (100 µM) and different concentrations of UPEC bacteria (0.6–1.2 × 106 CFU/mL), and another with incubation time (1 h–1 h 35 min) for bacterial reaction. The electrochemical antimicrobial resistance developed by UPEC, which is inherent in the sensing of AMX, is the key concept for the detection of pathogens.

Recent Progress in Endoplasmic Reticulum-Targetable Small-Molecule Probes for Fluorescence Sensing and Phototherapy

Recent Progress in Endoplasmic Reticulum-Targetable Small-Molecule Probes for Fluorescence Sensing and Phototherapy

Differential electrochemical behaviour of phytofabricated and chemically synthesized silver nanoparticles towards hydrogen peroxide sensing**

AbstractSilver nanoparticles (AgNPs) are one of the most widely used nanomaterials for biomedical applications. However, the impact of its synthesis by chemical and plant‐mediated routes on its differential electrochemical behaviour has not been examined till date. Here, we report for the first time the differential study of the electrochemical behaviour of the AgNPs synthesized by different routes. First, the AgNPs were obtained by different routes (chemical and phytofabrication) and extensively characterized to compare their physical properties. Thereafter, a comparison of electron transfer kinetics between chemically synthesized (Ag−C) and phyto‐fabricated (Ag‐Phy) nanoparticles (NPs) has been studied by electrochemical techniques such as potentiodynamic cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). To further investigate the electrocatalytic properties of both types of AgNPs, we have used the peroxide moieties (H2O2), and the Ag−C NPs‐based sensor probe has been reported to have four times better sensitivity than the Ag−Phy NPs‐based sensor. The AgNPs modified sensor probes have also been tested in real‐world environments to explore the consistency of their performance in complex matrices by using clinical urine samples, where we found comparable sensitivity to the standard conditions.

Dual noncovalent interaction facilitated highly sensitive and specific colorimetric–fluorescent sensing for tryptamines

Tryptamines, an important family of new psychoactive substances, have attracted special attention from the international community owing to their abuse and corresponding influence on human health and social stabilization. However, realizing the on-site analysis of tryptamines with rapid and precise responses remains a great challenge, especially if these are present in their disguised form. A highly sensitive and specific analytical method was developed herein, driven by a dual noncovalent interaction towards tryptamines. An optical probe was designed to specifically recognize tryptamines via π–π stacking and hydrogen bond effect to produce significant optical responses for both colorimetric and fluorescent modes. The detection limits were calculated as 4.1 nM (fluorescent mode) and 17.2 μM (colorimetric mode), respectively, with an excellent specificity towards 16 interfering substances within 0.6 s. Based on the excellent detection performances of the proposed probe, a portable and operable sensor was developed and demonstrated with the rapid and accurate analysis capability towards the controlled α-methyl-tryptamine in complicated scenarios. We expect the portable sensor equipped with this optical probe would provide a powerful tool for trace tryptamine detection and effective technical support for real-time monitoring of other new psychoactive substances in complicated media.

Precise Electron-Withdrawing Strength Modulation of ESIPT Probes for Ultrasensitive and Specific Fluorescence Sensing.

The precise regulation of the electron-withdrawing/electron-donating strength in a probe is of great significance for the design of reaction-based fluorescent probes with specific functionalities. Here, a family of excited-state intramolecular proton transfer (ESIPT)-based probes with fluorescence turn-on sensing properties toward KMnO4 was designed by precisely modulating the electron-withdrawing strength of the substituents located at the para-position of the recognition group. It is found that -F, -CHO, and -H as the electron-withdrawing groups bound at the probe can specifically recognize KMnO4, which ensures a blue emission displayed by the reaction products. Especially with -CHO as the electron-withdrawing group, the reaction product shows the most stable fluorescence. The probe 2-(benzo[d]oxazol-2-yl)-4-formylphenyl acrylate (BOPA-CHO) demonstrated a more superior sensing performance toward KMnO4, including a low limit of detection (LOD, 0.96 nM), a rapid response (<3 s), and a rather good selectivity even in the presence of 21 interferents. Moreover, the practicality of the probe was further verified by a test pen comprising a BOPA-CHO-embedded sponge, which is capable of detecting KMnO4 solid with a naked-eye LOD of 11.62 ng. The present probe design and modulation strategy would open up a new path for the design of high-performance fluorescent probes.

Investigating the application of artificial hot and cold reference surfaces for improved ETc estimation using the UAS-METRIC energy balance model

The METRIC energy balance model requires the temperature of a hot (dry bare agricultural soil) and cold (fully transpiring crop) surfaces for the internal calibration and estimation of crop evapotranspiration (ETc). A previous study indicated that because of the limited field-of-view of UAS-based imagery, the application of unmanned aerial systems (UAS)-based METRIC could not guarantee the availability of representative hot and cold pixels in the field-of-view of the flight mission, even if the pixels were manually chosen. A study was conducted for two years (2017 and 2018) to evaluate the suitability of various artificial and portable hot (dry red mulch, dry terra cotta saucer plate, coconut fiber, wheat straw) and cold (surface of water, wet terra cotta saucer plate, green sponge, and white granite tile on top of polystyrene foam floating on water) artificial surfaces for use in the calibration of the UAS-METRIC model. The temperature of the surfaces was measured with a thermal infrared sensor mounted on a ground vehicle with a retractable mast (up to 7-m) facing downward to capture images at around the nadir hours (11 AM to 3 PM). The results showed that a green sponge floating in a water tray and a dry terra cotta saucer plate full of water best matched (rwet sponge= 0.93, rwet saucer =0.86) the temperature dynamics of fully irrigated short grass. Dry red mulch and a dry terra cotta saucer plate best matched (rdry red mulch= 0.98, rdry saucer =0.97) the temperature dynamics of bare and dry agricultural soil. These artificial hot and cold reference surfaces were then located within a field of view of nine different UAS flight missions over a spearmint field during the summer of 2021. Although the temperatures of the cold artificial surfaces correlated well with fully irrigated short grass planted near the spearmint field, they were 1.9–8.3 °C warmer than the taller spearmint crop canopy. The temperature of a dry red mulch/wet sponge and dry/wet terra cotta saucer plate used as artificial hot/cold anchor temperatures for ET estimation by the UAS-METRIC model resulted in overestimating the ETc obtained using field hot/cold pixels (dry bare soil/fully irrigated spearmint), or the ETc estimation based on a soil water balance measured by neutron probe and TEROS-10 sensors. The best hot/cold temperatures for internal calibration of the UAS-based imagery ET model are from dry soil and a fully irrigated canopy located in the field of view. In the absence of dry bare soil within the image, the use of dry red mulch is suggested. Additional research is needed to find artificial cold surfaces with temperatures closer to the temperature of fully irrigated canopies, which can be conveniently located for auto-selection within the images. In the meantime, for farm-scale applications, maintaining a field section guaranteed to be well irrigated is recommended.

Graphene-sensitized microring gas sensor probing with a single-wavelength laser

Graphene-sensitized microring gas sensor probing with a single-wavelength laser

On the Spatial Resolution of a Piezoresonance Probe Sensor with a Tungsten Needle

On the Spatial Resolution of a Piezoresonance Probe Sensor with a Tungsten Needle

A novel insight into the dual state emission mechanism of a new rofecoxib derivative and its multi-functional applications

There is growing interest in developing dual-state emission luminogens (DSEgens) in the fluorescent materials community due to their bright emission in both dilute solution and the solid state and potential applications in various areas. In this work, we have developed a new dual-state emission (DSE) luminogen by integrating a benzothiazolium unit into the rofecoxib skeleton, namely 5-((Z)-4-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)- amino)benzylidene)-rofecoxib (p-RBZ). Importantly, by combining theoretical calculations and experimental investigation, a novel insight into the DSE mechanism of p-RBZ is firstly proposed. The reduced density gradient (RDG) calculation and single X-ray data analysis, both revealed that p-RBZ had strong intramolecular π-π interaction between a ring and d ring, which can limit molecular rotation, reduce the rate of non-radiative transition, and enhance luminous efficiency in solution. Meanwhile, the conformation twist of p-RBZ and the highly restricted intermolecular π-π stacking may permit their bright emission in the solid state from the single-crystal X-ray and Hirshfeld surface analysis. Furthermore, p-RBZ displayed apparent solvatochromism, mechanochromism, and lipid droplets-specific imaging properties. These results implied that DSE-active p-RBZ had the potential to be developed as a mechanical-force sensor and lipid droplets imaging probe.

CO2 laser-induced long-period fiber grating in the dispersion turning point

A CO2 laser-induced long-period fiber grating (LPFG) in the dispersion turning point (DTP) has been proposed in this work, which has demonstrated the possibility of fabricating LPFG with a shorter period of 115 μm in a thin single-mode fiber (SMF) without etching cladding. The LPFG working near DTP was also induced in a conventional SMF by CO2 laser after etching cladding, whose grating period was 196 μm. Then, the refractive index (RI) sensitivity of LPFG based on thin SMF was optimized by fully combining DTP and cladding reduction. Considering the sensor probe's mechanical strength comprehensively, the thin SMF cladding was etched to 51.03 μm to ensure cladding mode LP1,6 work near DTP, which can result in an average RI sensitivity of 2117.12 nm/RIU in the RI range of 1.33222 to 1.39018. Based on its excellent RI sensing performance, the proposed LPFG is a prospective sensor that can be applied to significant fields such as environmental, chemical, or biological parameters measurement. At the same time, this study provides a low-cost path to fabricate LPFG worked in DTP for most researchers.

Wide Temperature Range and Low Temperature Drift Eddy Current Displacement Sensor Using Digital Correlation Demodulation

Conventional eddy-current sensors have the advantages of being contactless and having high bandwidth and high sensitivity. They are widely used in micro-displacement measurement, micro-angle measurement, and rotational speed measurement. However, they are based on the principle of impedance measurement, so the influence of temperature drift on sensor accuracy is difficult to overcome. A differential digital demodulation eddy current sensor system was designed to reduce the influence of temperature drift on the output accuracy of the eddy current sensor. The differential sensor probe was used to eliminate common-mode interference caused by temperature, and the differential analog carrier signal was digitized by a high-speed ADC. In the FPGA, the amplitude information is resolved using the double correlation demodulation method. The main sources of system errors were determined, and a test device was designed using a laser autocollimator. Tests were conducted to measure various aspects of sensor performance. Testing showed the following metrics for the differential digital demodulation eddy current sensor: nonlinearity 0.68% in the range of ±2.5 mm, resolution 760 nm, maximum bandwidth 25 kHz, and significant suppression in the temperature drift compared to analog demodulation methods. The tests show that the sensor has high precision, low temperature drift and great flexibility, and it can instead of conventional sensors in applications with large temperature variability.

Electrochemically nanotuned surface comprising 3D bimetallic dendrites fabricated on MWCNT for detection of 1,4-dioxane in water

Water quality has become one of the most serious environmental problems throughout the globe. The recalcitrant molecule, 1,4-Dioxane (1,4-D) has been recognized as a pollutant of rising concern in water, according to the World Health Organization (WHO), and can cause harm to aquatic organisms, animals, and even humans. Thus, it is important to detect 1,4-D in water bodies accurately and sensitively. In light of this, by fine-tuning the electrodeposition conditions, a novel bimetallic copper and gold nanodendritic structure was fabricated on the multiwalled carbon nanotube (MWCNT) functionalized glassy carbon electrode (GCE). The nanosensor was characterized by several physical and electrochemical techniques. The sensor probe exhibits good analytical performance and possess linear dynamic ranges (LDR) between 5 to 103 nM and 0.5 × 105 to 2 × 105 nM. The sensor showed limit of detection (LOD) and limit of quantification (LOQ) of 3.27 ± 0.04 pM and 10.92 ± 0.07 pM, respectively, with a mean response time of 1.65 ± 0.05 s. The sensor's performance was analyzed using tap water and Ganga water, with 90.24–99.57 % and 90.05–98.88 % of 1,4-D recovered without interference, respectively. The entire process of fabricating the surface and testing the 1,4-D takes hardly around 30 min, showing the sensor's applicability in monitoring 1,4-D in the environment.

A novel method for 3D reconstruction in tight and restricted space based on improved line-structured light

Three-dimensional (3D) reconstruction techniques have been widely employed in many fields. But precise endoscopic 3D measurement inside of objects, especially in tight and restricted spaces, is still a challenge since there is no easy access for measurement tools. Endoscope with 2D-view function has been widely used. However, the precise measurement technology of the inner surface of small hollow objects has not been widely researched. The components of the existing endoscope three-dimensional measuring probe are complex, expensive and not performed well in accuracy. Thus, a novel method and a miniaturized endoscopic 3D sensor is introduced. To be suit in tight and restricted space, the sensor probe prototype has a maximum 6 mm in thickness. The miniatured sensor prototype is mainly based on improved line-structured light, which performs better in robustness and measurement accuracy than coded projection. Especially, the components are inexpensive and easily available, which reduces the manufacturing cost thus making it easily to popularize in industry. Correspondingly, to ensure the sensor measurement accuracy, we also proposed a calibration method for a miniature line-structured light system based on specially designed planar targets. It should be noted that the 3D extension of the line-structured light system relies on the movement of the translation stage. Taking full account of the characteristics of the sensor prototype, a high-precision direction calibration method of the translation stage based on joint multi-calibration position noise estimation is proposed. Finally, the accuracy experiment is carried out on the gauge block to verify that the measurement method proposed can achieve high-precision 3D reconstruction in a restricted space, and that the 3D reconstruction error is less than 10µm.

A coumarin derivative-based turn-on fluorescent probe for real-time applications of hydrazine detection in environment and bioimaging

Increasing the concentration of hydrazine is a major toxic threat to living beings and the environment. Thus, a potential probe was designed, including coumarin-integrated N-(diethylamino)salicylaldehyde (Cou) and 2,4-dinitrobenzoate (DNP), to develop the Cou-DNP probe sensor. The probe can react with hydrazine through the nucleophilic substitution reaction with the elimination of an ester (O–CO-) group besides achieving a “turn-on” fluorescence. This enhanced emission is because of the intramolecular charge transfer (ICT) sensing mechanism that exists between Cou and DNP. Also, the cleavage of an ester bond and the result of coumarin phenol (Cou) were verified through characterizations of 1H NMR, HR-MS, and density-functional theory (DFT) calculations. The application of Cou-DNP was effectively demonstrated by tracking gaseous hydrazine with paper strips; also, soil and actual samples (food, water) were examined to detect hydrazine in the solution phase. Moreover, a time-dependent study was conducted in HeLa cells to monitor the exo- and endogenous (in situ) hydrazine levels using hydrazine solution and isoniazid as a metabolite of hydrazine release, respectively. The probe-pretreated onion epidermal cells were imaged with hydrazine in the time interval of 0–5 min. We anticipate that a probe with the aid of a new recognition unit will provide a replacement for the traditional methods in detecting the toxic analyte hydrazine in real and bio-samples.

AB-452654-1 ESOPHAGEAL PROTECTION STRATEGIES FOR ABLATION OF ATRIAL FIBRILLATION: COMPARATIVE RESULTS BASED ON CONSECUTIVE ENDOSCOPIC EVALUATION

Catheter ablation is an effective treatment for restoring sinus rhythm in AF and has become a worldwide procedure. Although rare, atrioesophageal fistula (AEF) is among the most common lethal complications of this procedure. Several strategies have been employed to prevent esophageal lesions, including single and multi-sensor esophageal probes, different energy strategies, esophageal displacement and regular esophageal monitoring using esophagogastroduodenoscopy (EGD) to identify asymptomatic esophageal lesions that could evolve to AEF. As the occurrence of AEF is rare, one of the approaches to evaluate which strategy is more effective in preventing esophageal lesions is studying the incidence of asymptomatic on routine endoscopy. The objective of this study is to present the five-year experience of a systematic endoscopic surveillance of esophageal injury after AF catheter ablation and analyse if there is an appropriate strategy related to a lower incidence of lesions. This is a retrospective single center registry of all AF ablation procedures performed from 2016 to 2021, in which an endoscopy was performed after ablation in all cases. A total of 660 AF ablation procedures in 626 different patients were performed in that period. A control EGD data could be recorded in 609 ablation procedures (92,3%). Most of the patients were male with paroxysmal AF. Esophageal temperature monitoring with single Sensor Probe was performed in 48.4% and with multi–sensor probe in 24.4% of the cases. Most of the patients presented no esophageal lesions (71.8%). Mild lesion was found on 90 patients (14.8%) and severe lesion was found on 56 (9.2%) of them. The use of multisensor esophageal probe (P<0.001), male gender (P=0.007) and the use of PVAC (P=0.018) were correlated with less frequent thermal lesions on multivariate analysis. Most of the lesions were healed on control endoscopy. The incidence of esophageal lesions on routine EGD after AF catheter ablation is high, but most of the cases the lesion is spontaneously healed. The use of multisensor probe, PVAC and male gender were correlated to fewer thermal lesions.

Estimation of the Electron Density in the Near 3–4 RE Magnetosphere Based on the Measurement of the Interball-2 Satellite Potential

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.