Probe Device Research Articles

Advanced Neural Probe Sensors toward Multi‐Modal Sensing and Modulation: Design, Integration, and Applications

AbstractNeural probe devices have undergone significant advancements in recent years, evolving from basic single‐functional devices to sophisticated integrated systems capable of sensing, stimulating, and regulating neural activity. The neural probes have been demonstrated as effective tools for diagnosing and treating numerous neurological disorders, as well as for understanding sophisticated connections and functions of neuron circuits. The multifunctional neural probe platforms, which combine electrical, optical, and chemical sensing capabilities, hold promising potential for revolutionizing personalized healthcare through closed‐loop neuromodulation, particularly in the treatment of conditions such as epilepsy, Parkinson's disease, and depression. Despite these advances, several challenges remain to be further investigated, including biocompatibility, long‐term signal quality and stability, and miniaturization, all of which hinder their broader clinical application. This paper provides an overview of the design principles of the neural probe structures and sensors, fabrication strategies, and integration techniques for the advanced multi‐functional neural probes. Key electrical, optical, and chemical sensing mechanisms are discussed, along with the selection of corresponding functional materials. Additionally, several representative applications are highlighted, followed by a discussion of the challenges and opportunities that lie ahead for this emerging field.

Automated membrane characterization: In-situ monitoring of the permeate and retentate solutions using a 3D printed permeate probe device

Self-driving laboratories and automated experiments can accelerate the design workflow and decrease errors associated with experiments that characterize membrane transport properties. Within this study, we use 3D printing to design a custom stirred cell that incorporates inline conductivity probes in the retentate and permeate streams. The probes provide a complete trajectory of the salt concentrations as they evolve over the course of an experiment. Here, automated diafiltration experiments are used to characterize the performance of commercial NF90 and NF270 polyamide membranes over a predetermined range of KCl concentrations from 1 to 100 mM. The measurements obtained by the inline conductivity probes are validated using offline post-experiment analyses. Compared to traditional filtration experiments, the probes decrease the amount of time required for an experimentalist to characterize membrane materials by more than 50× and increase the amount of information generated by 100×. Device design principles to address the physical constraints associated with making conductivity measurements in confined volumes are proposed. Overall, the device developed within this study provides a foundation to establish high-throughput, automated membrane characterization techniques.

Activatable near-infrared fluorescent/photoacoustic probe for rapid identification of β-lactam-resistant bacteria

Early identification of antimicrobial-resistant (AMR) bacteria is of great significance to guide the use of drugs and reduce the risk of AMR infection. One of the main reasons for AMR resistance to antibiotic therapy is the production of β-lactamase that decomposes antibiotics. Accurate and rapid detection of β-lactamase is crucial o deal with bacterial resistance. Herein, a dual-modal probe with near-infrared fluorescence (NIRF) and photoacoustics (PA) to rapid detection of β-lactamases (TEM-1) and β-lactam-resistant bacteria (BLRB) was ingeniously designed and developed. The NIRF and PA signal of CyPA-L can be fully turned on after 7 min of incubation of CyPA-L with TEM-1, and also showed high selectivity for TEM-1 among multiple interfering analytes. Notably, a portable PA device with immediate detection (POCT) capability was developed to detect β-lactamase and BLRB through PA signaling of CyPA-L. The design of probe and facile device will provide a new way for the diagnosis and symptomatic treatment of early drug-resistant bacteria.

Photon-assisted electron depopulation of 4H-SiC/SiO2 interface states in n-channel 4H-SiC metal–oxide–semiconductor field effect transistors

4H-SiC/SiO2 interface states play a major role in the performance and reliability of modern 4H-SiC metal–oxide–semiconductor field effect transistors (MOSFETs). To gain new insights into these interface states, we developed a cryogenic measurement technique that uses photon-assisted electron depopulation to probe device performance limiting 4H-SiC/SiO2 interface states. This technique enables the characterization of shallow as well as deep states at the 4H-SiC/SiO2 interface of fully processed devices using a cryogenic probe station. Our method is performed on n-channel 4H-SiC MOSFET test structures with deposited oxide and postoxidation anneal. We identify conditions under which the electrons remain trapped at 4H-SiC/SiO2 interface states and trigger the controlled photon-assisted electron depopulation within a range of photon energies. This allows us to prove the presence of near interface traps, which have previously been found in thermally grown 4H-SiC MOS structures. Our results are supported by device simulations. Additionally, we study the impact of irradiation intensity and light exposure time on the photon-induced processes.

Bilaterally Aligned Electroosmotic Flow Generated by Porous Microneedle Device for Dual-Mode Delivery.

Here, a novel porous microneedle (PMN) device with bilaterally aligned electroosmotic flow (EOF) enabling controllable dual-mode delivery of molecules is developed. The PMNs placed at anode and cathode compartments are modified with anionic poly-2-acrylamido-2-methyl-1-propanesulfonic acid and cationic poly-(3-acrylamidopropyl) trimethylammonium, respectively. The direction of EOF generated by PMN at the cathode compartment is, therefore, reversed from cathode to anode, countering the unwanted cathodal suctioning of interstitial fluid caused by reverse iontophoresis. With the bilateral alignment of EOF, the versatility of the proposed device is evaluated by delivering molecules with different charges and sizes using Franz cell. In addition, a 3D printed probe device is developed to ease practical handling and minimize electrical stimulation by integrating two PMNs in closed proximity. Finally, the performance of the integrated probe device is demonstrated by dual delivery of a variety of molecules (methylene blue, rhodamine B, and fluorescein isothiocyanate-dextran) using pig skin and vaccination using mice with delivered ovalbumin.

New suture probe canaloplasty combined with suprachoroidal collagen implantation.

To present the modified surgery technique of new suture probe canaloplasty with a specially prepared monofilament 4.0 polypropylene suture combined with suprachoroidal drainage (ScD) and collagen sheet implantation for non-penetrating glaucoma surgery. Prospective study with a twelve months follow-up. A standard 4/0 polypropylene suture (ProleneTM by Ethicon; thickness: approximately 250m) is cut and shaped with an ophthalmic knife (MANI® Crescent Knife, Mani Inc 8-3 Kiyohara Industrial Park, Utsunomiya, Tochigi 321-3231, Japan) to create a blunt end without sharp or compressed edges. This improves suture probe canaloplasty by providing a more stable and smoother probing device. Schlemm's canal is prepared using the standard technique of canaloplasty with suprachoroidal drainage. Then, instead of using the canaloplasty microcatheter or the previously published 6/0 double-helix suture, Schlemm's canal is probed with the blunt ending of the 4/0 Prolene suture. After successful 360-degree probing, a doubled 10/0 polypropylene tension suture is threaded through the tip of the 4/0 suture. The 4/0 suture is then pulled back and the 10/0 tension sutures are tied at both ends to tension Schlemm's canal. A special collagen sheet (Ologen®) is placed in suprachoroidal space, and the scleral flap is firmly sewed. 115 eyes were included in this prospective study. In 113 cases the Schlemm's canal could completely be probed with the suture probe and canaloplasty with ScD and collagen sheet implantation succeeded. In two cases the intervention was transformed to 360-degree suture trabeculotomy due to an intraoperative cheese-wiring. Twelve months after successful new suture probe canaloplasty with ScD and Collagen Implantation the IOP had decreased by 37.1% (from 21.6 ± 6.0mmHg with 3.3 different IOP lowering eye drops to 13.5 ± 3.5mmHg with 1.0 eye drops). 16 Patients did not achieve sufficient IOP levels and underwent 360-degree suture trabeculotomy during the follow-up. One patient had to be treated with further glaucoma surgery to achieve a sufficient IOP level. Complications were hyphema, postoperative IOP elevation and transient hypotony. No serious or sight-threatening complications occurred. New suture probe canaloplasty with ScD and collagen sheet implantation yields the opportunity to conduct a cost-effective canaloplasty easier and less complicated than with the previously described method with the twisted 6/0 suture. The safety profile and IOP lowering effect is comparable. In cases where complete probing fails, there is still the opportunity to switch to suture trabeculotomy over the majorly probed part of Schlemm's canal. The pressure lowering effect of the deep sclerectomy with ScD and suprachoroidal collagen sheet implant seems to have an additional impact on the sufficient pressure lowering procedure.

Lanthanide metal-organic framework-based surface molecularly imprinted polymers ratiometric fluorescence probe for visual detection of perfluorooctanoic acid with a smartphone-assisted portable device

Perfluorooctanoic acid (PFOA) poses a threat to the environment and human health due to its persistence, bioaccumulation, and reproductive toxicity. Herein, a lanthanide metal-organic framework (Ln-MOF)-based surface molecularly imprinted polymers (SMIPs) ratiometric fluorescence probe (Eu/Tb-MOF@MIPs) and a smartphone-assisted portable device were developed for the detection of PFOA with high selectivity in real water samples. The integration of Eu/Tb MOFs as carriers not only had highly stable multiple emission signals but also prevented deformation of the imprinting cavity of MIPs. Meanwhile, the MIPs layer preserved the fluorescence of Ln-MOF and provided selective cavities for improved specificity. Molecular dynamics (MD) was employed to simulate the polymerization process of MIPs, revealing that the formation of multiple recognition sites was attributed to the establishment of hydrogen bonds between functional monomers and templates. The probe showed a good linear relationship with PFOA concentration in the range of 0.02–2.8 μM, by giving the limit of detection (LOD) of 0.98 nM. Additionally, The red-green-blue (RGB) values analysis based on the smartphone-assisted portable device demonstrated a linear relationship of 0.1–2.8 μM PFOA with the LOD of 3.26 nM. The developed probe and portable device sensing platform exhibit substantial potential for on-site detecting PFOA in practical applications and provide a reliable strategy for the intelligent identification of important targets in water environmental samples.

Rational Integration of Nanozyme Probe and Smartphone Device for On‐Site Analysis

AbstractOn‐site detection featuring miniaturized, integrated analytical device and rapid data feedback has encouraged a great deal of attention, especially in the current context of pandemic diseases occurring with high frequency worldwide. This convenient detection device constitutes a stable recognition element and a portable signal treatment and readout module. In this regard, the enzyme‐mimic nanomaterials (nanozymes) with the merits of structural stability, cost efficiency, scale‐up synthesis and high recyclability well meet the requirements for recognition unit set‐up. While the all‐pervading smartphone, which enables the data collection through photography or wireless transmission, holds numerous opportunities in the design of hand‐held analytical device. In this review, we summarize the advances of nanozyme‐smartphone integrated platforms, with special emphasis of the signal transduction principles involving colorimetric, chemiluminescence, and electrochemical signals. The diversified on‐site applications in terms of biological, environment and food analysis are showcased. Finally, the current challenges as well as the future perspectives on nanozyme design, sensing diversity and smartphone analysis are discussed.

Adverse events associated with the gold probe and the injection gold probe devices used for endoscopic hemostasis: A MAUDE database analysis.

Gastrointestinal (GI) bleeding accounts for over half a million admissions annually and is the most common GI diagnosis requiring hospitalization in the United States. Bipolar electrocoagulation devices are used for the management of gastrointestinal bleeding. There is no data on device-related adverse events for gold probe (GP) and injection gold probe (IGP). To analyze this using the Food and Drug Administration (FDA's) Manufacturer and User Facility Device Experience (MAUDE) database from 2013 to 2023. We examined post-marketing surveillance data on GP and IGP from the FDA MAUDE database to report devicerelated and patient-related adverse events between 2013-2023. The MAUDE database is a publicly available resource providing over 4 million records relating to medical device safety. Statistical analyses were performed using IBM SPSS Statistics V.27.0 (IBM Corp., Armonk, NY, United States). Our search elicited 140 reports for GP and 202 reports for IGP, respectively, during the study period from January 2013 to August 2023. Malfunctions reportedly occurred in 130 cases for GP, and actual patient injury or event occurred in 10 patients. A total of 149 patients (74%) reported with Injection GP events suffered no significant consequences due to the device failure, but 53 patients (26%) were affected by an event. GP and IGP are critical in managing gastrointestinal bleeding. This study of the FDA MAUDE database revealed the type, number, and trends of reported device-related adverse events. The endoscopist and support staff must be aware of these device-related events and be equipped to manage them if they occur.

Color Routing of the Emission from Magnetic and Electric Dipole Transitions of Eu3+ by Broken-Symmetry TiO2 Metasurfaces.

Manipulation of magnetic dipole emission with resonant photonic nanostructures is of great interest for both fundamental research and applications. However, obtaining selective control over the emission properties of magnetic dipole transitions is challenging, as they usually occur within a manifold of spectrally close emission lines associated with different spin states of the involved electronic levels. Here we demonstrate spectrally selective directional tailoring of magnetic dipole emission using designed photonic nanostructures featuring a high quality factor. Specifically, we employ a hybrid nanoscale optical system consisting of a Eu3+ compound coupled to a designed broken-symmetry TiO2 metasurface to demonstrate directional color routing of the compound's emission through its distinct electric and magnetic-dominated electronic transition channels. Using low numerical aperture collection optics, we achieve a fluorescence signal enhancement of up to 33.13 for the magnetic-dominated dipole transition at 590 nm when it spectrally overlaps with a spectrally narrow resonance of the metasurface. This makes the, usually weak, magnetic dipole transition the most intense spectral line in our recorded fluorescence spectra. By studying the directional emission properties for the coupled system using Fourier imaging and time-resolved fluorescence measurements, we demonstrate that the high-quality-factor modes in the metasurface enable free-space light routing, where forward-directed emission is established for the magnetic-dominated dipole transition, whereas the light emitted via the electric dipole transition is mainly directed sideways. Our results underpin the importance of magnetic light-matter interactions as an additional degree of freedom in photonic and optoelectronic systems. Moreover, they facilitate the development of spectrometer-free and highly integrated nanophotonic imaging, sensing, and probing devices.

Spin-polarized Majorana zero modes in proximitized superconducting penta-silicene nanoribbons

We theoretically propose penta-silicene nanoribbons (p-SiNRs) with induced p-wave superconductivity as a platform for the emergence of spin-polarized Majorana zero-modes (MZMs). The model explicitly considers the key ingredients of well-known Majorana hybrid nanowire setups: Rashba spin-orbit coupling, magnetic field perpendicular to the nanoribbon plane, and first nearest neighbor hopping with p-wave superconducting pairing. The energy spectrum of the system, as a function of chemical potential, reveals the existence of MZMs with a well-defined spin orientation localized at the opposite ends of both the top and bottom chains of the p-SiNR, associated with well-localized and nonoverlapping wave function profiles. Well-established experimental techniques enable the fabrication of highly ordered p-SiNRs, complemented by a thin lead film on top, responsible for inducing p-wave superconductivity through proximity effect. Moreover, the emergence of MZMs with explicit opposite spin orientations for some set of model parameters opens a new avenue for exploring quantum computing operations, which accounts for both MZMs and spin properties, as well as for new MZMs probe devices based on spin-polarized electronic transport mechanisms.

ELECTRICAL PROPERTIES OF ZnO(x)–Co3O4(1−x) (x = 0.7, 0.5, 0.3) OXIDE THIN FILMS VIA FOUR POINT PROBE DEVICE: SUBSTRATE TEMPERATURE EFFECT ON THE ELECTRICAL PROPERTIES

ZnO[Formula: see text]–Co3O[Formula: see text]([Formula: see text]= 0.7, 0.5, 0.3) oxide thin films were synthesized via spray pyrolysis deposition. The obtained films were investigated to find the surface electrical resistance ([Formula: see text]) and conductance ([Formula: see text]) using the four point probe device and the Van der Pauw mathematical relation to estimate the electrical resistivity ([Formula: see text]) and conductivity ([Formula: see text]). In addition, the electrical resistance, conductance, resistivity and conductivity were obtained. From the obtained results, we have observed that the electrical quantities of the nanocomposite films are close to the interval bounds of the electrical quantities of the pure materials. For example, at room temperature, the electrical resistivity values of ZnO, Co3O4, ZnO[Formula: see text]–Co3O[Formula: see text], ZnO[Formula: see text]–Co3O[Formula: see text] and ZnO[Formula: see text]–Co3O[Formula: see text] were found to be around 6.89 × 10[Formula: see text], 1.58−103, 339.75, 611.55 and 1333.632 Ω.cm, respectively. This note can be depending on the density (concentration) of the carriers (electron/holes) of the constituents (pure material) of the composite material. Besides, the variations of these quantities were measured as a function of the substrate temperature. It was found that the conductance and conductivity vary proportionally with the temperature, but the electrical resistance and resistivity were inversely proportional. This remark indicates a semiconducting electrical behavior. The possible reaction mixture of pure semiconductors materials in the synthesis process is explained. The studied semiconductor oxides show interesting electrical properties, which makes them potential candidates to be used in various optoelectronic devices.

Transport properties of GaAs Co-doped H-passivated low-buckled and high-buckled zigzag silicene nanoribbon two probe devices

Transport properties of GaAs Co-doped H-passivated low-buckled and high-buckled zigzag silicene nanoribbon two probe devices

Development and Evaluation of a Flexible PVDF-Based Balloon Sensor for Detecting Mechanical Forces at Key Esophageal Nodes in Esophageal Motility Disorders.

Prevailing methods for esophageal motility assessments, such as perfusion manometry and probe-based function imaging, frequently overlook the intricate stress fields acting on the liquid-filled balloons at the forefront of the probing device within the esophageal lumen. To bridge this knowledge gap, we innovatively devised an infusible flexible balloon catheter, equipped with a quartet of PVDF piezoelectric sensors. This design, working in concert with a bespoke local key-node analytical algorithm and a sensor array state analysis model, seeks to shed new light on the dynamic mechanical characteristics at pivotal esophageal locales. To further this endeavor, we pioneered a singular closed balloon system and a complementary signal acquisition and processing system that employs a homogeneously distributed PVDF piezoelectric sensor array for the real-time monitoring of dynamic mechanical nuances in the esophageal segment. An advanced analytical model was established to scrutinize the coupled physical fields under varying degrees of balloon inflation, thereby facilitating a thorough dynamic stress examination of local esophageal nodes. Our rigorous execution of static, dynamic, and simulated swallowing experiments robustly substantiated the viability of our design, the logical coherence of our esophageal key-point stress analytical algorithm, and the potential clinical utility of a flexible esophageal key-node stress detection balloon probe outfitted with a PVDF array. This study offers a fresh lens through which esophageal motility testing can be viewed and improved upon.

Analysis of Reported Adverse Events Associated With the Use of Functional Lumen Imaging Probe Devices in the Esophagus and Stomach: An FDA MAUDE Database Study

The endoscopic Functional Lumen Imaging Probe (FLIP) devices are used to evaluate pressure changes, diameter, and volume of the esophagus. We used the FDA’s MAUDE database to collect post-marketing surveillance data on these devices from January 2009 to September 2022. Forty-Five device-related events and thirty-six patient-related adverse events were analyzed. The most common device issue for the diagnostic FLIP device was therapeutic/diagnostic failure (n = 6), while the most frequent issue with the therapeutic FLIP device was adverse events without an identified device or use problem (n = 11). Patient-related adverse events were extremely rare with the diagnostic FLIP and the most common patient-related adverse event with the therapeutic FLIP was perforation (n = 11). Endoscopists need to be mindful of these potential technical issues and adverse events while using these devices.

Thoracoscopic Anterior Vertebral Body Tethering in Lenke Type-1 Right Adolescent Idiopathic Scoliosis.

Vertebral body tethering (VBT) is indicated for skeletally immature patients with progressive adolescent idiopathic scoliosis (AIS) who have failed or are intolerant of bracing and who have a major coronal curve of 40° to 65°. The vertebral body must be structurally and dimensionally adequate to accommodate screw fixation, as determined radiographically. The best indication for VBT is a flexible single major thoracic curve with nonstructural compensating lumbar and proximal thoracic curves (Lenke 1A or 1B). VBT allows for progressive correction of the deformity without spinal fusion by utilizing a minimally invasive fluoroscopic technique. The procedure for a right thoracic curve is performed with use of a right thoracoscopic approach with the patient in the left lateral decubitus position. The thoracoscope is introduced through a portal at the apex of the curvature in the posterior axillary line. Instrument portals are created lateral to each vertebral body in the mid-axillary line. Screws are inserted into each vertebral body under biplanar fluoroscopic control and with intraoperative neuromonitoring. An electroconductivity probing device, while not mandatory, is routinely utilized at our practice. The tether is attached to the most proximal screw of the construct, and then reduction is obtained sequentially by tensioning the tether from one vertebral screw to the next. Bracing is the gold-standard treatment for progressive AIS involving the immature spine. The most commonly utilized surgical treatment is posterior spinal fusion (PSF), which should be considered when the major coronal curve exceeds 45°. PSF has proven to be a dependable technique to correct scoliotic deformities. It has a low complication rate and good long-term outcomes. However, concerns exist regarding the stiffness conferred by PSF and the long-term effects of adjacent segment disease. Thus, interest had developed in non-fusion solutions for AIS correction. VBT utilizes the Hueter-Volkmann principle to guide growth and correct deformity. Compressive forces applied to the convexity of the deformity by a polyethylene tether allow the patient's growth to realign the spine. Intraoperative correction triggers growth modulation, and most of the modulation seems to occur during the first 12 months postoperatively. The best results have been seen with a short Lenke type-1A curve in a patient with closed triradiate cartilage, a Risser 3 or lower (ideally Risser 0) iliac apophysis, and a flexible curve characterized by a 50% reduction of the major coronal curve angle on side-bending radiographs. In 57 immature patients with a Lenke type-1A or 1B curve (i.e., a 30° to 65° preoperative Cobb angle), Samdani et al.3 found a main thoracic Cobb angle reduction from 40° ± 7° preoperatively to 19° ± 13° at 2 years after VBT. In the sagittal plane, the T5-T12 kyphosis measured 15° ± 10° preoperatively, 17° ± 10° postoperatively, and 20° ± 13° at 2 years. No major neurologic or pulmonary complications occurred. A total of 7 (12.3%) of the 57 patients underwent surgical revision, including 5 for overcorrection and 2 to span additional vertebrae. In a study of 21 skeletally mature patients, Pehlivanoglu et al.4 found that the Cobb angle was reduced from 48° preoperatively to 16° on the first-erect postoperative radiograph and finally to 10° at the latest follow-up (mean, 27.4 months). The 2 main complications of VBT reported in the literature are overcorrection and tether breakage. Both may require revision, which explains the higher rate of revision observed for VBT compared with PSF. Good patient selection is important. VBT is most appropriate in cases of a flexible Lenke type-1A or 1B curve in an immature child before Risser stage 3 and after triradiate cartilage closure.Always monitor and control screw positioning in both anteroposterior and lateral planes fluoroscopically.The screws should be placed parallel to the vertebral end plates or, even better, be angled inferiorly for the upper vertebrae and angled superiorly for the lower vertebrae to decrease the risk of pull-out when tensioning the device and during growth modulation. Less tension on the uppermost and lowermost instrumented vertebrae than at the apex, as controlled by the tensioning device, can also help to limit pull-out. VBT = vertebral body tetheringAIS = adolescent idiopathic scoliosisIONM = intraoperative neuromonitoringPSF = posterior spinal fusionUIV = upper instrumented vertebraLIV = lower instrumented vertebraAP = anteroposteriorK-wire = Kirschner wire.

Triarylamine-based polyamide containing adamantane group as Fe3+ probe and electrochromic smart devices

A new triarylamine-based polyamide was synthesized from 1,4-cyclohexanedicarboxylic acid and diamine monomer containing adamantane group (PA-CA), which exhibits high fluorescence quantum up to 46.1% and excellent electrochromic behaviors. The photoluminescence of PA-CA was quenched by coordination and internal filtration effect to realize Fe3+ response. Neutral colorless PA-CA film was converted to the oxidized blue in the electrochemical oxidation process and the maximum transmittance reached 80%, and the transmittance still exceeded 55% after 10,000 s. A Sandwich structure electrochromic device with PA-CA as the active layer was constructed with a simple strategy and different contents were displayed through patterned customization. Electrofluorochromic performance was regulated and decoding information was customized by applying voltage changes of the light and dark for PA-CA film. The applications of multifunctional integrated PA-CA responding to stimulus have broad prospects in the field of Fe3+ fluorescence sensors, photodetectors and multicolor electrochromic display devices.

Corrosion Current Density of API 5L X65 Carbon Steel in Contact with Natural Callovian-Oxfordian Clay Pore Water, Assessed by Various Electrochemical Methods over 180 Days

Near-neutral pH and a low redox potential are considered favorable conditions for immobilizing radionuclides in deep repository systems within clay formations. Cigeo is the future French Industrial Center for Geological Disposal for high- and intermediate-level long-lived radioactive waste, to be built at a depth of 500 m within the Callovian–Oxfordian clay. In-depth knowledge of the mechanisms and kinetics of corrosion occurring on the surface of API 5L X65 (X65) carbon steel tubing is essential for the reversible nuclear waste management of the Cigeo site. By using all-solid and robust handmade electrodes in addition to electrochemical and gravimetric techniques, we determined the corrosion phenomenology and kinetics of X65 in contact with natural Cox pore water in equilibrium with its rock gases, flowing continuously through a multi-parameter probe device and placed at a depth of 500 m at the Bure Underground Research Laboratory, for over 180 days. Two iron oxidants were encountered, namely, depleted dioxygen (O2) and proton H(I), accompanied by hydrogen sulfide. Corrosion mechanisms and kinetics were well established for the two X65 electrodes, whether electrochemically perturbed or not. The corrosion thickness loss rates, determined by both electrochemical and gravimetric techniques, were between 0.016 and 0.032 mm/year. This study demonstrates, on site, the reliability of a developed methodology for continuous monitoring of the corrosion kinetics of the API 5L X65 carbon steel at the same time as the temporal variation of the key geochemical parameters of the fluid was assessed.

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.

Pyloric Functional Lumen Imaging Probe Measurements Are Dependent on Balloon Position.

The functional lumen imaging probe (FLIP) device has been used to assess pyloric dysfunction in patients with gastroparesis. We aim to investigate whether varying FLIP catheter positions affect pyloric FLIP measurements. Patients undergoing endoscopy for chronic unexplained nausea and vomiting (CUNV) or gastroparesis were prospectively enrolled. FLIP balloon was adjusted for 3 positions within the pylorus: (1) proximal position, 75% of FLIP balloon in the duodenum and 25% in the antrum; (2) middle position, 50% in the duodenum and 50% in the antrum; and (3) distal position, 25% in the duodenum and 75% in the antrum. Pylorus cross-sectional area (CSA), intra-bag pressure (P), and distensibility indices (DI) were measured for 30, 40, and 50-mL balloon volumes. Fluoroscopic images were obtained to confirm FLIP balloon geometry. Data was analyzed separately using FLIP Analytic and customized MATLAB software. Twenty-two patients with CUNV (n = 4) and gastroparesis (n = 18) were enrolled. Pressures were significantly higher in the proximal position compared to the middle and distal positions. CSA measurements were significantly higher at the proximal and middle positions for 30-mL and 40-mL volume compared to the distal position values. DI values were significantly lower at the proximal positions for 40-mL and 50-mL distensions when compared to the middle and distal positions. Fluoroscopic images confirmed increased balloon bending when placed mostly in the duodenum. FLIP balloon position within the pylorus directly affects balloon geometry which significantly affects P, CSA, and DI measurements. Standardized pyloric FLIP protocols and balloon design adjustments are needed for the continued application of this technology to the pylorus.