Resistance Measurements Research Articles

Differential Hall Effect Metrology for Electrical Characterization of Advanced Semiconductor Layers

Semiconductor layers employed in fabricating advanced node devices are becoming thinner and their electrical properties are diverging from those established for highly crystalline standards. Since these properties also change as a function of depth within the film, accurate carrier profiling solutions are required. The Differential Hall Effect (DHE) technique has the unique capability of measuring mobility and carrier concentration (active carriers) through the depth of a semiconductor film. It comprises making successive sheet resistance and sheet Hall coefficient measurements as the thickness of the electrically active layer at a test region is reduced through successive material removal steps. Difference equations are then used to process the data and plot the desired depth profiles. The fundamentals of DHE were established in 1960s. Recently, the adaption of electrochemical processing for the material removal steps, and the integration of all other functionalities in a Differential Hall Effect Metrology (DHEM) tool, has made this technique more practical and accurate and improved its depth resolution to a sub-nm range. In this contribution, we review the development history of this important technique and present data from recent characterization work carried out on Si, Ge and SiGe layers.

Simplification of continuous intracoronary thermodilution.

Continuous intracoronary thermodilution with saline allows for the accurate measurement of volumetric blood flow (Q) and absolute microvascular resistance (Rμ). However, this requires repositioning of the temperature sensor by the operator to measure the entry temperature of the saline infusate, denoted as Ti. We evaluated whether Ti could be predicted based on known parameters without compromising the accuracy of calculated Q. This would significantly simplify the technique and render it completely operator independent. In a derivation cohort of 371 patients with Q measured both at rest and during hyperaemia, multivariate linear regression was used to derive an equation for the prediction of Ti. Agreement between standard Q (calculated with measured Ti) and simplified Q (calculated with predicted Ti) was assessed in a validation cohort of 120 patients that underwent repeat Q measurements. The accuracy of simplified Q was assessed in a second validation cohort of 23 patients with [15O]H2O positron emission tomography (PET)-derived Q measurements. Simplified Q exhibited strong agreement with standard Q (r=0.94, confidence interval [CI]: 0.93-0.95; intraclass correlation coefficient [ICC] 0.94, CI: 0.92-0.95; both p<0.001). Simplified Q exhibited excellent agreement with PET-derived Q (r=0.86, CI: 0.75-0.92; ICC=0.84, CI: 0.72-0.91; both p<0.001). Compared with standard Q, there were no statistically significant differences between correlation coefficients (p=0.29) or standard deviations of absolute differences with PET-derived Q (p=0.85). Predicting Ti resulted in an excellent agreement with measured Ti for the assessment of coronary blood flow. It significantly simplifies continuous intracoronary thermodilution and renders absolute coronary flow measurements completely operator independent.

Regulatory effects of the p38 mitogen-activated protein kinase-myosin light chain kinase pathway on the intestinal epithelial mechanical barrier and the mechanism of modified Pulsatilla decoction in the treatment of ulcerative colitis.

To investigate the mechanism of the protective effect of modified Pulsatilla decoction (, MPD) on the mechanical barrier of the ulcerative colitis (UC) intestinal epithelium in vitro and in vivo. We established an intestinal epithelial crypt cell line-6 cell barrier injury model by using lipopolysaccharide (LPS). The model was then treated with p38 mitogen-activated protein kinase-myosin light chain kinase (p38MAPK-MLCK) pathway inhibitors, p38MAPK-MLCK pathway silencing genes (si-p38MAPK, si-NF-κB, and si-MLCK), and MPD respectively. Transepithelial electronic resistance (TEER) measurements and permeability assays were performed to assess barrier function. Immunofluorescence staining of tight junctions (TJ) was performed. In in vivo experiment, dextran sodium sulfate-induced colitis rat model was conducted to evaluate the effect of MPD and mesalazine on UC. The rats were scored using the disease activity index based on their clinical symptoms. Transmission electron microscopy and hematoxylin-eosin staining were used to examine morphological changes in UC rats. Western blotting and real-time quantitative polymerase chain reaction were performed to examine the gene and protein expression of significant differential molecules. In in vitro study, LPS-induced intestinal barrier dysfunction was inhibited by p38MAPK-MLCK pathway inhibitors and p38MAPK-MLCK pathway gene silencing. Silencing of p38MAPK-MLCK pathway genes decreased TJ expression. MPD treatment partly restored the LPS-induced decreased in TEER and increase in permeability. MPD increased the gene and protein expression of TJ, while down-regulated the LPS-induced high expression of p-p38MAPK and p-MLC. In UC model rats, MPD could ameliorate body weight loss and disease activity index, relieve colonic pathology, up-regulate TJ expression as well as decrease the expression of p-p38MAPK and p-MLC in UC rat colonic mucosal tissue. The p38MAPK-MLCK signaling pathway can affect mechanical barrier function and TJ expression in the intestinal epithelium. MPD restores TJ expression and attenuates intestinal epithelial barrier damage by suppressing the p38MAPK-MLCK pathway.

Structural, Mechanical and Thermal Behaviour of MWCNT-PCS Hybrid Polymer Matrix Nanocomposites: An Extension Study of Graphene-Epoxy Polymer Matrix Nanocomposites

This study extends previous research on graphene-epoxy nanocomposites by investigating the thermal, mechanical, electrical, and chemical properties of multi-walled carbon nanotube (MWCNT)-reinforced polycarbosilane (PCS) hybrid polymer matrix nanocomposites. Building on the foundational work that demonstrated the enhanced performance of graphene-epoxy nanocomposites, this research explores the potential of MWCNTs as a superior reinforcing agent within the PCS matrix. The MWCNT-PCS nanocomposites were synthesized and characterized using a comprehensive suite of techniques, including X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, specific gravity analysis and surface resistance measurements. The results indicate that MWCNT-PCS nanocomposites exhibit improved thermal stability, higher degradation temperatures, and enhanced thermal conductivity, along with significant improvements in mechanical strength and lower surface resistance, indicating superior electrical conductivity. Additionally, the chemical interactions between MWCNTs and the PCS matrix were analyzed to assess the dispersion and bonding quality, contributing to the overall performance of the nanocomposites. These findings suggest that MWCNT-PCS nanocomposites are promising candidates for high-performance applications in aerospace, where thermal stability, mechanical strength, electrical conductivity and chemical stability are critical. This paper not only confirms the benefits of MWCNT reinforcement but also provides a direct comparison with graphene-epoxy nanocomposites, underscoring the advancements made in this ongoing research.

Corrosion of Copper, Cupronickel, Nickel Aluminium Bronze and Super-Duplex Stainless Steel Rotating Cylinder Electrodes in Seawater under Turbulent Flow Conditions

The corrosion of uncoated metals in a marine environment restricts the choice of suitable engineering metals and alloys. Anodic dissolution of metal and cathodic reduction of oxygen are important processes and formation of a surface oxide film can affect both electrode reactions. Charge transfer and mass transfer data can provide information on corrosion rate and mechanism. Several metals and alloys having a history of use in marine engineering are considered, including copper, two copper alloys (cupronickel and nickel aluminium bronze) plus a more recent addition to strong, corrosion resistant alloys (a super duplex stainless steel). The rotating cylinder electrode offers the benefits of a controlled, turbulent flow of electrolyte, facilitating controlled mass transfer in a compact cell geometry which is well-suited to bench-top operation. These features are illustrated using a variety of electrochemical techniques, including open-circuit potential vs time monitoring, linear sweep voltammetry, rotation speed step- or potential step current transients and linear polarisation resistance measurements. Seawater taken from Langstone Harbour, Hampshire, UK, was filtered, air-saturated, pH 8.0 and maintained at 25 °C. Dimensionless group correlations and graphical plots (using an analogous approach to the Koutecky-Levich equation for an RDE) enabled contributions of charge transfer-, mixed- and mass transfer- controlled data to be appreciated, allowing the Tafel slopes of electrode reactions, the diffusion coefficient of dissolved oxygen, the mass transfer coefficient for oxygen reduction and the mean corrosion rate to be estimated.

Modeling The Hydrogen Crossover Through Membrane With And Without Catalyst Layers

The hydrogen crossover flux is expressed as a function of the difference in the partial pressure of hydrogen and total pressure difference between the supply and permeate sides of a membrane. The hydrogen crossover rate was measured under several operating conditions by micro gas chromatography. The permeation flux was not influenced by the total pressure difference up to 50 kPa. A bare Nafion membrane and the membrane with catalyst layers were modeled as a stack of bulk and skin layers. Hydrogen permeability of both samples showed identical bulk layer expressed by a power-law equation of the moisture content and an Arrhenius equation of temperature with an activation energy of 22.8 kJ mol–1. The measurement of skin layer resistance wasn’t successful since the skin layer resistance was too low to be measured. A skin layer of Nafion with a catalyst layer wasn’t observed due to formation of fused layer.

Modeling The Hydrogen Crossover Through Membrane With And Without Catalyst Layers

The hydrogen crossover flux is expressed as a function of the difference in the partial pressure of hydrogen and total pressure difference between the supply and permeate sides of a membrane. The hydrogen crossover rate was measured under several operating conditions by micro gas chromatography. The permeation flux was not influenced by the total pressure difference up to 50 kPa. A bare Nafion membrane and the membrane with catalyst layers were modeled as a stack of bulk and skin layers. Hydrogen permeability of both samples showed identical bulk layer expressed by a power-law equation of the moisture content and an Arrhenius equation of temperature with an activation energy of 22.8 kJ mol–1. The measurement of skin layer resistance wasn’t successful since the skin layer resistance was too low to be measured. A skin layer of Nafion with a catalyst layer wasn’t observed due to formation of fused layer.

Development of a multi-analysis model using an epithelial-fibroblast co-culture system as an alternative to animal testing.

The evaluation of respiratory chemical substances has been mostly performed in animal tests (OECD TG 403, TG 412, TG 413, etc.). However, there have been ongoing discussions about the limited use of these inhalation toxicity tests due to differences in the anatomical structure of the respiratory tract, difficulty in exposure, laborious processes, and ethical reasons. Alternative animal testing methods that mimic in vivo testing are required. Therefore, in this study, we established a co-culture system composed of differentiated epithelial cells under an air-liquid interface (ALI) system in the apical part and fibroblasts in the basal part. This system was designed to mimic the wound-healing mechanism in the respiratory system. In addition, we developed a multi-analysis system that simultaneously performs toxicological and functional evaluations. Several individual assays were used sequentially in a multi-analysis model for pulmonary toxicity. Briefly, cytokine analysis, histology, and cilia motility were measured in the apical part, and cell migration and gel contraction assay were performed by exposing MRC-5 cells to the basal culture. First, human airway epithelial cells from bronchial (hAECB) were cultured under air-liquid interface (ALI) system conditions and validated pseudostratified epithelium by detecting differentiation-related epithelial markers using Transepithelial Electrical Resistance (TEER) measurement, Hematoxylin and Eosin (H&E) staining, and immunocytochemistry (ICC) staining. Afterward, the co-culture cells exposed to Transforming growth factor-beta 1 (TGF-β1), a key mediator of pulmonary fibrosis, induced significant toxicological responses such as cytotoxicity, cell migration, and gel contraction, which are wound-healing markers. In addition, cilia motility in epithelial cells was significantly decreased compared to control. Therefore, the multi-analysis model with a 3D epithelial-fibroblast co-culture system is expected to be useful in predicting pulmonary toxicity as a simple and efficient high-throughput screening method and as an alternative to animal testing.

Characterization method of conductive film state of micro-cathode arc thrusters

Micro-Cathode Arc Thruster (μCAT) is an advanced electric propulsion system developed in the past decades to meet the maneuvering requirements of space microsatellites. However, the constraint on the its application is the short lifespan of the thruster. This is attributed to the conductive film, a key component of thruster discharge. In this study, we propose a measurement method for μCAT conductive film, and enables the evaluation of the evolution process of film thickness. The method is based on the four-probe resistivity testing theory and size effect fitting model, and establishes a method for characterizing the thickness and resistivity of μCAT conductive films. A comparison was made between the corrected resistivity test results of 1, 2, 5, and 10 μm film and the fitting results of the titanium film, revealing an error ofapproximately 10%. Additionally, a total of 2500 ignition experiments were conducted to verify the film thickness and resistance measurement of this method. This research serves as a valuable basis for the lifetime investigation of μCAT. Consequently, the thickness of the film progressively decreases with each discharge cycle, and the resistivity exhibits a corresponding increase due to the size effect. This method could be used as an effective method for exploring the μCAT lifespan and performance.

In-plane structural and electronic anisotropy of nanoporous Pt films formed by oblique angle deposition

Nanoporous Pt films fabricated by oblique angle deposition hold potential as electrocatalysts in various energy-related fields owing to their high surface area, structural stability, and adequate conductivity. In this study, we investigated the morphology, porosity, and electrical conductivity of nanoporous Pt thin films and systematically studied their interrelationships. Specifically, we revealed an in-plane anisotropy in the electrical conductivity that correlates with the surface morphology of the film. This anisotropy was evident in the resistance measurements along the in-plane lateral and vertical directions, which aligned well with our simple model. The results emphasize the significance of film morphology in determining the film’s electrical properties. This study contributes to the understanding of the physical properties of Pt films fabricated via oblique angle deposition and offers valuable insights for designing nanoporous films for various applications.

Shielded Pair Method for Beam Screen Surface Resistance Measurement at Cryogenic Temperature

The shielded pair resonator method is a useful tool in the measurement of accelerator components, such as the beam screens used in the Large Hadron Collider (LHC), the High-Luminosity (HL) LHC, or future accelerators. It can measure the resistive losses at several frequency points by separating the resistive losses on the sample from other sources of losses. We built a new resonator to be inserted into a superconducting dipole magnet (peak magnetic field of 9.5 T) and to measure the surface resistance of beam screens, such as LHC beam screens coated with amorphous carbon (a-C). The device can measure surface resistance at any temperature between 4.2 K and 300 K, in the frequency range of 400 MHz to 1600 MHz. We conducted the first surface resistance measurements of two a-C coated beam screens at 4.2 K and showed that the 200 nm to 400 nm titanium underlayer plus 50 nm a-C only has a limited effect on the surface resistance. This first result supports the choice of this coating as baseline for the HL-LHC triplets magnets upgrade. The resonator will have an important role in the characterization of next-generation beam screens, such as a beam screen with laser-engineered surface structure (LESS). Further measurements of the LHC beam screen in the presence of magnetic fields up to 9.5 T and throughout the full temperature range are going to be reported separately.

Quantifying the Domino Effect of Septoplasty on Eustachian Tube Function and Nasal Resistance in Patients With Chronic Otitis Media: A Cross-Sectional Study.

Background Eustachian tube dysfunction is characterized by insufficient dilation, leading to secondary pathologies in the middle ear. By comparing pre- and post-operative grades of Eustachian tube functionand nasal resistance measurements, this study seeks to determine if septoplasty can improve Eustachian tube function in cases where nasal septal deviation is likely to cause mechanical dysfunction. We also aim to validate the JainBhalerao endoscopic classification of nasal septal deviation by assessing its utility in identifying septal deviations at a higher risk of causing Eustachian tube dysfunction. The ultimate goal is to establish guidelines for aural indications of septoplasty in treating Eustachian tube dysfunction-related middle ear disorders. Material and methods This prospective observational study was carried out from 1stJune 2022 to 31st March 2024 in the Department of Otorhinolaryngology at Acharya Vinoba Bhave Rural Hospital, involving 66 patients diagnosed with chronic otitis media and a deviated nasal septum with Eustachian tube dysfunction. Pre-operative and post-operative improvement in Eustachian tube function and Nasal resistance and their correlation werestudied using dynamic slow-motion video endoscopy and active anterior rhinomanometry, respectively. Statistical analysis included the chi-square test. Results Sixty-six patients diagnosed with chronic otitis media and deviated nasal septum with Eustachian tube dysfunction included in this study had a mean age of 35.6 years with 43 (65.2%) male predominance. Gross luminal narrowing and discrepancy of the volume of both nasal cavities led to higher degrees of Eustachian tube dysfunction due to pressure drop on the affected side, as observed in types 6, 7, and 8 as per Jain Bhalerao classification of deviated nasal septum. Nasal resistance measured using active anterior Rhinomanometry (Rhinodebitometry) showed a positive association of severity of nasal resistance in the types 6, 7, and 8 DNS of the Jain Bhalerao classification of deviated nasal septum. It demonstrated an improvement in the grade of Eustachian tube function and nasal resistance post-septoplasty. Conclusion The deviated nasal septum is one of the causes of Eustachian tube dysfunction and increased nasal resistance. Certain types of DNS are adversely associated with the causation of greater degrees of Eustachian tube dysfunction of mechanical type. Nasal septal deviation correction improved Eustachian dysfunction and nasal resistance after septoplasty.

Conductive, injectable, and self-healing collagen-hyaluronic acid hydrogels loaded with bacterial cellulose and gold nanoparticles for heart tissue engineering

The increasing demand for advanced biomaterials in nerve tissue engineering presents numerous challenges due to the complexity of nerve tissues and the need for materials that can accurately replicate their intricate structure and function. In response, this study introduces a novel injectable hydrogel that is thermosensitive, self-healing, and conductive, offering promising potential for heart and nerve tissue engineering applications. The hydrogel is based on collagen and hyaluronic acid functionalized with 3-aminopropyl-triethoxysilane (APTES)-grafted oxidized bacterial cellulose and gold nanoparticles (~50 nm). Rheological analysis reveals a substantial enhancement in the elastic modulus of the collagen-hyaluronic acid matrix with the incorporation of bacterial cellulose/gold nanoparticles, improving by an order of magnitude at 1 % strain. This improvement comes with a slight decrease in gelation temperature, from 36 °C to 32 °C. Besides thermo-sensitivity, the nanocomposite hydrogel exhibits a remarkable self-sealing response (about 80 % effectiveness) due to reversible physical crosslinking. Electrical spatial resistance measurements on human embryonic stem cell-derived cardiomyocytes-loaded hydrogels yield a value of ~0.1 S/m, which is suitable for electrical stimulation. In vitro extracellular field potential measurements also affirm the hydrogel's potential as an injectable scaffold for heart tissue engineering, i.e., the electrically stimulated human stem cells exhibit 47 beats per minute with a cell discharge (depletion) of 5.47 μv. A rapid gel formation in the physiological temperature (about 2 min) and high H9C2 cytotoxicity (viability of >90 % after 72 h incubation) is attainable. The developed collagen-based nanocomposite hydrogel offers an injectable, thermosensitive, and self-healing biomaterial platform for nerve or myocardium regeneration.

Comprehensive Study of Mechanical, Electrical and Biological Properties of Conductive Polymer Composites for Medical Applications through Additive Manufacturing.

Conductive polymer composites are commonly present in flexible electrodes for neural interfaces, implantable sensors, and aerospace applications. Fused filament fabrication (FFF) is a widely used additive manufacturing technology, where conductive filaments frequently contain carbon-based fillers. In this study, the static and dynamic mechanical properties and the electrical properties (resistance, signal transmission, resistance measurements during cyclic tensile, bending and temperature tests) were investigated for polylactic acid (PLA)-based, acrylonitrile butadiene styrene (ABS)-based, thermoplastic polyurethane (TPU)-based, and polyamide (PA)-based conductive filaments with carbon-based additives. Scanning electron microscopy (SEM) was implemented to evaluate the results. Cytotoxicity measurements were performed. The conductive ABS specimens have a high gauge factor between 0.2% and 1.0% strain. All tested materials, except the PA-based conductive composite, are suitable for low-voltage applications such as 3D-printed EEG and EMG sensors. ABS-based and TPU-based conductive composites are promising raw materials suitable for temperature measuring and medical applications.

Demonstrating the principal mechanism of action of medical devices intended for vaginal use on reconstructed human vaginal epithelium: the case of two hyaluronic acid-containing devices

Regulation (EU) 2017/745 on medical devices (MDR) has significantly modified the rules to be adopted for MD qualifications and classification. New requirements require robust evidence on mechanisms of action (MoAs) that cannot be produced by existing common EU or ISO standards. Therefore, on a “case-by-case basis,” a new evidence-based non-clinical approach to MD qualification must be defined. In this study, an in vitro experimental approach is described to assess the physicochemical and mechanical MoA of two hyaluronic acid (HA)-based medical devices: Mucogyne® Gel and Mucogyne® Ovule for vaginal use. They both act as moisturizers and lubricants as well as a healing adjuvant by promoting the continued moisture of the vulvovaginal area. The MoA of these two products has been demonstrated by using a 3D reconstructed human vaginal epithelium (HVE) model in a homeostatic physiological state and in stressed conditions. Film forming and persistency properties were assessed on intact HVE tissues by caffeine permeation assay and Lucifer Yellow (LY) localization on HVE vertical sections. Healing properties were assessed on injured HVE tissues by trans-electrical epithelial resistance (TEER) measurements associated with histo-morphological analysis (H&amp;amp;E), and moisturizing efficacy was evaluated on HVE tissues cultured in dry conditions by histomorphological analysis (H&amp;amp;E) and aquaporin 3 (AQP3) expression and localization by immunohistochemistry (IHC). Using the same “dry” HVE model, the non-pharmacological action of the two products was addressed by CD44 (hyaluronic acid receptor) expression and localization. The results suggest that in vitro evaluations can provide robust results on a human-relevant experimental model for the intended use of the products and supports clinical data with mechanistic information which may not be achieved with in vivo studies but are particularly important for product qualification. The results also underline the specific relative efficacy of the mechanisms investigated for Mucogyne® Gel and Mucogyne® Ovule in line with their different formulation types (respectively, hydrophilic and lipophilic) that influence the action of the active ingredient HA. The present in vitro non-clinical evaluation of HVE combined with clinical investigation data obtained in women explain why Mucogyne MDs provide significant benefits in various physiological or pathological situations, including vaginal dryness and healing.

Tailoring N, N, N‐trimethyl chitosan nanospheres as an efficient drug carrier to overcome endothelial barrier

AbstractEndothelial barriers, integral components of tissue barriers, are densely packed with adherens junction and tight junction proteins, hindering the passage of drugs to target sites. Herein, a novel nanosphere comprising N, N, N‐trimethylated chitosan (TMC), with the size of 51 ± 8 nm and zeta potential of 13.2 ± 5.3 mV, has been engineered as a drug carrier to facilitate the transport of hydrophobic drugs, that is, curcumin, across endothelial barriers efficiently. The effects of pH value and temperature on the release kinetics of curcumin from TMC nanospheres have been studied. In addition, the transportation of TMC nanospheres across an in vitro endothelial barrier was evaluated over a 72‐h period. The integrity of the in vitro endothelial barrier was assessed before and after the transport of TMC nanospheres by using transepithelial electrical resistance measurements and immunofluorescence staining of tight junction proteins. The results reveal that TMC nanospheres significantly enhance the transport of curcumin across the endothelial barrier, with approximately 30% of curcumin released as compared to less than 3.3% across the barrier without the assistance of TMC nanospheres. This investigation underscores the potential of small‐sized TMC nanospheres to enhance the transport of hydrophobic drugs across endothelial barriers.

Coupling effects of micro/nano-scale surface modification and electric current application on fouling resistance and heat transfer

The principle of saving energy and converting waste heat into valuable resources is a core concept. Heat exchange systems are significantly compromised by microbial fouling, which impedes heat transfer and increases energy consumption. This study investigated the coupling effects of micro/nano-scale surface modifications and the application of electric currents as a novel approach to inhibit microbial fouling. Smooth copper surface, electrochemical deposition (ECD) surface, and Nickel-Phosphorus-Polytetrafluoroethylene (Ni-P-PTFE) modified surface were tested and compared. Firstly, we analyzed the average heat transfer coefficient under clean conditions, taking into account different surface characteristics. Then, we employed a series of fouling experiments to evaluate the anti-biofouling performance of smooth copper surfaces, ECD surfaces, and Ni-P-PTFE surfaces. The assessment involved flow cytometry, Scanning Electron Microscopy (SEM) and measurements of thermal resistance. Finally, we investigated the effect of external electric current on microbial fouling mitigation. Results show that the ECD surface exhibited an enhanced heat transfer and a poor fouling resistance, while the Ni-P-PTFE surface demonstrated an excellent fouling resistance and a minimal increase in thermal resistance. The application of a low direct current density at 0.51 mA/cm² significantly reduced microbial viability on all surfaces. A higher electric current can further inhibit microbial adhesion and proliferation, enhancing the anti-fouling capability of the surfaces. Compared to surfaces without electric current, the smooth copper surface, ECD, and Ni-P-PTFE surfaces at 5.1 mA/cm² displayed a reduction in thermal resistance by 45.7%, 36.8%, and 38.1%, respectively. At 51 mA/cm², the reduction in thermal resistance for smooth copper surface, ECD, and Ni-P-PTFE surfaces was 75.7%, 78.2%, and 57.1%, respectively. This comprehensive study has validated the potential of combining micro/nano-scale surface modifications with electric current application as an effective strategy for enhancing heat transfer efficiency and anti-fouling properties of heat exchange systems.

A Simple Procedure to Obtain the Grounding Resistance Measurement of Very Large and Urban Electrodes by a Modified Fall-of-Potential Method

The measurement of the grounding resistance of grounding grids in large installations as well as grounding electrodes in urban areas is addressed in this article. The resistance value is obtained using a three-pin array by measuring the fall-of-potential on the ground surface. The resistance measured by this method is adjusted to its true value using a correction factor that aligns the measured resistance with the actual value. The proposed measurement method obtains correct values of the grounding resistance even when the auxiliary and potential electrodes of the tree-pin array are close to the electrode to be measured. Thus, it can be applied to large electrodes as well as electrodes in urban areas. Several simulated examples are used to illustrate the method, and some real cases with field measurements are presented for a final validation of the method.

Laser micro/nano structuring of three-dimensional porous gradient graphene: Advanced heater for antibacterial surfaces and ion-selective electrode for sweat sensing

The development of three-dimensional (3D) gradient porous graphene (GPG) patterns, leveraging the remarkable properties and unique structure of graphene, has garnered considerable attention owing to their excellent electrochemical and electrothermal performances. Among the numerous graphene synthesis methods, laser-induced graphene (LIG) stands out as an eco-friendly and practical approach for creating patterned graphene structures on commercial films, with synthetic details varying depending on the application. Unlike conventional LIG with uniform geometric characteristics, we developed an innovative approach for circular line-scribed ultraviolet (UV)-LIG patterning; these approaches utilize a high overlapping factor and low power to achieve uneven graphitization. A comprehensive analysis of the 3D GPG was conducted via specific surface area measurements, contact angle analyses, sheet resistance measurements, X-ray photoelectron spectroscopy, and Raman spectroscopy. These 3D GPG structures exhibit large surface areas, low sheet resistance, and superior ion transport, thus improving heater and ion-selective electrode (ISE) performances. The fabricated 3D GPG heaters were successfully applied to antibacterial surfaces, and the ISEs were applied in a sweat sensor was demonstrated owing to the remarkable combination of high surface area, low electrical resistance, and unique 3D porous structure.

Protective effects of Parkin knockout on asthma-induced changes in juvenile mice: inflammation, airway resistance, and oxidative stress

Objective This study aimed to explore the effects of Parkin (Prkn) knockout in a juvenile mouse model of asthma. Methods Prkn knockout (KO) and wild type (WT) mice were utilized to establish a juvenile mouse asthma model. The asthma model involved exposure to hyperoxia/ovalbumin (OVA), encompassing hyperoxia from postnatal day 1 (P1) to P7, sensitization on P21 and P28, and challenge from P36 to P42. Room air/phosphate-buffered saline (PBS) served as the control condition. Following airway resistance measurement, bronchoalveolar lavage fluid (BALF) was collected for cellular analysis, and lung tissues were subjected to histological examination and oxidative stress assessment. Serum levels of ovalbumin-specific immunoglobulin E (IgE), total IgE, interleukin-4 (IL-4), IL-5, and IL-13 were quantified using enzyme-linked immunosorbent assay (ELISA). Results WT mice exposed to hyperoxia/OVA showed decreased body weight and increased airway resistance compared to those exposed to control condition. Conversely, KO mice exhibited increased body weight under asthma conditions. KO mice with asthma had reduced total cell counts, along with lower levels of lymphocytes, eosinophils, and neutrophils, compared to WT asthma mice. Histological assessment showed attenuated inflammation and reduced collagen deposition in KO mice relative to WT mice, with lower serum levels of inflammatory markers and improved lung oxidative stress profiles. No significant differences were observed between KO and WT mice under room air/PBS conditions. Conclusions Parkin knockout in juvenile mice mitigates asthma-related alterations in airway resistance, histopathological changes, inflammation status, and oxidative stress. These findings highlight a protective role of Parkin deficiency against asthma-associated pathologies.