Potential Measurements Research Articles

Measurement of Electrostatic Potentials in Semiconductor Devices by Off-axis Electron Holography

Measurement of Electrostatic Potentials in Semiconductor Devices by Off-axis Electron Holography

Effect of Annealing after Casting and Cold Rolling on Microstructure and Electrochemical Behavior of High-Entropy Alloy, Cantor

High-entropy alloys (HEAs), a relatively new class of materials, have attracted significant attention in materials science owing to their unique properties and potential applications. High entropy stabilizes the phase of a solid solution over a wide range of chemical compositions, yielding unique properties superior to those of conventional alloys. Therefore, this study analyzed the microstructure and electrochemical behavior of HEAs (Cantor) to evaluate their corrosion resistance, according to their manufacturing process (casting, cold rolling, and annealing). The microstructural morphologies and sizes were analyzed using electron backscatter diffraction. The electrochemical behavior was examined using open circuit potential measurements, electrochemical impedance spectroscopy, potentiodynamic polarization tests, and critical pitting temperature measurements using a potentiostat. The casting process formed a nonuniform microstructure (average grain size = 19 μm). The cold rolling process caused the formation of fine grains (size = 4 μm). A uniform microstructure (grain size > 151 μm) was formed after heat treatment. The corrosion resistance of the HEAs was determined from the passivation layer formed by Cr oxidation. These microstructural differences resulted in variations in the electrochemical behavior. Microstructural and electrochemical analyses are crucial because HEAs have diverse potential applications. Therefore, this study contributes to future improvements in HEA manufacturing processes.

Evaluation of hospital-onset bacteraemia and fungaemia in the USA as a potential healthcare quality measure: a cross-sectional study

BackgroundHospital-onset bacteraemia and fungaemia (HOB) is being explored as a surveillance and quality metric. The objectives of the current study were to determine sources and preventability of HOB in hospitalised...

Reproductive Toxicity Caused by Zearalenone on Animals and Its Possible Interventions

Zearalenone (ZEN) is a mycotoxin that is usually found in moldy grains. ZEN causes reproductive toxicity to domestic animals by interfering with follicular and embryonic development, reducing sperm vitalityand destroying the homeostasis of endogenous hormones, leading to reproductive system diseases such as abortion, ovarian dysfunctionand stillbirth. The reproductive damage caused by zearalenone is mainly attributed to the factors as follows: (1) interaction with estrogen receptor; (2) induction of oxidative stress; (3) induction of apoptosis, necrosis, autophagyand iron prolapse and (4) interference with cell replication cycle. Natural compounds and micro-nutrients have the potential to alleviate the oxidative stress caused by ZEN. In addition, some microorganisms and enzymes have also shown good detoxification effects. Therefore, in this review, we focus on the damage caused by ZEN on animal gamete development and embryonic development, its molecular mechanismsand suggested some potential mitigation measures for the prevention of ZEN-induced toxicity to provide information for preventing toxicity associated with ZEN as well as serve as a foundation for further development of drug candidates for the treatment of ZEN induced damage.

Effect of Surfactants on 1,2-Dichloroethane-in-Water Droplet Impacts at Electrified Liquid-Liquid Interface

In this work, we used the electrified liquid-liquid interface (eLLI) to study the fusion of DCE-in-water organic droplets (soft particles) upon coming into contact with the soft interface. Our focus was to define the effect of the neutral (1-tetradodecanol) and ionic (cetyltrimethylammonium bromide and sodium dodecylsulfonate) surfactants that stabilize the colloidal solution on the electroanalytical output of the impact events. The electrochemically and interfacially active salt used in our work (tetramethylammonium tetrakis(4-chlorophenyl)borate) was always initially dissolved in the organic phase droplets. When the potential drop at the interface was set below the formal Galvani potential of the tetramethylammonium cation ion transfer, we observed ionic current events upon the fusion of the droplets at the eLLI, as studied by chronoamperometry. This phenomenon was found to be severely affected by the surfactants. Our system was investigated with several methods, including cyclic voltammetry, chronoamperometry, interfacial tension measurements, and finally zeta potential and droplet size distribution measurements based on dynamic light scattering.

Photocatalytic Performance of ZnO@ZnS Core–Shell Heterostructures for Malachite Green and Rhodamine B Dye Degradation

The one‐step green synthesis of wide band gap zinc oxide@zinc sulfide (ZnO@ZnS) core–shell nanostructures offers promising prospects in wastewater treatment. These nanostructures exhibit a porous nature crucial for effective dye adsorption, as evidenced by Brunauer‐Emmett‐Teller (BET) and microscopic characterization. The synthesized material demonstrates high stability and minimal agglomeration, verified through BET analysis and zeta potential measurements. X‐ray powder diffraction confirms the presence of ZnO and ZnS phases. Transmission electron microscopy reveals the development of porous nanorods on the core surface, maximizing the surface area for dye adsorption. In wastewater treatment, the nanostructures exhibit notable performance, degrading 90% of malachite green and 50% of rhodamine B dyes within 120 min under normal conditions. Detailed discussions delve into the degradation mechanism, elucidating the major species responsible for the process. This study underscores the potential of ZnO@ZnS nanostructures in efficient organic pollutant removal, marking a significant advancement in environmental remediation.

Engineering polyvinylidene fluoride membranes using charge tunable dendrimer polyamidoamine to enable microporous membranes for protein separation

Dendrimers are structurally precise molecules, whose peripheral layer provides ample sites for anchoring functional groups of different charges and charge densities. This characteristic renders them capability of providing numerous target functional groups on the surface of filtration membranes when modified by dendrimers. Consequently, there has been a growing interest in dendrimer-modified membranes. In this study, we investigated the engineering of polyvinylidene fluoride (PVDF) membranes using polyamidoamine (PAMAM) dendrimers anchoring different functional groups to tune the charges and charge density of membranes to enable microporous membranes for separation of charged macromolecules. PVDF membranes were functionalized by grafting PAMAM-G3.0 (generation 3) dendrimers with amine groups onto their surfaces and internal surfaces of membrane pores. Subsequently, the peripheral functional groups of dendrimers on the membranes were replaced by carboxyl groups, quaternary ammonium groups, or sulfonic acid groups for charges of different nature and densities. Surface chemical properties, electrical properties, and morphology were characterized using various techniques, including attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and surface zeta potential measurement. The filtration performance of both PVDF and modified membranes was evaluated using polyethylene oxide (PEO), polyacrylic acid (PAA), and whey protein filtration. Among the modified membranes, the G3PA membranes, with carboxyl functional groups, exhibited the most effective whey protein separation performance. The whey protein rejection and permeate flux of the G3PA membranes were 79 % and 30.3 LMH, respectively. As a comparison, the whey protein rejection and permeate flux of the pristine PVDF membranes were 58.9 % and 15.3 LMH, respectively.

Low Light at Specific Growth Stage Affects Photoassimilates Transportation, Seed Quality and Yield in Brassica napus L.

ABSTRACTIn many parts of the world, solar radiation has decreased during the past 50 years due to industrialisation‐induced elevations in air aerosols which has negatively impacted crop productivity. Climate change threatens rapeseed (Brassica napus L.) production due to shade stress caused by reduced light radiation. However, studies on how shade affects photosynthetic mechanisms in rapeseed (leaves and pod wall) are not well documented. Understanding the mechanisms of shade on yield formation in rapeseed is important for breeding shade‐tolerant rapeseed varieties and optimising agricultural management practices in low‐light areas. Therefore, this study assesses the impacts of ‘global dimming’ simulated by shading at a specific period on rapeseed's photosynthetic behaviour, yield and seed quality. A two‐factor split‐plot design was arranged with three shading treatments (CK, FS and PS) and two hybrid genotypes (Chuannong and Zhongyouza) of rapeseed. We observed that shading at the flowering stage (FS) significantly inhibited the leaf area index, chlorophyll content, photosynthetic efficiency and enzymatic activities of both genotypes. Besides that, shading at pod development stage (PS) substantially declined the pod photosynthetic characteristics and transportation of carbohydrates towards economic organ (seeds) which directly decreased the yield of rapeseed. We found that PS treatment remarkably declined the oil content of both genotypes. According to the results, the photosynthetic capacity of rapeseed pod wall had a greater impact on yield and seed quality than leaves. Therefore, improving the photosynthetic capacity and material transport efficiency of the pod wall is a potential measure to increase the yield of rapeseed under shade stress. This study provides a new insight into the effects of shade on rapeseed production and provides a valuable reference for rapeseed breeding techniques to develop high‐yielding genotypes by enhancing the photosynthetic efficiency of rapeseed pod wall in low‐light conditions.

Ion-selectivity of galvanic corrosion products formed in multi-material gaps under atmospheric corrosion conditions with anti-freezing salts

Several multi-materials, which are joints of high-strength steels and lightweight materials such as aluminum alloy and carbon fiber reinforced thermoplastic, were subjected to the cyclic corrosion test for simulating atmospheric corrosion of automotive bodies and outdoor exposure tests. The ion-selectivity of the corrosion products formed in the multi-material gaps was examined by a membrane potential measurement. The corrosion products of all examined joints showed anion-selectivity rather than cation-selectivity. Corrosion products formed in joint gaps were less effective in preventing the progression of galvanic corrosion, suggesting that sufficient atmospheric corrosion protection is required for the use of multi-materials.

Gadolinium-Based NMR Spin Relaxation Measurements of Near-Surface Electrostatic Potentials of Biomolecules.

NMR spectroscopy is an important tool for the measurement of the electrostatic properties of biomolecules. To this point, paramagnetic relaxation enhancements (PREs) of 1H nuclei arising from nitroxide cosolutes in biomolecular solutions have been used to measure effective near-surface electrostatic potentials (ϕENS) of proteins and nucleic acids. Here, we present a gadolinium (Gd)-based NMR method, exploiting Gd chelates with different net charges, for measuring ϕENS values and demonstrate its utility through applications to a number of biomolecular systems. The use of Gd-based cosolutes offers several advantages over nitroxides for ϕENS measurements. First, unlike nitroxide compounds, Gd chelates enable electrostatic potential measurements on oxidation-sensitive proteins that require reducing agents. Second, the large electron spin quantum number of Gd (7/2) results in notably larger PREs for Gd chelates when used at the same concentrations as nitroxide radicals. Thus, it is possible to measure ϕENS values exclusively from + and - charged compounds even for highly charged biomolecules, avoiding the use of neutral cosolutes that, as we further establish here, limits the accuracy of the measured electrostatic potentials. In addition, the smaller concentrations of cosolutes required minimize potential binding to sites on macromolecules. Fourth, the closer proximity of the paramagnetic center and charged groups within Gd chelates, in comparison to the corresponding nitroxide compounds, enables more accurate predictions of ϕENS potentials for cross-validation of the experimental results. The Gd-based method described here, thus, broadens the applicability of studies of biomolecular electrostatics using solution NMR spectroscopy.

Magnetic Resonance Imaging as a Potential Optic Nerve Area Measurement in Optic Nerve Atrophy Diagnosis

Magnetic Resonance Imaging as a Potential Optic Nerve Area Measurement in Optic Nerve Atrophy Diagnosis

Preparation and Mechanism of Shale Inhibitor TIL-NH2 for Shale Gas Horizontal Wells.

In this study, a new polyionic polymer inhibitor, TIL-NH2, was developed to address the instability of shale gas horizontal wells caused by water-based drilling fluids. The structural characteristics and inhibition effects of TIL-NH2 on mud shale were comprehensively analyzed using infrared spectroscopy, NMR spectroscopy, contact angle measurements, particle size distribution, zeta potential, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The results demonstrated that TIL-NH2 significantly enhances the thermal stability of shale, with a decomposition temperature exceeding 300 °C, indicating excellent high-temperature resistance. At a concentration of 0.9%, TIL-NH2 increased the median particle size of shale powder from 5.2871 μm to over 320 μm, effectively inhibiting hydration expansion and dispersion. The zeta potential measurements showed a reduction in the absolute value of illite's zeta potential from -38.2 mV to 22.1 mV at 0.6% concentration, highlighting a significant decrease in surface charge density. Infrared spectroscopy and X-ray diffraction confirmed the formation of a close adsorption layer between TIL-NH2 and the illite surface through electrostatic and hydrogen bonding, which reduced the weakly bound water content to 0.0951% and maintained layer spacing of 1.032 nm and 1.354 nm in dry and wet states, respectively. Thermogravimetric analysis indicated a marked reduction in heat loss, particularly in the strongly bound water content. Scanning electron microscopy revealed that shale powder treated with TIL-NH2 exhibited an irregular bulk shape with strong inter-particle bonding and low hydration degree. These findings suggest that TIL-NH2 effectively inhibits hydration swelling and dispersion of shale through the synergistic effects of cationic imidazole rings and primary amine groups, offering excellent temperature and salt resistance. This provides a technical foundation for the low-cost and efficient extraction of shale gas in horizontal wells.

Synthesis of Nanoflowers using Garcinia gummi-gutta Leaf Extract via Green Route for Enhanced Antifungal and Anti-cancerous Activities

Due to its envisaged relevance in nanomedicine and materials research, the bio-engineering of nanoparticles (NPs) is becoming progressively more promising. Compared to physical and chemical processes, green synthesis produces NPs that are less hazardous to the environment. The usage of phytochemicals in Garcinia gummi-gutta (L.) leaf extract (GGL) in the bio-reduction of GGL-Ag NPs with potential antifungal and anti-cancerous activities was the main focus of the current study. UV-vis spectrophotometry at 442 nm verified the synthesized GGL-Ag NPs. The average diameters of the synthesized GGL-Ag NPs were determined by scanning electron microscopy (SEM and zeta-sizer studies to be 166.69 nm and 148.2 nm, respectively. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) examinations of the GGL-Ag NPs confirmed the crystalline nature and the elemental constitution of the NPs. Additionally, the synthesized GGL-Ag NPs' FTIR spectra demonstrated the presence of Phyto components acting as capping agents. Zeta potential measurements (-26.2± 4.13 mV) authenticated the stability of the synthesized GGL-Ag NPs. Antimicrobial activity testing of the GGL-Ag NPs demonstrated considerable suppression against Candida tropicalis and Candida albicans at a dose of 100 µg/ml and 60 µg/ml. Additionally, the synthesized GGL-Ag NPs have demonstrated considerable cytotoxic effects on the Hep-G2 cell line. The current study results show that GGL- Ag NPs may be produced at a low cost and with minimal environmental impact for nanobiotechnology and biomedicine usage.

Illuminating Pathways to Dynamic Nanotribology: Light-Mediated Active Control of Interfacial Friction with Nanosuspensions.

Active control of nanotribological properties is a challenge. Materials responsive to external stimuli may catalyze this paradigm shift. Recently, the nanofriction of a thin film is modulated by light, ushering in phototribology. This frontier is expanded here, by investigating photoactive nanoparticles in lubricants to confer similar functionality to passive surfaces. Quartz-crystal microbalance (QCM) is employed to assess the phototribological behavior of aqueous suspensions of titanium dioxide nanoparticles. A comparison of dark and illuminated conditions provides the first demonstration of tuning the interfacial friction in solid-nanosuspension interfaces by light. Cyclic tests reveal reversible transitions between higher (dark) and lower friction (illuminated) regimes. These transitions are underpinned by transient states with surface charge variations, as confirmed by Zeta potential measurements. The accumulated surface charge increases repulsion within the system and favors sliding. Upon cessation of illumination, the system returns to its prior equilibrium state. These findings impact not only nanotribology but nanofluidics and nanorheology. Furthermore, the results underscore the need to consider light-induced effects in other scenarios, including the calculation of activity coefficients of photoactive suspensions. This multifaceted study introduces a new dimension to in operando frictional tuning, beckoning a myriad of applications and fundamental insights at the nanoscale.

Local cochlear mechanical responses revealed through outer hair cell receptor potential measurements

Sensory hair cells, including the sensorimotor outer hair cells, which enable the sensitive, sharply tuned responses of the mammalian cochlea, are excited by radial shear between the organ of Corti and the overlying tectorial membrane. It is not currently possible to measure directly in vivo mechanical responses in the narrow cleft between the tectorial membrane and organ of Corti over a wide range of stimulus frequencies and intensities. The mechanical responses can, however, be derived by measuring hair cell receptor potentials. We demonstrate that the seemingly complex frequency- and intensity-dependent behavior of outer hair cell receptor potentials could be qualitatively explained by a two degrees of freedom system with local cochlear partition and tectorial membrane resonances strongly coupled by the outer hair cell stereocilia. A local minimum in the receptor potential below the characteristic frequency should always be observed at a frequency where the tectorial membrane mechanical impedance is minimal, i.e., at the presumed tectorial membrane resonance frequency. The tectorial membrane resonance frequency might, however, shift with stimulus intensity in accordance with a shift in the maximum of the tectorial membrane radial mechanical responses to lower frequencies, as observed in experiments.

In vitro and in silico investigations of the pro-apoptotic activity of Opuntia ficus-indica cladode extracts against K562 cells

Abstract Objectives Cladodes of Opuntia ficus-indica (OFI) are thought to be an excellent source of bioactive compounds, making them an aspirant for the manufacture of health-promoting compounds. This study aims at exploring the pro-apoptotic effects of spiny and thornless OFI cladode extracts on the human immortalized myelogenous leukemia cell line (K562). Methods The ethanol extraction method was used for preparing cladode extract. Cytotoxicity was evaluated by MTT assays. Membrane permeability/damage was detected by annexin V-binding assays, and mitochondrial damage/alteration was detected by mitochondrial membrane potential measurements. The protein expression quantities of Bax and Bcl-2 were assessed by Western blotting. The pro-apoptotic potentials of the main spiny and thornless OFI extract constituents were investigated structurally and mechanistically using protein–ligand docking and interaction profiling. Results Spiny OFI extract displayed a stronger cytotoxic effect than thornless OFI extract on K562 cells. In silico findings agreed with the pro-apoptotic action observed in vitro. Conclusions Finally, our findings imply that OFI extracts cause apoptosis in K562 cells in order to have anti-cancer effects.

Surface Chemistry of Cytosporone-B Incorporated in Models for Microbial Biomembranes as Langmuir Monolayers.

Cytosporone-B, a polyketide renowned for its antimicrobial properties, was integrated into Langmuir monolayers composed of dipalmitoylphosphoethanolamine (DPPE) and dioleoylphosphoethanolamine (DOPE) lipids, effectively emulating microbial cytoplasmic membranes. This compound exhibited an expansive influence on DPPE monolayers while inducing condensation in DOPE monolayers. This led to a notable reduction in the compressibility modulus for both lipids, with a more pronounced effect observed for DPPE. The heightened destabilization observed in DOPE monolayers subjected to biologically relevant pressures was particularly noteworthy, as evidenced by surface pressure-time curves at constant area. In-depth analysis using infrared spectroscopy at the air-water interface unveiled alterations in the alkyl chains of the lipids induced by cytosporone-B. This was further corroborated by surface potential measurements, indicating a heightened tilt in the acyl chains upon drug incorporation. Notably, these observed effects did not indicate an aggregating process induced by the drug. Overall, the distinctive impact of cytosporone-B on each lipid underscores the importance of understanding the nuanced effects of microbial drugs on membranes, whether in condensed or fluid states.

Efficacious sensing and elimination of iron ions from aqueous medium by polyethylenimine functionalized carbon dot

In the present work, Iron (Fe) ions are detected and removed from an aqueous medium using a green emissive polyethylenimine functionalized carbon dots (GPC), which are produced hydrothermally and have high adsorption efficiency and sensitivity. As prepared, GPC uses an adsorption approach to remove iron ions and a Turn-Off mechanism to detect iron ions. A UV-Vis and photoluminescence spectroscopy are used to evaluate the results of several experiments, including those involving the interference of other ions, changing the concentration of metal ions, pH, reaction time, and the dosage of adsorbent in the sensor, in an attempt to achieve high sensitivity (with a lower limit of detection of 0.08 ppm) and high adsorption efficiency of approximately 98 % (8 µM of Fe and 1 ppm of GPC) towards iron ions. The isotherm and kinetic analyses of adsorption show that pseudo-second-order kinetics and Freundlich isotherm suits the experimental data better. With a removal percentage of roughly 89 percent after three cycles, desorption analysis highlights its regeneration efficiency. The mechanism of adsorption and quenching are extensively investigated; The static and dynamic quenching mechanisms are supported by high static constant value of approximately 23.5 ×103 M and the lifetime decay declination of 2.42 ns, respectively. Zeta potential measurements and XPS analysis are used to examine the electrostatic interaction between GPC and Fe in the adsorption mechanism. Ultimately, the prepared material's contentment results illustrate its potential for practical applicability with five actual water samples.

Sound absorption uncertainty in small reverberation chambers

Manufacturers in the mobility industry typically measure and specify the sound absorption coefficient of materials using a small reverberation chamber according to SAE J2883. These chambers have a 6 to 25 cubic meter volume, use a 1.0 meter x 1.2 meter sample size and report sound absorption in the one-third octave bands from about 400 Hz to 10,000 Hz. This is in contrast to a full-size chamber built to satisfy the requirements of ASTM C423 or ISO 354, which have about a 200 cubic meter volume, use a 2.4 x 2.7 or 3.2 x 3.2 square meter sample size and report sound absorption in one-third octave bands from 100 to 5,000 Hz. Although the room and sample size dimensions scale, many of the factors that contribute to uncertainty in the measurement do not scale. These include relative humidity, temperature, and other physical measurements and if the same instrumentation is used, microphone calibration and measurement uncertainty in the higher frequency range. This paper examines the potential measurement uncertainty in these chambers over the 400 to 10,000 Hz frequency range and compares this to past uncertainty analyses of full-size chambers over a similar frequency range.

Quality measures in primary care skin cancer management: a qualitative study of the views of key informants

ObjectivesThis study explored potential quality measures to improve skin cancer management in primary care settings, and the barriers and facilitators associated with their implementation.DesignSemistructured interviews and qualitative proforma surveys were...