Search

To oxidize trace concentrations of organic contaminants under conditions relevant to surface- and groundwater, air-diffusion cathodes were coupled to stainless-steel cathodes that convert atmospheric O2 into hydrogen peroxide (H2O2), which then was activated to produce hydroxyl radicals (·OH). By separating H2O2 generation from its activation and employing a flow-through electrode consisting of stainless-steel fibers, the two processes could be operated efficiently in a manner that overcame mass-transfer limitations for O2, H2O2, and trace organic contaminants. The flexibility resulting from separate control of the two processes made it possible to avoid both the accumulation of excess H2O2 and the energy losses that take place after H2O2 has been depleted. The decrease in treatment efficacy occurring in the presence of natural organic matter was substantially lower than that typically observed in homogeneous advanced oxidation processes. Experiments conducted with ionized and neutral compounds indicated that electrostatic repulsion prevented negatively charged ·OH scavengers from interfering with the oxidation of neutral contaminants. Energy consumption by the dual-cathode system was lower than values reported for other technologies intended for small-scale drinking water treatment systems. The coordinated operation of these two cathodes has the potential to provide a practical, inexpensive way for point-of-use drinking water treatment.

Accurate parametrization of amino acids is pivotal for the development of reliable force fields for molecular modeling of biomolecules such as proteins. This study aims to assess amino acid electrostatic parametrizations with the polarizable Gaussian Multipole (pGM) model by evaluating the performance of the pGM-perm (with atomic permanent dipoles) and pGM-ind (without atomic permanent dipoles) variants compared to the traditional RESP model. The 100-conf-combterm fitting strategy on tetrapeptides was adopted, in which (1) all peptide bond atoms (-CO-NH-) share identical set of parameters and (2) the total charges of the two terminal N-acetyl (ACE) and N-methylamide (NME) groups were set to neutral. The accuracy and transferability of electrostatic parameters across peptides with varying lengths and real-world examples were examined. The results demonstrate the enhanced performance of the pGM-perm model in accurately representing the electrostatic properties of amino acids. This insight underscores the potential of the pGM-perm model and the 100-conf-combterm strategy for the future development of the pGM force field.

Cupriavidus necator can produce single-cell proteins (SCPs) using electrons produced by hydrogen as energy, oxygen as electron acceptors, and CO2 as carbon sources. Gas fermentation is a process of microbial fermentation that uses gas substrates (such as hydrogen, carbon dioxide, etc.) which faces several challenges, mainly including the low solubility of gas substrates, the danger of hydrogen and oxygen mixing, and the optimization of fermentation conditions. To overcome these challenges, this article explores a variety of strategies—including the design of a self-developed bioreactor—to reduce the risk of static electricity. Without the addition of filler material, the results showed that the maximum cell dry weight (CDW) of 30% secondary seed inoculation was 20.41% higher than that of 10% secondary seed inoculum, and 5.99% higher than that of 20% secondary seed inoculum. Combined with the filler material and with the use of high-efficiency continuous fermentation technology, the average yield of continuous fermentation was 23.31 g/day, while the average yield of batch fermentation was 14.33 g/day. The daily yield of continuous fermentation is 1.63 times that of batch fermentation. These efforts are aimed at improving the efficiency and safety of gas fermentation. [ABSTRACT FROM AUTHOR]

This paper presents a teaching scenario designed to introduce preschool children to electricity, structured around the 5E instructional model (Engage, Explore, Explain, Elaborate, Evaluate). The study involves 18 children from an urban kindergarten with diverse backgrounds and learning needs. Over four weeks, children engage in interactive activities to understand electrical devices, electric current, static electricity, conductors, insulators, electricity generation, and safety. The curriculum integrates interdisciplinary learning, combining literacy and science, and uses hands-on experiments and digital tools to enhance engagement. Activities include constructing simple circuits, experimenting with static electricity, and role-playing. Emphasis is placed on practical applications and safety. Findings highlight the effectiveness of a constructivist approach, where children build understanding through exploration. The study underscores the need for resources, teacher preparedness, and inclusive strategies to address diverse learning needs. This scenario provides insights into effective early childhood science education, emphasizing the potential to build a strong foundation for future learning and curiosity in young children. [ABSTRACT FROM AUTHOR]

Background: This study evaluated the prevalence of sick building syndrome (SBS) in Rasht, Iran, a subtropical climate with wetter cold season city, during the autumn and winter months of 2020, focusing on the effects of noise and ventilation. Methods: A total of 420 residents completed the indoor air climate questionnaire (MM040EA), and a walk-through survey of 45 randomly selected residential units assessed environmental noise, ventilation rate, and luminous conditions. Results: Approximately 38.2% reported SBS symptoms in the past three months. Significant associations were found between SBS and dim light (P-value = 0.012, OR = 2.1, CI = 1.09-4), noise (P-value = 0.031, OR = 1.75, CI = 1.1–2.9), passive smoking (P-value < 0.01, OR = 2.6, CI = 1.22–5.4), static electricity (P-value < 0.01, OR = 3.8, CI = 1.15–12.6), bad air (P-value < 0.01, OR = 4.6, CI = 1.6–13), and high room temperature (P-value = 0.039, OR = 2.6, CI = 1.13–5.95) at α = 0.05. The field survey revealed that 75.5% of units exceeded the national noise threshold of 55 dBA. The average ventilation rate was 20 lit/(p.sec), while 32% of the units reported low or moderate lighting during daytime hours. No significant association was found between the type of interior wall finishing or heating systems and SBS. Stronger correlation was observed between noise and SBS in districts with higher traffic-induced noise. Conclusion: Considering high noise levels in residential areas, local authorities must prioritize noise insulation policies in building design and construction. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A new fluorescent fingerprint powder (DFF‐MMT) was formulated by blending cyclic chalcone dye DFF with montmorillonite (MMT), which can develop latent fingerprints (LFPs) with exceptional resolution and contrast on various surfaces, including ordinary glass, tin foil, marble, LED screens, and materials with distinct colors and fluorescent backgrounds. The fluorescence of DFF‐MMT transforms from orange to bright yellow with LFPs, allowing for a flawless visualization of fingerprints on uneven surfaces or materials with static electricity. Impressively, fingerprints developed by DFF‐MMT can be stored for over 21 months and conveniently duplicated. The developed LFPs by DFF‐MMT still keep high quality under the influence of aquatic condition, illumination and thermal effects. DFF‐MMT also exhibits benefits, such as affordability, real‐time, high‐resolution, high‐contrast development and no damage to DNA, making it an ideal choice for sophisticated criminal investigations. [ABSTRACT FROM AUTHOR]

Static electricity is a phenomenon commonly encountered yet often misunderstood and underestimated in terms of its hazard potential; it continues to challenge the safety and reliability of industrial processes, particularly those involving flammable substances. This paper delves into the critical issue of electrostatic hazards in industrial settings by presenting two flash fire/explosion case studies, one involving biphenyl dust and the other gasoline vapor; both linked to electrostatic discharges. The first case study examines an explosion in a flaker and pack‐out hopper during biphenyl flake manufacturing. The investigation reveals the role of electrostatic charges in the incident and how well‐intentioned equipment changes created warning signs of increased risk that were missed. The second case study discusses a gasoline vapor flash fire, highlighting the common yet overlooked hazard of static electricity during the transfer of flammable liquids. It underscores how common activities involving people can generate sufficient electrostatic charge to ignite flammable vapor–air mixtures in industry. The outcomes of these studies highlight the importance of acting on early warning signs of static electricity and the crucial role of data‐driven diagnostic techniques in addressing and controlling those hazards. By dissecting the intricacies of electrostatic phenomena, safety professionals can formulate actionable strategies to adapt plant operations and prevent hazards from static electricity. The paper advocates for a proactive approach to identifying and mitigating electrostatic risks in industrial settings beginning with process hazard analyses that incorporate static electricity hazards analysis and continues through employee training to ensure that early warning signs are identified, understood, and acted upon. It stresses the need for comprehensive safety measures, including proper grounding and bonding, use of static dissipative materials, and regular maintenance of safety equipment, to prevent incidents. Through these case studies, the paper contributes to understanding of electrostatic hazards in industrial processes and highlights the importance of integrating electrostatic safety measures into routine industrial operations. [ABSTRACT FROM AUTHOR]

Electrical stimulation is effective for various therapeutic applications; however, to increase convenience, it is crucial to eliminate generators and batteries for wireless power transmission. This paper presents a full textile-based body-coupled electrical stimulation (BCES) system designed for wireless electrical stimulation using energy loss from electronic devices and static electricity from physical activity. We developed the BCES socks by knitting conductive threads to ensure stability and comfort. BCES socks generate electric fields ranging from tens to hundreds of millivolts per millimeter, which are sufficient to activate muscle fibers. Experimental and computational analyses confirmed the effective concentration of the electric fields. Human trials demonstrated significant improvements in exercise performance, with a 21.47% increase in calf raise frequency, an 11.97% increase in repetition count, and a 6.25% reduction in muscle fatigue. These results indicate the potential of BCES socks as a practical battery-free solution for enhancing muscle activity and reducing fatigue. [ABSTRACT FROM AUTHOR]

The use of softeners is essential for enhancing laundered fabrics and hair textures after washing. For these, products based on double‐tailed cationic surfactants are used to reduce friction and static electricity, resulting in softer and smoother fibers. These surfactants form lamellar phases in water, which can be turned into vesicles and other bilayer aggregates upon shearing, greatly impacting on the rheological properties of these formulations. This study aims at elucidating how some parameters of the formulation process impact bilayer structures formation and the product rheology, using di(hydrogenated tallow)dimethylammonium chloride (DHTDMAC) aqueous dispersions as model system. Small angle X‐ray scattering (SAXS) analyses revealed lamellar phases starting from 3% DHTDMAC, with a bilayer thickness of 1.90 ± 0.03 nm, indicating significant carbon chain interdigitation. At this concentration (3%), bilayers exhibited a repetition distance of 69 nm, unveiling a behavior close to the one predicted for infinite swelling, in which lamellar structures persisted even at high dilution. Temperature plays a significant role in the rheological behavior, with elevated temperatures favoring vesicle formation, resulting in reduced apparent viscosity due to lower resistance of vesicles to flow. Upon heating, differential scanning calorimetry (DSC) analyses revealed a transition from Lβ (gel) to Lα (fluid) structures between 28 and 41°C, which was further confirmed by X‐ray diffraction (XRD). Both structural and thermotropic features observed were discussed and compared to information reported for a high‐purity grade homologue of DHTDMAC, dioctadecyldimethylammonium chloride (DODAC) mixed with water. These findings deepen the understanding of fabric softener formulation and the impact of bilayer structures formation on their properties, and should be used to optimize new formulations, enhancing their overall performance and sensorial quality. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Laboratory grounding indicates strong professionalism and is mainly implemented in laboratory infrastructure construction and renovation processes, which are quite easy to neglect. The core objectives of the research were to delve into the significance and complexities of proper grounding in university laboratory settings, which included examining the roles of grounding in enhancing safety, protecting equipment, and maintaining the accuracy of the experimental results. This study raised awareness of the often overlooked but critical aspects of grounding in laboratories. [Methods] To achieve the aforementioned objectives, this paper first discussed the various types of grounding required in a laboratory setting and then reviewed the essential functions, such as protection against electric shocks, prevention of electromagnetic interference, stabilization of equipment operation, and dissipation of static electricity. The protective function of grounding, i.e., to prevent electric shocks and damage to equipment by diverting currents to the earth, was highlighted. The importance of grounding in shielding sensitive electronic devices from electromagnetic interference and its vital improvement of the signal-to-noise ratio of precision instruments, which could compromise the quality and reliability of data obtained from experiments, was also underscored. Risk analysis was conducted to illustrate the potential consequences of improper grounding, including power instability, increased likelihood of electrocution, fire and explosion hazards, damage to instruments, and data distortion. This study proposed the implementation of a comprehensive grounding design strategy for the Analysis & Testing Center at North China Electric Power University, which might mitigate these risks. This comprehensive grounding design strategy involved the use of local equipotential bonding boxes, complex grounding networks, and specific engineering techniques to reduce ground resistance to meet the stringent requirements of high-precision instruments. [Results] Implementing grounding strategies at the Analysis & Testing Center resulted in a significant reduction in ground resistance by employing advanced grounding techniques. In this study, a deep hole was drilled by adding conductive materials. A ground resistance of <0.5 Ω was achieved. This result not only satisfied the strict criteria set for sensitive equipment but also contributed to a safer working environment and more accurate data collection. Laboratory checklists converted the professional issues into actionable confirm items, such as "Yes or No". The use of the laboratory checklists in the ongoing management of the grounding system ensured its continued effectiveness, highlighting the importance of regular maintenance and monitoring. [Conclusion] In conclusion, this study emphasized the indispensable role of effective grounding in university laboratories. Proper grounding not only safeguards personnel and equipment from electrical hazards but also enhances the reliability of scientific research by minimizing data inaccuracies caused by electromagnetic interference. The research advocated for a more refined and systematic approach to grounding management that incorporates professional knowledge and regular inspection routines and proposed that universities should prioritize grounding education and training for laboratory staff to foster a culture of safety and precision. The success of the grounding system at the Analysis & Testing Center serves as a practical example for other institutions seeking to improve their laboratory grounding practices and refine laboratory safety management. [ABSTRACT FROM AUTHOR]

Electroreception is the capacity of living organisms to detect the presence of electricity, usually studied in the aquatic environment. Electroreception in air, however, has received much less attention until relatively recently. Understanding how and why aerial electroreception may work requires a multidisciplinary framework, anchored in both the physics of static electricity and the ecology of sensory biology. In essence, the novel challenge arises from the fact that air is a much less conductive medium than water. Yet, recent research on terrestrial arthropods, including bees, flies, spiders, worms and caterpillars, has unveiled sensitivity to electric fields in different sensory ecological contexts. For each aerial organism considered thus far, filiform hairs and/or the antennae have been proposed to be the specialised sensory structures enabling detection based on both empirical and theoretical evidence. This newfound sensory modality reveals a previously unrecognised source of information, a new informational ecological niche integral to diverse life histories and navigational abilities, which remarkably involves animals, plants and atmospheric electricity (Figure 1). Understanding aerial electroreception in arthropods opens avenues for exploring their behaviour and ecology in diverse environments and sheds light on the evolution of sensory adaptations in terrestrial organisms. Because, as is known today, humans are not sensitive to weak electric fields, challenges arise in our comprehension of the elusive and discrete nature of aerial electric fields, and how they could be detected and used by terrestrial organisms. Daniel Robert introduces aerial electroreception, a sensory modality documented in terrestrial arthropods, such as bees and spiders, that is based on electrostatic charging, and operates in the contexts of plant–pollinator and predator–prey interactions, as well as in dispersal and phoretic behaviours. [ABSTRACT FROM AUTHOR]

Industrialization and human activities have introduced numerous hazards, including exposure to harsh chemicals, radiation, static electricity, and fire risks, particularly in high‐risk sectors such as engineering, rescue operations, military, and aerospace. This study presents a multi‐functional protective textile developed from a conductive fiber composed of polytetrafluoroethylene (PTFE) and carbon nanotubes (CNT), crucial for ensuring personal safety. The conductive fiber demonstrates remarkable strength (17.3 MPa), high porosity (76%), and significant electrical conductivity (185 S m−1), coupled with excellent fineness and flexibility due to its dual‐nanofibrous structure. The resulting textile exhibits exceptional hydrophobicity, chemical resistance, and high electromagnetic interference shielding effectiveness (29 dB in the X‐band), alongside a superior UV protective factor (>3000) and anti‐static properties. Notably, it possesses outstanding electro/photo thermal conversion capabilities, enabling consistent heat generation for personal warmth. Additionally, the textile responds electrically to deformation and temperature changes, facilitating intelligent applications such as motion and temperature monitoring and fire alerts. This work offers a novel strategy for fabricating PTFE‐based composite fibers with porous microstructures and high electrical conductivity, setting a new standard for next‐generation protective clothing with advanced functionalities. [ABSTRACT FROM AUTHOR]

Context: In this work, in order to find new strategy to solve the safe problem of one famous high energy compound 1,3,5-trinitro-1,3,5-triazinane (RDX) under the impact and static electricity environment, cyclo[n]carbons (n = 10, C10; n = 14, C14; n = 18, C18) were employed to construct novel energetic composites (RDX@C10, RDX@C14, RDX@C18) with RDX for the first time. The investigated results showed that C10, C14 and C18 all can form stable composites with RDX through a exothermal process. Three cyclo[n]carbons could not only decrease the impact sensitivity of RDX by decreasing the positive ESP values and transferring the HPV region. But also could reduce the electrostatic sensitivity greatly by decreasing the energy gap, increasing the EHOMO and controlling the active electron-induced process and reaction. Among them, the desensitization effect by C18 and C14 was found to be much better than C10. In addition, three cyclo[n]carbons may be used as new sensors for the detection of RDX, due to the fast recovery time under different lights, and great change in the UV–Vis spectrum. These improvements may provide valuable insights for enhancing the safe performance of high energy compounds with similar structures to RDX, and broaden the application sphere of cyclo[n]carbons. Methods: All of the calculations on the structures were carried out by using the Gaussian 09 software at the M06-2X/6-311G(d,p) level. In addition, further calculations on the properties and interactions were performed by using the Multiwfn software. [ABSTRACT FROM AUTHOR]

Polyester fibers tend to generate static electricity during the weaving and application processes, posing a threat to their production. Enhancing the water absorbency and electrical conductivity of polyester fibers themselves is an effective approach to improving their antistatic properties. In this study, multifunctional chitosan (CS), sodium phytate (SP), and Cu2+ were loaded on polyester fibers through layer-by-layer (LBL) self-assembly. The antistatic and water absorption capability of the modified polyester fibers was investigated by designing different process parameters combined with a surface resistance test and water contact angle tests. The antistatic property test results confirmed the positive effect of CS and Cu2+ on discharging electrostatic charge. Within a definite scope, with the increase in the number of assembly layers, assembly duration, and the concentration of the assembly substances, the wettability of the modified polyester fibers became more favorable and the antistatic effect became more remarkable. [ABSTRACT FROM AUTHOR]

The controllable motion of materials in response to external stimuli has profoundly impacted various applications such as robots, sensors, self-adaptive devices, and targeted therapy. However, remote control of unmodified materials by external signals is still rare. In this work, the controlled motion of marine polysaccharides in tetrachloromethane is found when fingers wearing nitrile gloves touch on or move around the plastic tube, similar to magnet field-driven iron powders. The effects of several key parameters on the magnet-like motion of chitosan are investigated, including solvents, concentrations, molecular weight, and containers. By adjusting these parameters, the formation and degree of magnet-like motion can be significantly tuned. In addition to chitosan, the controllable motion of fucoidan and the chitosan/fucoidan mixture is also detected. Further investigation sheds light on the mechanism of this motion, which is proven to be the force of static electricity. Based on this, chitosan/fucoidan nanoparticles are successfully prepared and manipulated by remote control. Thus, this work offers a facile approach for obtaining controllable motion of marine polysaccharides, opening doors to precise manipulation of nonmagnetic nanomaterials by remote control and holding great potential in nanomedicine, sensors, robotics, etc. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polar skyrmions are topologically stable, swirling polarization textures with particlelike characteristics, which hold promise for next-generation, nanoscale logic and memory. However, the understanding of how to create ordered polar skyrmion lattice structures and how such structures respond to applied electric fields, temperature, and film thickness remains elusive. Here, using phase-field simulations, the evolution of polar topology and the emergence of a phase transition to a hexagonal close-packed skyrmion lattice is explored through the construction of a temperature-electric field phase diagram for ultrathin ferroelectric PbTiO_{3} films. The hexagonal-lattice skyrmion crystal can be stabilized under application of an external, out-of-plane electric field which carefully adjusts the delicate interplay of elastic, electrostatic, and gradient energies. In addition, the lattice constants of the polar skyrmion crystals are found to increase with film thickness, consistent with expectation from Kittel's law. Our studies pave the way for the development of novel ordered condensed matter phases assembled from topological polar textures and related emergent properties in nanoscale ferroelectrics.

Copyright of Packaging & Food Machinery is the property of Packaging & Food Machinery Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Water inrush disasters in karst areas have caused great losses to underground engineering construction, so it is urgent to control water gushing disasters in karst pipelines. In this paper, solution polymerization is used to prepare a grouting and sealing expanded matrix material to control disasters. Noncovalent weak interactions were used to improve the surface properties of the expanded matrix material, the effects of the natural polymer content on the properties of the matrix material were studied, and a modified expanded matrix material with an optimal response rate was prepared. A cross-linked curing agent (CCA) was developed and synthesized, and a new cross-linked expansive grouting and sealing material (WIS grouting material) with various particle sizes was synthesized with noncovalent interactions such as hydrogen bonding, static electricity, van der Waals forces, etc. The results showed that a 4 % solution polymer content (accounting for the particle mass of the expanded matrix) was the optimal dosage, and the optimal ratio of the modified expansion matrix material to the crosslinking curing agent was 1:1. The early compressive strength exceeded 0.2 MPa, and the water absorption rate reached 170 times. There was a power function relationship between the water absorption rate and time, and the rate was controlled by adjusting the particle sizes. The mechanism through which the WIS grouting material underwent expansion and crosslinking was explained at the microscopic level. The gel formed in response to water resisted dispersion in dynamic water and rapidly sealed karst pipe water gushers. This paper proposes a novel approach to utilizing the expansion characteristics of polymer chemical synthetic materials for crosslinking to seal karst pipe water gushers, effectively addressing the issue of poor resistance to dynamic water dispersion in traditional grouting materials used in karst areas. These results provide a scientific basis for the development and application of new materials to control water inrush in karst pipes. [ABSTRACT FROM AUTHOR]

In this article, we use the strategies to engage students in a 5E lesson on static electricity (partially addressing MS-PS2-3). We start the engage phase by using a "magic trick" as a hook to engage students about static electricity. During the explain phase, students get the chance to interact with a variety of static electricity phenomena and write down what they are curious about. Next, we help students make sense of the experiences through teacher questioning in the explore phase. In the elaborate phase, we encourage student speculation and questions by having them generate their own research questions. In the evaluate phase, we use novel scenarios related to what students learned to assess their thinking and maintain curiosity. Throughout all of the 5E, we strive to model curiosity by looking excited, asking speculative questions, and being interested in students' ideas. [ABSTRACT FROM AUTHOR]

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The filtering mechanism of respirators involves static electricity and physical mechanisms, such as inertial impaction, interception, and diffusion. Static electricity is used to reduce pressure resistance, but electrostatic effects and the environmental variables that affect them are not well studied. Therefore, this study evaluated the contribution of static electricity to the filtration efficiency of respirators and the effects of changes in temperature and humidity on static electricity and the resulting filtration efficiency. Eight respirators from four manufacturers—four for workers (1st class respirators) and four for citizens (KF‐94 respirators)—were selected, all of which met legal standards in Korea. The filtration efficiency and pressure drop were evaluated at baseline and after removing static electricity with isopropanol. To study the effects of humidity and temperature on the efficiency of the respirators, the respirators were exposed to 30, 50, and 98% humidity while the temperature was fixed at 25°C and to temperatures of −30, 25, and 70°C while the humidity was fixed at 50%. Static electricity was measured using a surface‐potential meter, and the filtration efficiency was measured using NaCl and paraffin oil. When static electricity was removed from the 1st class and KF‐94 respirators, the filtration efficiency decreased by 21.7% and 19.5%, respectively. Humidity affected the change in static electricity slightly more than temperature, but since not all static electricity was removed, the filtration efficiency was not affected greatly. The changes in static electricity and filtration efficiency due to humidity were significant, but this was because the standard deviation was small. Even under 98% humidity, the filtration efficiency was only 1–2% lower than that at 30% humidity and still met the 94% filtration efficiency criterion for respirators. [ABSTRACT FROM AUTHOR]

This article analyzes and studies the generation, disappearance, and influencing factors of static electricity during the removal of protective film from the module screen, and confirmed the influence trend. To solve the problem of module abnormal display caused by excessive static electricity during film tearing. [ABSTRACT FROM AUTHOR]

Accuracy and transferability are the two highly desirable properties of molecular mechanical force fields. Compared with the extensively used point-charge additive force fields that apply fixed atom-centered point partial charges to model electrostatic interactions, polarizable force fields are thought to have the advantage of modeling the atomic polarization effects. Previous works have demonstrated the accuracy of the recently developed polarizable Gaussian multipole (pGM) models. In this work, we assessed the transferability of the electrostatic parameters of the pGM models with (pGM-perm) and without (pGM-ind) atomic permanent dipoles in terms of reproducing the electrostatic potentials surrounding molecules/oligomers absent from electrostatic parameterizations. Encouragingly, both the pGM-perm and pGM-ind models show significantly improved transferability than the additive model in the tests (1) from water monomer to water oligomer clusters; (2) across different conformations of amino acid dipeptides and tetrapeptides; (3) from amino acid tetrapeptides to longer polypeptides; and (4) from nucleobase monomers to Watson-Crick base pair dimers and tetramers. Furthermore, we demonstrated that the double-conformation fittings using amino acid tetrapeptides in the αR and β conformations can result in good transferability not only across different tetrapeptide conformations but also from tetrapeptides to polypeptides with lengths ranging from 1 to 20 repetitive residues for both the pGM-ind and pGM-perm models. In addition, the observation that the pGM-ind model has significantly better accuracy and transferability than the point-charge additive model, even though they have an identical number of parameters, strongly suggest the importance of intramolecular polarization effects. In summary, this and previous works together show that the pGM models possess both accuracy and transferability, which are expected to serve as foundations for the development of next-generation polarizable force fields for modeling various polarization-sensitive biological systems and processes.

Enzymes host active sites inside protein macromolecules, which have diverse, often incredibly complex, and atom-expensive structures. It is an outstanding question what the role of these expensive scaffolds might be in enzymatic catalysis. Answering this question is essential to both enzymology and the design of artificial enzymes with proficiencies that will match those of the best natural enzymes. Protein rigidifying the active site, contrasted with the dynamics and vibrational motion promoting the reaction, as well as long-range electrostatics (also known as electrostatic preorganization) were all proposed as central contributions of the scaffold to the catalysis. Here, we show that all these effects inevitably produce changes in the quantum mechanical electron density in the active site, which in turn defines the reactivity. The phenomena are therefore fundamentally inseparable. The geometry of the electron density-a scalar field characterized by a number of mathematical features such as critical points-is a rigorous and convenient descriptor of enzymatic catalysis and a reporter on the role of the protein. We show how this geometry can be analyzed, linked to the reaction barriers, and report in particular on intramolecular electric fields in enzymes. We illustrate these tools on the studies of electrostatic preorganization in several representative enzyme classes, both natural and artificial. We highlight the forward-looking aspects of the approach.

Allosteric signaling within multidomain proteins is a driver of communication between spatially distant functional sites. Understanding the mechanism of allosteric coupling in large multidomain proteins is the most promising route to achieving spatial and temporal control of the system. The recent explosion of CRISPR-Cas9 applications in molecular biology and medicine has created a need to understand how the atomic level protein dynamics of Cas9, which are the driving force of its allosteric crosstalk, influence its biophysical characteristics. In this study, we used a synergistic approach of nuclear magnetic resonance (NMR) and computation to pinpoint an allosteric hotspot in the HNH domain of the thermostable GeoCas9. We show that mutation of K597 to alanine disrupts a salt-bridge network, which in turn alters the structure, the timescale of allosteric motions, and the thermostability of the GeoHNH domain. This homologous lysine-to-alanine mutation in the extensively studied mesophilic S. pyogenes Cas9 similarly alters the dynamics of the SpHNH domain. We have previously demonstrated that the alteration of allostery via mutations is a source for the specificity enhancement of SpCas9 (eSpCas9). Hence, this may also be true in GeoCas9.

Graphene is a double-layer flat film composed of multiple atoms. It is mainly based on the hexagonal honeycomb lattice structure composed of carbon atoms in a hybrid structure. The three-dimensional image is like a grid shape on the surface of a football. Double-layer graphene is a two-carbon material composed of two layers of carbon atoms that are periodically and closely packed in a benzene ring structure stacked in a different stacking manner. In this article, this article aims to study the thermodynamic behavior analysis of double-layer graphene. According to a mechanical behavior analysis of football and meshless kp-Rit method, due to the thermodynamic instability of two-dimensional crystals, no matter what whether it is a football shape or a meshless method, the graphene is not a complete plane either freely or deposited on the substrate. On the contrary, there are microscopic wrinkles on the surface. According to observations, this three-dimensional change will cause the generation of static electricity. At the same time, it will also make the connection between different carbon atoms more viscous, and the properties will be more stable. Study the tensile force with stronger fracture strength than steel, through the study of meshless methods and mechanical research models Established, and finally showed that in the experimental results in this article, the angle between the bond and the bond is 120°, and its strength can reach about 150 GPa. [ABSTRACT FROM AUTHOR]

This article investigated prospective biology teachers' skills in compiling science explanations through writing and pictures to support their science explanations. This study involved 15 prospective biology teachers as the research sample. A test was constructed to measure their skills in writing science explanations. In this test, prospective biology teachers were asked to explain the concept of static electricity in living things. To analyze the data, we used the structure of a scientific explanation, which comprises three primary components: premise - accepted knowledge that provides the basis of the explanation, reasoning - logical sequences that follow from the premise, and outcome - the phenomenon to be explained. The reasoning component of the prospective biology teachers' skills in presenting visual representations was poor. This finding supports the necessity of developing the skills of future biology teachers in writing science explanations. [ABSTRACT FROM AUTHOR]

Cell nucleus status decides the activities of corresponding cells, making its rapid and effective staining important for revealing the actual condition of biological environment in life science and related fields. In this study, fast staining of cell nucleus is realized by fluorescent carbon nanodots (CDs). The staining mechanism is due to the positively charged CD surface-induced cell membrane penetration, which facilitates the CD-nucleus binding via electrostatic attraction. The size of cell nucleus is easily measured with fluorescence imaging technique. In addition, the CD-based cell nucleus stain is applied for discriminating the normal and cancer cells by determining the cell-to-nucleus ratio with fluorescence images. [ABSTRACT FROM AUTHOR]

When liquid drops impact on solid surfaces, an air layer forms in between the drop and the surface, acting as a cushion to mitigate the impact. In this work, we focus on delineating the bounce and contact mode regimes of impacting drops on smooth surfaces, specifically discerning whether drops rebound from the air layer or make contact with the solid surfaces, and pinpointing the precise contact modes between the drop and solid surfaces by resolving the gas film evolution and rupture. Our simulation model incorporates gas kinetics and electrostatics effects, both of which have been validated by experiments documented in the literature or theoretical models regarding thin film instabilities. We undertake a comprehensive review and categorization of the contact modes and elucidate how they change under different conditions of impact velocities, ambient pressures, and electric field intensities. We also provide some perspectives on the regime map for the lubricated surfaces, which contains an unresolved issue that the critical Weber number for bouncing-wetting transition is significantly reduced compared to the solid smooth surfaces like mica. These insights have noteworthy practical implications offering guidance for a wide range of scenarios, from normal-pressure environments to low-pressure conditions at high altitudes, encompassing high electric field conditions such as nanogenerators as well as low electric field conditions resembling glass surfaces with static electricity. [ABSTRACT FROM AUTHOR]

The results of studies of the effect of specific surface conductivity γS on the accumulation and dissipation of static electricity (SE) charges on the surface of polymer dielectrics are presented. Samples with a thickness of 1–5 mm with a specific volumetric conductivity of γV60 ≤ 10—12 Ω–1 m–1 were selected for research. It has been found that such dielectrics are characterized by the absence of a steady-state mode after voltage application, since the current flowing through the volume of the dielectric is constantly decreasing. The dependence of γS on the tangential component of constant electric field strength γS = f(Eτ) in the range Eτ = 5 × 102–5 × 105 V/m is studied. It has been found that, for dielectrics with a basic surface conductivity of γS0 < 10–12 Ω–1, a nonlinear dependence of γS = f(Eτ) is observed, and this nonlinearity increases with a decrease in γS0. It has also been found that a more pronounced nonlinearity γS = f(Eτ) is characteristic of hydrophobic dielectrics. Mathematical modeling of the accumulation and dissipation of SE charges is performed without and with taking into account the nonlinear dependence of γS = f(Eτ). It is concluded that, for dielectrics with γV60 ≤ 10–12 Ω–1 m–1, only surface conductivity can be taken into account; moreover, while γS = const for hydrophilic dielectrics, for hydrophobic dielectrics it is necessary to take into account the nonlinear dependence γS = f(Eτ). [ABSTRACT FROM AUTHOR]

Contact electrification, or contact charging, refers to the process of static charge accumulation after rubbing, or even simple touching, of two materials. Despite its relevance in static electricity, various natural phenomena, and numerous technologies, contact charging remains poorly understood. For insulating materials, even the species of charge carrier may be unknown, and the direction of charge-transfer lacks firm molecular-level explanation. Here, we use all-atom molecular dynamics simulations to investigate whether thermodynamics can explain contact charging between insulating polymers. Based on prior work suggesting that water-ions, such as hydronium and hydroxide ions, are potential charge carriers, we predict preferred directions of charge-transfer between polymer surfaces according to the free energy of water-ions within water droplets on such surfaces. Broad agreement between our predictions and experimental triboelectric series indicate that thermodynamically driven ion-transfer likely influences contact charging of polymers. Furthermore, simulation analyses reveal how specific interactions of water and water-ions proximate to the polymer-water interface explain observed trends. This study establishes relevance of thermodynamic driving forces in contact charging of insulators with new evidence informed by molecular-level interactions. These insights have direct implications for future mechanistic studies and applications of contact charging involving polymeric materials. Contact electrification is a widely observed phenomenon in nature and in materials. Here, the authors use molecular dynamics simulations to show the importance of thermodynamic driving forces in contact electrification in insulating materials. [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG) is an important and popular phase change material (PCM), but is not a good antistatic material, which would cause the accumulation of static electricity and electrostatic discharge when used for the thermal energy storage and thermal management of electrical devices. Herein, we prepared a PEG‐based solid–solid PCM (SSPCM) with good antistatic property by introducing an ionic liquid onto the macromolecular chains. This SSPCM is in solid state even at 90°C, avoiding the leakage issue of pure PEG. Its latent heat values in the melting and solidifying processes are 56.2 and 30.6 J g−1, respectively. Additionally, this SSPCM has good thermal stability and thermal reliability for thermal storage and thermal management according to thermogravimetric and thermal cycling tests. The volume‐ and surface resistivity of the SSPCM at ambient temperature are 108.87 Ω m and 108.92 Ω, respectively, showing good antistatic performance. [ABSTRACT FROM AUTHOR]

Instrumental resolution of Fourier transform-charge detection mass spectrometry instruments with electrostatic ion trap detection of individual ions depends on the precision with which ion energy is determined. Energy can be selected using ion optic filters or from harmonic amplitude ratios (HARs) that provide Fellgett's advantage and eliminate the necessity of ion transmission loss to improve resolution. Unlike the ion energy-filtering method, the resolution of the HAR method increases with charge (improved S/N) and thus with mass. An analysis of the HAR method with current instrumentation indicates that higher resolution can be obtained with the HAR method than the best resolution demonstrated for instruments with energy-selective optics for ions in the low MDa range and above. However, this gain is typically unrealized because the resolution obtainable with molecular systems in this mass range is limited by sample heterogeneity. This phenomenon is illustrated with both tobacco mosaic virus (0.6-2.7 MDa) and AAV9 (3.7-4.7 MDa) samples where mass spectral resolution is limited by the sample, including salt adducts, and not by instrument resolution. Nevertheless, the ratio of full to empty AAV9 capsids and the included genome mass can be accurately obtained in a few minutes from 1× PBS buffer solution and an elution buffer containing 300+ mM nonvolatile content despite extensive adduction and lower resolution. Empty and full capsids adduct similarly indicating that salts encrust the complexes during late stages of droplet evaporation and that mass shifts can be calibrated in order to obtain accurate analyte masses even from highly salty solutions.

Molecular modeling at the atomic level has been applied in a wide range of biological systems. The widely adopted additive force fields typically use fixed atom-centered partial charges to model electrostatic interactions. However, the additive force fields cannot accurately model polarization effects, leading to unrealistic simulations in polarization-sensitive processes. Numerous efforts have been invested in developing induced dipole-based polarizable force fields. Whether additive atomic charge models or polarizable induced dipole models are used, proper parameterization of the electrostatic term plays a key role in the force field developments. In this work, we present a Python program called PyRESP for performing atomic multipole parameterizations by reproducing ab initio electrostatic potential (ESP) around molecules. PyRESP provides parameterization schemes for several electrostatic models, including the RESP model with atomic charges for the additive force fields and the RESP-ind and RESP-perm models with additional induced and permanent dipole moments for the polarizable force fields. PyRESP is a flexible and user-friendly program that can accommodate various needs during force field parameterizations for molecular modeling of any organic molecules.

It has been observed that, before some strong earthquakes occur, the space static electricity near the ground is abnormal, which might be caused by a large amount of radioactive gas released from the Earth's crust. In this paper, the information diffusion technology for optimally processing small samples is used to analyze 30 cases, and the relationship between magnitude and parameters such as abnormality of space static electricity is constructed. Each case is composed of four observation values: abnormality e, epicenter distance d, impending time t and magnitude m. Using the causal relationship constructed in this paper, the magnitude m of an impending earthquake could be approximately inferred from abnormality e. According to the progress of locking the epicenter and the passage of time, the predicted magnitude could be adjusted in a timely manner. The research results provided in this paper do not eliminate the uncertainty of earthquake occurrence, so that the study is a work of analyzing seismic dynamic risk. Integrating the monitoring information from seismic stations and the physical field information in the air will promote impending earthquake prediction, which is a worldwide scientific challenge.

GeomBD3 is a robust Brownian dynamics simulation package designed to easily handle natural or engineered systems in diverse environments and arrangements. The software package described herein allows users to design, execute, and analyze BD simulations. The simulations use all-atom, rigid molecular models that diffuse according to overdamped Langevin dynamics and interact through electrostatic, Lennard-Jones, and ligand desolvation potentials. The program automatically calculates molecular association rates, surface residence times, and association statistics for any number of user-defined association criteria. Users can also extract molecular association pathways, diffusion coefficients, intermolecular interaction energies, intermolecular contact probability maps, and more using the provided supplementary analysis scripts. We detail the use of the package from start to finish and apply it to a protein-ligand system and a large nucleic acid biosensor. GeomBD3 provides a versatile tool for researchers from various disciplines that can aid in rational design of engineered systems or play an explanatory role as a complement to experiments. GeomBD version 3 is available on our website at http://chemcha-gpu0.ucr.edu/geombd3/ and KBbox at https://kbbox.h-its.org/toolbox/methods/molecular-simulation/geombd/.

GPIHBP1, an endothelial cell (EC) protein, captures lipoprotein lipase (LPL) within the interstitial spaces (where it is secreted by myocytes and adipocytes) and transports it across ECs to its site of action in the capillary lumen. GPIHBP1's 3-fingered LU domain is required for LPL binding, but the function of its acidic domain (AD) has remained unclear. We created mutant mice lacking the AD and found severe hypertriglyceridemia. As expected, the mutant GPIHBP1 retained the capacity to bind LPL. Unexpectedly, however, most of the GPIHBP1 and LPL in the mutant mice was located on the abluminal surface of ECs (explaining the hypertriglyceridemia). The GPIHBP1-bound LPL was trapped on the abluminal surface of ECs by electrostatic interactions between the large basic patch on the surface of LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the surface of ECs. GPIHBP1 trafficking across ECs in the mutant mice was normalized by disrupting LPL-HSPG electrostatic interactions with either heparin or an AD peptide. Thus, GPIHBP1's AD plays a crucial function in plasma triglyceride metabolism; it sheathes LPL's basic patch on the abluminal surface of ECs, thereby preventing LPL-HSPG interactions and freeing GPIHBP1-LPL complexes to move across ECs to the capillary lumen.

We report the measurement and analysis of sulfonium-π, thioether-π, and ammonium-π interactions in a β-hairpin peptide model system, coupled with computational investigation and PDB analysis. These studies indicated that the sulfonium-π interaction is the strongest and that polarizability contributes to the stronger interaction with sulfonium relative to ammonium. Computational studies demonstrate that differences in solvation of the trimethylsulfonium versus the trimethylammonium group also contribute to the stronger sulfonium-π interaction. In comparing sulfonium-π versus sulfur-π interactions in proteins, analysis of SAM- and SAH-bound enzymes in the PDB suggests that aromatic residues are enriched in close proximity to the sulfur of both SAM and SAH, but the populations of aromatic interactions of the two cofactors are not significantly different, with the exception of the Me-π interactions in SAM, which are the most prevalent interaction in SAM but are not possible for SAH. This suggests that the weaker interaction energies due to loss of the cation-π interaction in going from SAM to SAH may contribute to turnover of the cofactor.

Control over supramolecular recognition between proteins and nanoparticles (NPs) is of fundamental importance in therapeutic applications and sensor development. Most NP-protein binding approaches use 'tags' such as biotin or His-tags to provide high affinity; protein surface recognition provides a versatile alternative strategy. Generating high affinity NP-protein interactions is challenging however, due to dielectric screening at physiological ionic strengths. We report here the co-engineering of nanoparticles and protein to provide high affinity binding. In this strategy, 'supercharged' proteins provide enhanced interfacial electrostatic interactions with complementarily charged nanoparticles, generating high affinity complexes. Significantly, the co-engineered protein-nanoparticle assemblies feature high binding affinity even at physiologically relevant ionic strength conditions. Computational studies identify both hydrophobic and electrostatic interactions as drivers for these high affinity NP-protein complexes.

Development of inhibitors for histone methyllysine reader proteins is an active area of research due to the importance of reader protein-methyllysine interactions in transcriptional regulation and disease. Optimized peptide-based chemical probes targeting methyllysine readers favor larger alkyllysine residues in place of methyllysine. However, the mechanism by which these larger substituents drive tighter binding is not well understood. This study describes the development of a two-pronged approach combining genetic code expansion (GCE) and structure-activity relationships (SAR) through systematic variation of both the aromatic binding pocket in the protein and the alkyllysine residues in the peptide to probe inhibitor recognition in the CBX5 chromodomain. We demonstrate a novel change in driving force for larger alkyllysines, which weaken cation-π interactions but increases dispersion forces, resulting in tighter binding. This GCE-SAR approach establishes discrete energetic contributions to binding from both ligand and protein, providing a powerful tool to gain mechanistic understanding of SAR trends.

Utilizing electric fields to catalyze chemical reactions is not a new idea, but in enzymology it undergoes a renaissance, inspired by Warhsel's concept of electrostatic preorganization. According to this concept, the source of the immense catalytic efficiency of enzymes is the intramolecular electric field that permanently favors the reaction transition state over the reactants. Within enzyme design, computational efforts have fallen short in designing enzymes with natural-like efficacy. The outcome could improve if long-range electrostatics (often omitted in current protocols) would be optimized. Here, we highlight the major developments in methods for analyzing and designing electric fields generated by the protein scaffolds, in order to both better understand how natural enzymes function, and aid artificial enzyme design.

Transcription factors must scan genomic DNA, recognize the cognate sequence of their control element(s), and bind tightly to them. The DNA recognition process is primarily carried out by their DNA binding domains (DBD), which interact with the cognate site with high affinity and more weakly with any other DNA sequence. DBDs are generally thought to bind to their cognate DNA without changing conformation (lock-and-key). Here, we used nuclear magnetic resonance and circular dichroism to investigate the interplay between DNA recognition and DBD conformation in the engrailed homeodomain (enHD), as a model case for the homeodomain family of eukaryotic DBDs. We found that the conformational ensemble of enHD is rather flexible and becomes gradually more disordered as ionic strength decreases following a Debye-Hückel's dependence. Our analysis indicates that enHD's response to ionic strength is mediated by a built-in electrostatic spring-loaded latch that operates as a conformational transducer. We also found that, at moderate ionic strengths, enHD changes conformation upon binding to cognate DNA. This change is of larger amplitude and somewhat orthogonal to the response to ionic strength. As a consequence, very high ionic strengths (e.g., 700 mM) block the electrostatic-spring-loaded latch and binding to cognate DNA becomes lock-and-key. However, the interplay between enHD conformation and cognate DNA binding is robust across a range of ionic strengths (i.e., 45 to 300 mM) that covers the physiologically-relevant conditions. Therefore, our results demonstrate the presence of a mechanism for the conformational control of cognate DNA recognition on a eukaryotic DBD. This mechanism can function as a signal transducer that locks the DBD in place upon encountering the cognate site during active DNA scanning. The electrostatic-spring-loaded latch of enHD can also enable the fine control of DNA recognition in response to transient changes in local ionic strength induced by variate physiological processes.