As the potential adverse health and environmental effects of nanoscale pollutants have garnered significant attention, the demand for monitoring and capturing ultrafine particulate matter has been growing. With the rise in ultrafine dust emissions, this issue has become increasingly important. However, submicron particles require advanced strategies to be captured because of their limited inertial effect. For example, electrostatic air filters have been investigated for their improved performance in the fine particle regime. On the other hand, Raman spectroscopy was proposed as a promising analytical strategy for aerosol particles because it can be used to conveniently detect analytes in a label-free manner. Thus, the synergistic integration of these strategies can open new applications for addressing environment-related challenges. This study presents a multifunctional approach for achieving both air filtration and surface-enhanced Raman scattering (SERS) for analyte identification. We propose a nanoporous membrane composed of a thin gold layer, copper, and copper oxide to provide the desired functions. The structures are produced by performing scalable electrodeposition and subsequent electron-beam evaporation, attaining an excellent filtration efficiency of 95.9% with an applied voltage of 5 kV for 300 nm KCl particles and a pressure drop of 121 Pa. Raman intensity measurements confirm that the nanodendritic surface of the membrane intensifies the Raman signals and allows for the detection of 10 μL of nanoplastic particle dispersion with a concentration of 50 μg/mL. Rhodamine 6G aerosol stream with an approximate particle deposition rate of 0.040 × 106 mm-2·min-1 is also identified in a minimum detectable time of 50 s. The membrane is shown to be recyclable owing to its structural robustness in organic solvents. In addition, the fatigue resistance of the structure is evaluated through 22,000 iterative loading cycles at a pressure of 177 kPa. No performance degradation is observed after the fatigue loading.

In this paper, we present a compressive study on the design and development of a MEMS ring resonator and its dynamic behavior under electrostatic force when supported by twin circular curve beams. Finite element analysis (FEA)-based modeling techniques are used to simulate and refine the resonator geometry and transduction. In proper FEA or analytical modeling, the explicit description and accurate values of the effective mass and stiffness of the resonator structure are needed. Therefore, here we outlined an analytical model approach to calculate those values using the first principles of kinetic and potential energy analyses. The natural frequencies of the structure were then calculated using those parameters and compared with those that were simulated using the FEA tool ANSYS. Dynamic analysis was performed to calculate the pull-in voltage, shift of resonance frequency, and harmonic analyses of the ring to understand how the ring resonator is affected by the applied voltage. Additional analysis was performed for different orientations of silicon and assessing the frequency response and frequency shifts. The prototype was fabricated using the standard silicon-on-insulator (SOI)-based MEMS fabrication process and the experimental results for resonances showed good agreement with the developed model approach. The model approach presented in this paper can be used to provide valuable insights for the optimization of MEMS resonators for various operating conditions.

Controllable droplet manipulation has diverse applications; however, limited methods exist for externally manipulating droplets in confined spaces. Herein, we propose a portable triboelectric electrostatic tweezer (TET) by integrating electrostatic forces with a superhydrophobic surface that can even manipulate droplets in an enclosed space. Electrostatic induction causes the droplet to be subjected to an electrostatic force in an electrostatic field so that the droplet can be moved freely with the TET on a superhydrophobic platform. Characterized by its high precision, flexibility, and robust binding strength, TET can manipulate droplets under various conditions and achieve a wide range of representative fluid applications such as droplet microreactors, precise self-cleaning, cargo transportation, the targeted delivery of chemicals, liquid sorting, soft droplet robotics, and cell labeling. Specifically, TET demonstrated the ability to manipulate internal droplets from the outside of a closed system, such as performing cell labeling experiments within a sealed Petri dish without opening the culture system.

Poor skin adhesion and mechanical properties are common problems of pressure-sensitive adhesive (PSA) in transdermal drug delivery system (TDDS). Its poor water compatibility also causes the patch to fall off after sweating or soaking in the application site. To solve this problem, poly (2-Ethylhexyl acrylate-co-N-Vinyl-2-pyrrolidone-co-N-(2-Hydroxyethyl)acrylamide) (PENH), a cross-linked pyrrolidone polyacrylate PSA, was designed to improve the adhesion and water resistance of PSA through electrostatic force and hydrogen bonding system. The structure of PENH was characterized by 1H NMR, FTIR, DSC, and other methods. The mechanism was studied by FTIR, rheological test, and molecular simulation. The results showed that the PENH patch could adhere to human skin for more than 10 days without cold flow, and it could still adhere after sweating or water contact. In contrast, the commercial PSA Duro-Tak® 87-4098 and Duro-Tak® 87-2852 fell off completely on the 3rd and 6th day, respectively, and Duro-Tak® 87-2510 showed a significant dark ring on the second day. Mechanism studies have shown that the hydrogen bond formed by 2-ethylhexyl acrylate (2-EHA), N-vinyl-2-pyrrolidinone (NVP), and N-(2-Hydroxyethyl)acrylamide (HEAA) enhances cohesion, the interaction with skin improves skin adhesion, and the electrostatic interaction with water or drug molecules enhances the ability of water absorption and drug loading. Due to the synergistic effect of hydrogen bonds and electrostatic force, PENH can maintain high cohesion after drug loading or water absorption. PENH provides a choice for the development of water-compatible patches with long-lasting adhesion. STATEMENT OF SIGNIFICANCE: Based on the synergistic effect of hydrogen bonding and electrostatic force, a hydrogen-bonded, cross-linked pyrrolidone acrylate pressure-sensitive adhesive for transdermal drug delivery was designed and synthesized, which has high adhesion and cohesive strength and is non-irritating to the skin. The patch can be applied on the skin surface continuously for more than 10 days without the phenomenon of \"dark ring\", and the patch can remain adherent after the patient sweats or bathes. This provides a good strategy for choosing a matrix for patches that require prolonged administration.

In this study, the various amounts of poly-N-vinylpyrrolidone (PVPr) were added to the cement paste, and some parameters - flowing, initial and final setting points, water absorption, compressive strength, and flexural strength were determined. The concrete containing 0.8% PVPr exhibited high water absorption, specifically, at 14 and 28 days, increased from 15.65% to 20.71% and from 16.74% to 21.67%, respectively. The final setting time increased from 238 min to 261 min. It was determined that the compressive strength of the cement mortar increased from 54.8 MPa to 58.5 MPa when the PVPr content was 0.8-1.0%. The flexural strength also improved due to the presence of PVPr, increasing from 11.58 MPa to 14.27 MPa. According to the FTIR characterization, the PVPr macromolecule interacts with Ca2+ and Al3+ ions. TGA analysis reveals that the chemical interaction of PVPr with calcium and aluminum ions limits its mass loss up to 4-5% until 400 °C.

While there are many droplet manipulation techniques, all of them suffer from at least one of the following drawbacks - complex fabrication or complex equipment or liquid loss. In this work, a simple and portable technique is demonstrated that enables on-demand, contact-less and loss-less manipulation of liquid droplets through a combination of contact electrification and slipperiness. In conjunction with numerical simulations, a quantitative analysis is presented to explain the onset of droplet motion. Utilizing the contact electrification technique, contact-less and loss-less manipulation of polar and non-polar liquid droplets on different surface chemistries and geometries is demonstrated. It is envisioned that the technique can pave the way to simple, inexpensive, and portable lab on a chip and point of care devices.

In urban areas, a major source of harmful particulate matter is generated by vehicles. In particular, bus stops, where people often stay for public transportation, generate high concentrations of particulate matter compared to the general atmosphere. In this study, a non-powered type brush filter that generates electrostatic force without using a separate power source was developed to manage the concentration of particulate matter exposed at bus stops, and the removal performance of particulate matter was evaluated. The dust collection performance of the non-motorized brush filter varied by material, with particle removal efficiencies of 82.1 ± 3.4, 76.1 ± 4.7, and 73.7 ± 4.5% for horse hair, nylon, and stainless steel, respectively. In conditions without the fan running to see the effect of airflow, the particle removal efficiency was relatively low at 58.2 ± 8.4, 53.6 ± 9.2, and 58.0 ± 7.3%. Then, to check the dust collection performance according to the density, the number of brushes was increased to densify the density, and the horse hair, nylon, and stainless steel brush filters showed a maximum dust collection performance of 89.6 ± 2.2, 88.3 ± 3.2, and 82.1 ± 3.8%, respectively. To determine the replacement cycle of the non-powered brush filter, the particulate removal performance was initially 88.0 ± 3.2% when five horse hair brushes were used. Over time, particulate matter tended to gradually decrease, but after a period of time, particulate matter tended to increase again. The purpose of this study is to evaluate the particulate matter removal performance using a brush filter that generates electrostatic force without a separate power source. This study\'s brush filter is expected to solve the maintenance problems caused by the purchase and frequent replacement of expensive HEPA filters that occur with existing abatement devices, and the ozone problems caused by abatement devices that use high voltages.

It has been recently demonstrated that free DNA tracers have the potential in tracing water flow and contaminant transport through the vadose zone. However, whether the free DNA tracer can be used in flood irrigation area to track water flow and solute/contaminant transport is still unclear. To reveal the infiltration process and retention mechanisms of surface applied free DNA tracer through soil under flood irrigation, we tested the fate and transport behavior of surface applied free DNA tracers through packed saturated sandy soil columns with a 10 cm water head mimicking flood irrigation. From the experimental breakthrough curves and by fitting a two-site kinetic sorption model (R2 = 0.83-0.91 and NSE = 0.79-0.89), adsorption/desorption rates could be obtained and tracer retention profiles could be simulated. Together these results revealed that 1) the adsorption of free DNA was dominantly to clay particles in the soil, which took up 1.96 % by volume, but took up >97.5 % by surface area and densely cover the surface of sand particles; and 2) at a pore water pH of 8.0, excluding the 4.9 % passing through and 3.1 % degradation amount, the main retention mechanisms in the experimental soil were ligand exchange (42.0 %), Van der Waals interactions (mainly hydrogen bonds), electrostatic forces and straining (together 44.7 %), and cation bridge (5.3 %). To our knowledge, this study is the first to quantify the contribution of each of the main retention mechanisms of free synthetic DNA tracers passing through soil. Our findings could facilitate the application of free DNA tracer to trace vadose zone water flow and solute/contaminant transport under flood irrigation and other infiltration conditions.

Plica neuropathica (PN), also known as plica polonica, trichoma, matting, felting, or bird\'s nest hair, is a common but rarely reported hair disorder. It is characterized by the abrupt onset of irreversible hair entanglement, forming a densely matted hair mass. PN has been associated with the use of ionic or herbal shampoos, vigorous hair care practice, self-neglect, systemic infection, parasitic infestation, immunosuppressive drugs, and psychiatric conditions. However, literature supporting the coexistence of PN in psychiatric disorders is scarce. PN may be one of the presenting symptoms observed by physicians. In some cases of psychiatric illness, patients consult more readily with non-mental health professionals than psychologists or psychiatrists. To highlight this issue, we herein report a case of PN in a 32-year-old woman with a 1-month history of being unable to detangle her hair. The patient initially visited the dermatology department and was subsequently diagnosed with schizophrenia following psychiatric consultation. After establishing the fundamental diagnosis apparently underlying the PN, psychiatric treatment with antipsychotic medication and dermatological treatment of the hair condition were instituted. There was an improvement in both at the four-week follow-up. This case history highlights a rare presentation of schizophrenia.

Carbon nanospikes (CNSs) are a new nanomaterial that has enhanced surface roughness and surface oxide concentration, increasing the sensitivity for dopamine detection. However, CNS-modified electrodes (CNSMEs) have not been characterized for other neurochemicals, particularly those with higher oxidation potentials. The purpose of this study was to evaluate CNSMEs for the detection of adenosine, hydrogen peroxide (H2O2), and histamine. The sensitivity increased with CNSs, and signals at CNSMEs were about 3.3 times higher than CFMEs. Normalizing for surface area differences using background currents, CNSMEs show an increased signal of 4.8 times for adenosine, 1.5 times for H2O2, and 2 times for histamine. CNSMEs promoted the formation of secondary products for adenosine and histamine, which enables differentiation from other analytes with similar oxidation potentials. CNSs also selectively enhance the sensitivity for adenosine and histamine compared to H2O2. A scan rate test reveals that adenosine is more adsorption-controlled at CNS electrodes than CFMEs. CNSMEs are antifouling for histamine, with less fouling because the polymers formed after histamine electrooxidation do not adsorb due to an elevated number of edge planes. CNSMEs were useful for detecting each analyte applied in brain slices. Because of the hydrophilic surface compared to CFMEs, CNSMEs also have reduced biofouling when used in tissue. Therefore, CNSMEs are useful for tissue measurements of adenosine, hydrogen peroxide, and histamine with high selectivity and low fouling.