The Role of Surface Treatment and Coupling Agents for Adhesion between Stainless Steel (SUS) and Polyamide (PA) of Heterojunction Bilayer Composites.

The growing demand for lightweight and durable materials in industries, such as the automotive, aerospace, and electronics industries, has spurred the development of heterojunction bilayer composites, combining the structural integrity of metals with the versatility of polymers. This study addresses the critical interface between stainless steel (SUS) and polyamide 66 (PA66), focusing on the pivotal role of surface treatments and various silane coupling agents in enhancing the adhesion strength of heterojunction SUS/PA66 bilayer composites. Through systematic surface modifications-highlighted by scanning electron microscopy, atomic force microscopy, and contact angle analyses-the study assessed the impact of increasing the surface area, roughness, and energy of SUS. X-ray photoelectron spectroscopy evaluations confirmed the strategic selection of specific silane coupling agents. Although some coupling agents barely influenced the mechanics, notably, aminopropyl triethoxysilane (A1S) and 3-glycidyl oxypropyl trimethoxysilane (ES) significantly enhanced the mechanical properties of the heterojunction bilayer composites, evidenced by the improved lap shear strength, elongation at break, and toughness. These advancements were attributed to the interfacial interactions at the metal-polymer interface. This research underscored the significance of targeted surface treatment and the judicious selection of coupling agents in optimizing the interfacial adhesion and overall performance of metal-polymer composites, offering valuable insights for the fabrication of materials where reduced weight and enhanced durability are paramount.

Rapid detection and identification of microplastics from nonchemically treated soil with CARS microspectroscopy.

In conventional microplastic (MP) analysis, acid or alkaline digestion is a necessary pretreatment step to remove residual organic matter from environmental samples. However, such a digestion process is not only cumbersome and time-consuming, but also possibly cause severe chemical damage to the MP itself, often making accurate MP characterization difficult. This study demonstrates that broadband coherent anti-Stokes Raman scattering (CARS) microspectroscopy is useful for rapidly detecting and identifying MPs in natural soil without any digestion process. A feasibility test is performed with soil samples, which are known to require the most complicated chemical pretreatment for MP analysis, deliberately mixed with various MP particles. The C-H bond-specific CARS imaging and spectral analysis allow rapid MP particle search and chemical identification even in the presence of other residual particles and strongly fluorescent substances from the soil. It is anticipated that this nondestructive, chemical pretreatment-free CARS approach will be a beneficial tool for studying the ecological impacts of MPs absorbed by terrestrial life, such as plants and soil organisms, as well as for complementary analysis of MPs subject to chemical degradation by digestion in investigating the environmental contamination of the MPs.

Novel Single-Particle Analytical Technique for Inhalable Airborne Microplastic Particles by the Combined Use of Fluorescence Microscopy, Raman Microspectrometry, and SEM/EDX.

This study presents a novel and efficient method for analyzing inhalable airborne microplastics (AMPs) in ambient PM10 aerosols. Although many studies have been conducted on MPs in a variety of environments, the physicochemical characteristics of AMPs of inhalable size (<10 µm) in ambient PM10 are poorly understood because of the lack of suitable analytical methods. The method employed in this study combines fluorescence microscopy, Raman microspectrometry (RMS), and scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDX) for an efficient and reliable investigation of inhalable AMPs, which constitute a small portion of ambient PM10 aerosol particles. Fluorescence microscopy and staining are used to select particles with high MP potential from ambient urban PM10 aerosols. The combination of RMS and SEM/EDX then allows for a detailed characterization of these particles on a single-particle basis. The results of the study show that ∼0.008% of the particles collected using a PM10 sampler had high MP potential, corresponding to ∼800 particles/m3. Among the stained particles of <10 µm, 27% were determined to be plastic, while the remaining 73% were found to be from tire/road wear. The number of inhalable AMPs was estimated to be 192 (±127) particles/m3. This study provides an important insight into the characteristics of inhalable AMPs in ambient PM10 aerosols that are particularly critical in respect of human health and climate change. The authors highlight that the use of a single fluorescence staining method can overestimate the number of inhalable AMPs in ambient air by including tire/road wear particles. To the best of their knowledge, this is the first study to demonstrate the morphological and spectroscopic characteristics of the same individual inhalable AMPs.

Anti-Aging and Lightening Effects of Au-Decorated Zeolite-Based Biocompatible Nanocomposites in Epidermal Delivery Systems.

The main challenges in developing zeolites as cosmetic drug delivery systems are their cytotoxicities and the formation of drug-loading pore structures. In this study, Au-decorated zeolite nanocomposites were synthesized as an epidermal delivery system. Thus, 50 nm-sized Au nanoparticles were successfully deposited on zeolite 13X (super cage (α) and sodalite (ß) cage structures) using the Turkevich method. Various cosmetic drugs, such as niacinamide, sulforaphane, and adenosine, were loaded under in vitro and in vivo observations. The Au-decorated zeolite nanocomposites exhibited effective cosmetic drug-loading efficiencies of 3.5 to 22.5 wt% under various conditions. For in vitro cytotoxic observations, B16F10 cells were treated with various cosmetic drugs. Niacinamide, sulforaphane, and adenosine-loaded Au-decorated zeolite nanocomposites exhibited clear cell viability of over 80%. Wrinkle improvement and a reduction in melanin content on the skin surface were observed in vivo. The adenosine delivery system exhibited an enhanced wrinkle improvement of 203% compared to 0.04 wt% of the pure adenosine system. The niacinamide- and sulforaphane-loaded Au-decorated zeolite nanocomposites decreased the skin surface melanin content by 123% and 222%, respectively, compared to 2 and 0.01 wt% of pure niacinamide and sulforaphane systems, respectively. As a result, Au-decorated zeolite nanocomposites show great potential as cosmetic drug epidermal delivery systems for both anti-aging and lightening effects.

Spike frequency adaptation facilitates the encoding of input gradient in insect olfactory projection neurons.

The olfactory system in insects has evolved to process the dynamic changes in the concentration of food odors or sex pheromones to localize the nutrients or conspecific mating partners. Experimental studies have suggested that projection neurons (PNs) in insects encode not only the stimulus intensity but also its rate-of-change (input gradient). In this study, we aim to develop a simple computational model for a PN to understand the mechanism underlying the coding of the rate-of-change information. We show that the spike frequency adaptation is a potential key mechanism for reproducing the phasic response pattern of the PN in Drosophila. We also demonstrate that this adaptation mechanism enables the PN to encode the rate-of-change of the input firing rate. Finally, our model predicts that the PN exhibits the intensity-invariant response for the pulse and ramp odor stimulus. These results suggest that the developed model is useful for investigating the coding principle underlying olfactory information processing in insects.

Novel Single-Particle Analytical Technique for Submicron Atmospheric Aerosols: Combined Use of Dark-Field Scattering and Surface-Enhanced Raman Spectroscopy.

Raman microspectrometry (RMS) is a useful single particle analysis method that can provide information on the mixing states, molecular species, and chemical functional groups of individual aerosol particles, which are difficult to determine by bulk analysis techniques. On the other hand, drawbacks, such as low Raman cross-section, spatial resolution (∼1 µm), and optical diffraction limit, make the analysis of atmospheric particles in the submicron size range difficult using conventional RMS. This study developed a new strategy to detect individual submicron-size atmospheric particles by combining dark-field (DF) microscopy and surface-enhanced Raman spectroscopy (SERS). The DF technique overcomes optical spatial diffraction limit by contrast enhancement, allowing the visualization of submicron particles. SERS facilitates spectroscopic characterization (obtaining information on molecular fingerprints and mixing states) of trace amounts of analyte by increasing the Raman scattering cross-section at the hot spot. SERS-active silver substrates sputter-coated on a Si wafer efficiently provided a clear background in the dark-field image and uniform hot spots over a large area, which were suitable for single-particle analysis. Various functional groups in individual particles and their heterogeneous mixing states were investigated, demonstrating the potential of this method to provide improved information on submicron atmospheric particles of femtogram-level masses. DF-SERS may elucidate the detailed physicochemical characteristics of individual submicron particles, providing new information on the formation mechanisms and fates of atmospheric particles.

Inhibitory functions of maslinic acid, a natural triterpene, on HMGB1-mediated septic responses.

BACKGROUND: Maslinic acid (MA), a natural triterpenoid from Olea europaea, prevents oxidative stress and pro-inflammatory cytokine generation. High mobility group box 1 (HMGB1) has been recognized as a late mediator of sepsis, and the inhibition of the release of HMGB1 and the recovery of vascular barrier integrity have emerged as attractive therapeutic strategies for the management of sepsis. METHODS: We tested the hypothesis that MA induces sirtuin 1 and heme oxygenase-1, which inhibit the release of HMGB1 in lipopolysaccharide (LPS)-stimulated cells, thus inhibiting HMGB1-induced hyperpermeability and increasing the survival of septic mice. MA was administered after LPS or HMGB1 challenge, and the antiseptic activity of MA was determined based on permeability, the activation of pro-inflammatory proteins, and the production of markers for tissue injury in HMGB1-activated human umbilical vein endothelial cells (HUVECs) and a cecal ligation and puncture (CLP)-induced sepsis mouse model. RESULTS: MA significantly reduced the release of HMGB1 in LPS-activated HUVECs and attenuated the CLP-induced release of HMGB1. Additionally, MA alleviated HMGB1-mediated vascular disruption and inhibited hyperpermeability in mice, and in vivo analysis revealed that MA reduced sepsis-related mortality and tissue injury. CONCLUSION: Taken together, the present results suggest that MA reduced HMGB1 release and septic mortality and thus may be useful in the treatment of sepsis.

Pregabalin and Dexmedetomidine Combined for Pain After Total Knee Arthroplasty or Total Hip Arthroplasty Performed Under Spinal Anesthesia.

Pregabalin and dexmedetomidine have been introduced to manage postoperative pain. This study evaluated the effect of the 2 drugs combined on pain in patients undergoing total knee or hip arthroplasty. A total of 124 patients undergoing total knee or hip arthroplasty under spinal anesthesia were randomly assigned to either group C (n=31, placebo), group P (n=33, pregabalin), group PD (n=29, pregabalin and dexmedetomidine), or group D (n=31, dexmedetomidine). One hour before spinal anesthesia, patients received 150 mg of pregabalin or placebo orally, and a bolus dose of 0.5 µg/ kg of intravenous dexmedetomidine was given over 10 minutes before induction of spinal anesthesia. This was followed by a continuous infusion of 0.5 µg/kg/h or the same calculated volume of normal saline until completion of the surgery. Clinically relevant pain for 24 hours postoperatively, including time to first analgesic request, visual analog scale score, ketorolac dose, and volume of patient-controlled analgesia consumed, was recorded. Group C had significantly longer time to first analgesic request, higher visual analog scale scores at rest and on movement, higher ketorolac dose, and higher volume of patient-controlled analgesia for the first 24 hours postoperatively compared with the other groups. Although group PD and group D had less clinically relevant pain than group P, group PD and group D were not significantly different. Dexmedetomidine was more effective than pregabalin for clinically relevant pain. Pregabalin and dexmedetomidine combined had no synergic effect compared with dexmedetomidine alone. [Orthopedics. 2018; 41(6):365-370.].

The effects of a combination of intravenous dexamethasone and ketamine on postoperative mood in patients undergoing laparoscopically assisted-gynecologic surgery.

BACKGROUND: It has been known that anesthetic adjuvants such as dexamethasone or ketamine might change mood. This study aimed to investigate the effects of a single dose of each drug individually along with their combined usage on postoperative mood changes in patients undergoing gynecologic surgery. METHODS: Two hundred ninety-seven patients randomly allocated were divided into three groups. Group K (n = 99) received a single dose of ketamine (0.5 mg/kg iv); group D (n = 99) received a single dose of dexamethasone (0.1 mg/kg iv), and group KD (n = 99) received both ketamine (0.5 mg/kg iv) and dexamethasone (0.1 mg/kg iv) at 5 min after the induction of anesthesia. A change in the patient health questionnaire (PHQ)-9 scores on the first and third day after surgery, the duration of anesthesia, the postoperative visual analog scale (VAS) for pain, and the patient controlled analgesia (PCA) consumption were evaluated. RESULTS: Groups K and KD showed a significant reduction in PHQ-9 score on both the first and third day after surgery compared with those recorded preoperatively and in group D (P < 0.01). There were no differences in the group D PHQ-9 scores pre- and post-operatively. The VAS for pain 24 h after surgery and the PCA consumption in group KD decreased significantly compared to the other two groups (P < 0.05). CONCLUSIONS: A single dose of ketamine (0.5 mg/kg) with or without combination with dexamethasone (0.1 mg/kg) give iv 5 min after induction of general anesthetic produced significant improvement in the postoperative mood scores. A single intravenous dose of dexamethasone (0.1 mg/kg) alone did not change postoperative mood scores. The VAS for pain 24 h after surgery and the PCA consumption was significantly lower in patients who received combination of both drugs.