Ethylene (C 2 H 4 ) is a crucial plant hormone that regulates fruit ripening and aging. As the only gaseous plant hormone, ethylene has been identified as a significant contributor to produce spoilage, causing economic losses of billions of dollars annually. To address this issue, the development of a biosensor that can accurately and specifically monitor ethylene levels as an indicator of production loss is of paramount importance to the fruit, flower, and vegetable industries, owing to its potential to mitigate losses and increase profits. Consequently, there is an increasing demand for affordable, reliable, and improved methods for rapid and accurate detection and quantification of ethylene. Consequently, the selection of appropriate sensor solutions should specify the requirements and contexts of individual applications. In this review, we explore the recent progress in chemical sensing technologies for ethylene detection and highlight the current research trends and future challenges in this field.

Carbon nanotubes (CNTs) are an exceptional class of nanoparticles owing to their excellent mechanical and electronic properties. They have been applied in various engineering applications. Numerous researchers have examined the effects of CNTs on human health and the environment from various perspectives. Although research in nanotoxicology and nanoecotoxicology is a societal priority, the required experimental methods and approaches are still in the early stages of development, thus presenting a scientific challenge. The current study provides an in-depth analysis of the micromechanical properties of nanocomposite materials consisting of carbon fibers, glass fibers, and CNTs embedded in an epoxy matrix. The analytical method employed is based on a generic approach. As per the results, the carbon-CNT/epoxy hybrid nanocomposite exhibits higher resistance toward mechanical stresses compared with other materials, such as the CNT/epoxy nanocomposite and glass-CNT/epoxy hybrid nanocomposite. These findings are corroborated by Kamae's study, which reports that the utilization of CNT material significantly enhances the interfacial bonding between the carbon fiber and epoxy matrix. The results obtained from this study reveal numerous promising materials that have the potential to be highly valuable in various emerging sectors of society.

The local surface plasmon effects of colloidal cadmium selenide (CdSe) quantum dots (QDs) were observed at a low temperature (approximately 5 K). As the wavelength between the CdSe QDs and metals is precisely tuned, the enhancement effects of CdSe photoluminescence (PL) significantly increase because of the increased coupling effects between the plasmonic fields of the metal surfaces of Au and Ag and the exciton states of a single CdSe QD. The PL enhancement effect of Au was observed to be approximately six times higher than that of Ag because of enhanced coupling. This result demonstrates the importance of wavelength matching in maximizing the surface plasmon effects and achieving enhanced PL in various device applications.

Plasmon-enhanced Raman scattering is crucial for investigating a variety of materials, including chemical and biological molecules.A localized surface plasmon resonance (LSPR) must be designed to strengthen the optical field surrounding the plasmonic structure for sensitive Raman sensing because Raman scattering is proportional to the intensity of the optical field.Recent research has focused on various plasmonic structures, such as nanoparticles on mirrors, nanoparticles, tip-enhanced plasmonic structures, and one-dimensional (1D) nanogaps, to improve Raman scattering by designing LSPR.Furthermore, a 1D nanogap provides an effective optical field enhancement because of the extremely confined optical field and strongly excited LSPR.Moreover, a 1D nanogap enables large-area sensing owing to its one-dimensionally extended nature.In this study, we investigated the strongly enhanced optical field distribution and scattering spectra of a 1D Au nanogap using finite-difference time-domain simulations.In addition, we obtained significantly enhanced Raman scattering signals of a WSe 2 monolayer and brilliant cresyl blue molecules via a 1D Au nanogap.

Babies born prematurely may have difficulty with breathing and nutrition intake because many of their organs are less developed.In particular, childbirth before 32 weeks is known to fatally affect newborn survival and growth.Therefore, when signs of an impending premature birth are observed, delaying delivery through appropriate treatment is critical in the health and quality of life of mothers and newborns.In a previous study, above average concentrations of interleukin (IL) 13 were found to increase the likelihood of premature birth.Therefore, we fabricated anti IL-13 antibody-conjugated graphene field-effect transistor (Immuno field-effect transistor, ImmunoFET) to detect IL-13 protein, specifically.In detail, the response of the ImmunoFET to the target was highly sensitive and dose-dependent with the detection limit of 15 pg mL -1 .Moreover, selectivity tests were performed to demonstrate the interference effects of IL-6 and IL-17, other cytokines associated with premature birth.Despite the existence of high concentrations of nontargets, our sensor was able to detect the target selectively.To the best of our knowledge, this platform is the first ImmunoFET to detect IL-13 based on a graphene field-effect transistor.Our newly fabricated device can be a great diagnostic tool for the preterm birth.

Hot filament chemical vapor deposition (HFCVD) is a well-known process for producing diamond-thin films. The worktable temperature of HFCVD equipment is among the most important requirements for the manufacture of high-quality thin films, but it is difficult to measure that temperature. In this study, worktable temperature was predicted through a three-dimensional numerical simulation considering radiative heat transfer using a commercial computational fluid dynamic code, ANSYS-FLUENT (Ver. 20.1). We also carried out optical diagnosis of temperature of filament surface through two-color pyrometry method. The results showed that difference rates are similar, within 18 %, demonstrating the validity of both filament temperature calculation through thermal fluid analysis and the temperature diagnosis method using two-color pyrometry.

Serotonin is a stress biomarker and is one of the major neurotransmitters, and its concentration in the body is related to psychological functions such as mental illness. In particular, this biomarker is used to indicate depression caused by the increased stress of modern society. Therefore, detection and monitoring technologies are important for tracing concentration changes. In this study, we developed a serotonin antibodyconjugated graphene micropatterned field-effect transistor (SAb-GMFET)-based portable device for on-site or self-diagnosis of serotonin. The SAb-GMFET consisted of a graphene micropatterned channel, SAb for selective detection, and electrodes to supply the voltage. The SAb was immobilized by forming an amide bond with a diamine linker. SAb-GFMET showed high performance of limit of detection of 10 pM within 10 s and exhibited excellent selective detection among the interfering materials. For on-site and self-diagnosis applications, a portable device was developed with a sim chip, and the SAb-GMFET was connected to a printed circuit board using wire bonding. The portable SAb-GMFET showed a similar performance to that of the SAb-GMFET. Therefore, this portable platform can be utilized for point-of-care tests.

We report improved photoelectrochemical water splitting (PEC-WS) using GaN nanowires (NWs) with reverse-mesa structures (RMNWs) formed on Si(111) as a photoanode material.The GaN-RMNW photoanode exhibited a current density of 2.62 mA/cm 2 and an applied photonto-current efficiency of 1.65% at 0.6 V versus a reversible hydrogen electrode.These values are considerably higher than those (1.16 mA/cm 2 and 1.24%) of the photoanode based on GaN NWs with uniform hexagonal-pillar structures.The improved PEC-WS using the GaN-RMNW photoanode is attributed to the increase in the number of carriers participating in the PEC-WS reaction.The increase in the effective carriers is primarily due to the high crystallinity of the GaN RMNWs and the increase in the absorption rate of the incident light by the reverse-mesa structures.In addition, the energy-band structure between the GaN RMNWs and Si(111) promotes the separation of photogenerated carriers.Consequently, it reduces carrier recombination inside the photoanode, thereby enabling a high-performance PEC-WS.

A Ba 0.9 Bi 0.1 TiO 3 solid solution was prepared by substituting 0.1 mole % Bi 2 O 3 at the Ba 2+ sites in BaTiO 3 , and its dielectric properties were investigated. The Ba 0.9 Bi 0.1 TiO 3 solid solution was sintered at 1310 C for 5 h. The stable formation of the perovskite structure was confirmed through X-ray diffraction, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. Unlike pure BaTiO 3 , pyrochlore Bi 2 Ti 2 O 7 was observed in Ba 0.9 Bi 0.1 TiO 3 at approximately 27.1 . Overall, the perovskite structure was well formed. The Ba 0.9 Bi 0.1 TiO 3 solid solution showed typical dielectric properties and followed the modified Curie-Weiss law. In addition, the curve of the dielectric constant vs. temperature showed an extremely gradual change compared to the phase transition behavior of BaTiO 3 .