Owing to the great demand for portable and wearable chemical sensors, the development of all-solid-state potentiometric ion sensors is highly desirable considering their simplicity and stability. However, most ion sensors are challenged by the penetration of water and gas molecules into ion-selective membranes, causing unstable and undesirable sensing performances. In this study, a hydrophobic ionic liquid-modified graphene (Gr) sheet was prepared using a fluid dynamics-induced exfoliation and functionalization process. The high hydrophobicity and electrical double-layer capacitance of Gr make it a potential solid-state ion-to-electron transducer for the development of potentiometric sodium-ion ( Na+) sensors. The as-prepared Na+ sensors effectively prevented the formation of the water layer and penetration of gas species, resulting in stable and high sensing performances. The Na+ sensors showed a Nernstian sensitivity of 58.11 mV/[Na+] with a low relative standard deviation (0.46), fast response time (5.1 s), good selectivity (K < 10− 4), and good durability. Furthermore, the Na+ sensor demonstrated its feasibility in practical applications by measuring accurate and reliable ion concentrations of artificial human sweat and tear samples, comparable to a commercial ion meter.

A facile and efficient method was developed to prepare highly stretchable and conductive graphene conductors with wrinkled structures by the mechanical stretching and shrinking of elastomeric substrates, in which graphene inks were printed on a prestretched elastomeric substrate. Stretchable and exfoliated graphene inks were prepared by mixing graphite and Ecoflex in a shear-assisted fluid dynamics reactor. The resultant graphene conductor exhibited excellent stretchability at 150% strain and high electrical conductivity of 64 ± 1.2 S m− 1. The resistance of the conductor did not change in bent, twisted, and stretched states. The resistance did not change during 10,000 cycles of stretching/releasing, with a maximum strain of 150%. Based on the graphene conductor, a stretchable conductometric sensor with a two-electrode configuration was fabricated to measure impedance changes at different concentrations of electrolyte ions. This sensor exhibited a good and linear sensitivity curve (298.61 Ω mM− 1, R2 = 0.999) in bent and stretched states.

Mitochondrial genomes of three specimens of Gadus chalcogrammus Pallas 1,814 from Korea and Japan were completely analyzed by the primer walking method. They were 16,570~16,571 bp in length, each comprising 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Their gene orders were identical to those of conspecific specimens, but exhibited unique haplotypes. In the phylogenetic tree, the juvenile Korean and adult Japanese specimens were separated from the dominant clade composed of specimens from Japan, Korea, the Bering Sea, and the Arctic, including the adult Korean specimen.

We report potentiometric performances of ion-to-electron transducer based on reduced graphene oxide (RGO) for application of all-solid-state potassium ion sensors. A large surface area and pore structure of RGO are obtained by a hydrothermal self-assembly of graphene oxide. The extensive electrochemical characterization of RGO solid contact at the interface of ionselective membrane and gold electrode shows that the potassium ion-selective electrode based on RGO had a high sensitivity (53.34 mV/log[K+]), a low detection of limit (− 4.24 log[ K+], 0.06 mM) a good potential stability, and a high resistance to light and gas interferences. The potentiometric K+- sensor device was fabricated by combining of screen-printed electrodes and a printed circuit board. The K+- sensor device accurately measures the ion concentration of real samples of commercial sports drinks, coke and orange juice, and then transfers the collected data to a mobile application through a Bluetooth module. The screen-printed ion sensors based on RGO solid contact show a great potential for real-time monitoring and point-of-care devices in human health care, water-treatment process, and environmental and chemical industries.

The nesting behavior, reproduction, fruit set and shape of O. cornifrons varied significantly with the released sex ratio of O. cornifrons. A female : male sex ratio of 1 : 2 was resulted in a 3.4 to 6.7 fold higher than other sex ratio in a nesting behavior. A ratio of 1 : 2 resulted in a 1.2-fold nesting rate, which was slightly higher than other nesting rates. Releasing only males resulted in a 2.4-fold greater amount of fruit set in non-pollinated sites. A sex ratio of 1 : 2 gave a slightly higher shape index and a 1.2 to 1.6-fold lower asymmetric index than other sex ratios. There was no significant difference between female release numbers in fruit set, and 100 to 200 females gave a slightly higher shape index than 400 females. Thus, we determined that 200 females should be released per 2,000㎡ and that the sex ratio of females to males should be 1 : 2.

We investigated pollination and foraging activities of honeybee (Apis mellifera L.) and bumblebee (Bombus terrestris L.) during flowering season of the asian pear (Pyrus pyrifolia N.) under different weather conditions. There was no significant statistical difference about the pollination activities of two species. However, the pollination activities of bumblebee were more active than those of honeybee under low temperature and rainfall period. The activities of honeybee and bumblebee were more influenced by temperature than other factors (i.e. illumination and wind velocity). Honeybee was more sensitive to temperature and illumination than bumblebee. At low temperatures (<20℃) on cloudy days (<30,000 lux) with a certain wind velocity (>4.0 m/s), the pollination activity of the honeybee was lower twice than that of bumblebee.

Ixodid ticks are notorious as the vector of severe fever with thrombocytopenia syndrome virus (SFTSV) in Korea. To confirm the transovarial transmission of SFTSV, we collected blood-fed adult ticks from animals in SFTS case reported area of Jeju island in 2015. A total of 476 ticks were collected from four host animal species, horse (81.3%), dog (9.0%), roe deer (7.1%) and wild boar (2.5%). They were identified as 1 genus and 2 species, Haemaphysalis longicornis (87.8%) and H. flava (12.2%). Among them, 131 adults hatched their eggs successfully. The body weight of females was highly correlated with the number of egg masses laid (P < 0.05). We confirmed that one adult H. flava was infected with SFTSV and its infection rate was 0.77%. The eggs of the SFTSV-infected adults also were infected with SFTSV and its transovarial transmission was confirmed. This result suggests that the parent generation of H. flava could transmit SFTSV transovarially into their F1 progeny and H. flava might be one of major vectors of SFTSV in Korea.

We investigated the distribution of ixodid ticks in severe fever with thrombocytopenia syndrome (SFTS) case reported areas using flagging method from May to November 2014 in Korea. We collected 13,471 ixodid ticks with 2 genera and 3 species. Among them, Genus Haemaphysalis and Ixodes accounted for 99.9% (13,455) and 0.1% (16), respectively. Genus Haemaphysalis consisted of 2 species, H. longicornis (96.2%) and H. flava (3.7%). I. nipponensis was only collected in Genus Ixodes. H. longicornis was the dominant species (over 90%) in most study areas. Ixodid ticks were evenly distributed at various environmental sites, such as residences, hills, grassfields, fields, graves, copses, other sites. The further study on SFTSV infection in ixodid ticks will be needed.