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In 2018, a bacterial disease complex composed of bleached spots and soft rot–blight on onion seedlings was observed in nursery beds in Changnyeong, a major onion-producing county in South Korea. Four bacteria isolated from the diseased lesions were identified: Pseudomonas viridiflava, Acidovorax avenae subsp. avenae, Pantoea ananatis, and Xanthomonas axonopodis, respectively. We referred to the four strains as a “bacterial disease complex” because they were isolated from the same sample with multiple symptoms. We examined the synergistic activity among the four strains to understand their relationships and roles. We monitored in vivo bacterial population density and disease progression after artificially inoculating the bacteria on onion seedlings at a temperature of 22 or 28°C. The disease pattern progressed sooner at 28 than at 22°C (by an average of 4 to 6 days). The rate of disease progression induced by inoculation of P. ananatis alone was consistent with that induced by coinoculation of P. ananatis with the other strains, regardless of the temperature (22 or 28°C). The in vivo growth of P. ananatis on onion seedlings was not different after inoculation alone versus together with the other strains. The rate of disease progression induced by P. viridiflava was similar when inoculated alone and when inoculated with other tree strains at 28°C, but disease progression induced by inoculation alone was slower at 22°C. The in vivo growth of P. viridiflava or X. axonopodis on onion seedlings decreased rapidly or gradually, respectively, when inoculated with the other strains. Coinfection with the other three strains had repression effects on the growth of P. viridiflava, a slight effect on X. axonopodis, and no effect on P. or A. avenae subsp. avenae in vivo. These results indicate that the strains coexist or interact antagonistically, rather than synergistically, depending on the conditions. These results were consistent with the results of the in vitro growth inhibition assay, in which P. viridiflava growth was inhibited by X. axonopodis or P. ananatis. These results also confirmed that X. axonopodis is present on bleached spots and P. viridiflava on soft rot–blight lesions, and that P. viridiflava and P. ananatis cause soft rot–blight but do not coexist. A. avenae subsp. avenae is a minor causative pathogen of bleached spots on onion seedlings, but it is not significantly affected by temperature and has no antagonistic or synergistic interactions with X. axonopodis.

Burkholderia glumae causes panicle blight of rice (grain rot in Japan and Korea), and the severity of damage is increasing worldwide. During 2017 and 2018, 137 isolates of B. glumae were isolated from symptomatic grain rot of rice cultivated in paddy fields throughout South Korea. Genetic diversity of the isolates was determined using transposase-based PCR (Tnp-PCR) genomic fingerprinting. All 138 isolates, including the B. glumae BGR1 strain, produced toxoflavin in various amounts, and 17 isolates produced an unidentified purple or orange pigment on Luria-Bertani medium and casamino acid-peptone-glucose medium, respectively, at 28°C. Transposase-based PCR genomic fingerprinting was performed using a novel primer designed based on transposase (tnp) gene sequences located at the ends of the toxoflavin efflux transporter operon; this method provided reliable and reproducible results. Through Tnp-PCR genomic fingerprinting, the genetic groups of Korean B. glumae isolates were divided into 11 clusters and three divisions. The Korean B. glumae isolates were mainly grouped in division I (73%). Interestingly, most of the pigment-producing isolates were grouped in divisions II and III; of these, 10 were grouped in cluster VIII, which comprised 67% of this cluster. Results of a phylogenetic analysis based on tofI and hrpB gene sequences were consistent with classification by Tnp-PCR genomic fingerprinting. The BGR1 strain did not belong to any of the clusters, indicating that this strain does not exhibit the typical genetic representation of B. glumae. B. glumae isolates showed diversity in the use of carbon and nitrogen sources, but no correlation with genetic classification by PCR fingerprinting was found. This is the first study to analyze the geographical distribution and genetic diversity of Korean B. glumae isolates.

Realizing a clinical-grade electronic medicine for peripheral nerve disorders is challenging owing to the lack of rational material design that mimics the dynamic mechanical nature of peripheral nerves. Electronic medicine should be soft and stretchable, to feasibly allow autonomous mechanical nerve adaptation. Herein, we report a new type of neural interface platform, an adaptive self-healing electronic epineurium (A-SEE), which can form compressive stress-free and strain-insensitive electronics-nerve interfaces and enable facile biofluid-resistant self-locking owing to dynamic stress relaxation and water-proof self-bonding properties of intrinsically stretchable and self-healable insulating/conducting materials, respectively. Specifically, the A-SEE does not need to be sutured or glued when implanted, thereby significantly reducing complexity and the operation time of microneurosurgery. In addition, the autonomous mechanical adaptability of the A-SEE to peripheral nerves can significantly reduce the mechanical mismatch at electronics-nerve interfaces, which minimizes nerve compression-induced immune responses and device failure. Though a small amount of Ag leaked from the A-SEE is observed in vivo (17.03 ppm after 32 weeks of implantation), we successfully achieved a bidirectional neural signal recording and stimulation in a rat sciatic nerve model for 14 weeks. In view of our materials strategy and in vivo feasibility, the mechanically adaptive self-healing neural interface would be considered a new implantable platform for a wide range application of electronic medicine for neurological disorders in the human nervous system., Electronic implantable devices should be soft and stretchable, such that nerves can adapt mechanically and autonomously. Here, the authors present an adaptive self-healing electronic epineurium which can form compressive stress-free and strain-insensitive electronics-nerve interfaces.

The African spear or cylindrical snake plant (Sansevieria cylindrica) is commonly used as an ornamental indoor succulent plant. In May 2019, we observed bacterial blight in S. cylindrica grown for interior decoration and air purification in Jinju, South Korea. These symptoms eventually led to leaf desiccation. Similar leaf blight symptoms have been frequently documented on social media; however, as an imported species, the pathogens of S. cylindrica have not been reported in South Korea. Based on pathogenicity tests; levan production, oxidase production, pectinolytic activity, arginine dihydrolase production, and tobacco hypersensibility tests; analytical profile index API tests; and phylogenetic analysis based on multi-locus sequence analysis using the 16S rRNA, gyrB, rpoD, and rpoB gene sequences, we identified the causative pathogen as Pseudomonas sp. This study is the first to report leaf blight caused by Pseudomonas sp. on S. cylindrica.

Anthracnose was observed on postharvest avocados (Persea americana) in a commercial market in Jinju, South Korea, in 2019. Symptoms included soft rot and sunken lesions leaking necrotic fluid. Oran...

In 2018, bacterial shoot blight was observed on Asian pear trees (Pyrus pyrifolia) in an orchard in Jinju, South Korea. The young pear shoots were infected and showed shoot blight symptoms: the shoot tips shriveled and turned tan in color, and this spread from the shoot tip down the stem and into the leaves. The causal pathogen was isolated from the diseased lesions and identified as Pseudomonas cerasi based on API tests and multilocus sequence analysis (MLSA) using the 16S rRNA, gyrB, rpoB, and rpoD gene sequences. The symptoms after artificial inoculation were identical to natural field symptoms, whereas negative control plants were asymptomatic. Bacteria were re-isolated from the artificially induced lesions on blossoms and shoots, and their identity was confirmed by rpoD sequencing. This is the first report of bacterial shoot blight on pear tree caused by Pseudomonas cerasi Griffin in the world.

Highly stretchable fiber strain sensors are one of the most important components for various applications in wearable electronics, electronic textiles, and biomedical electronics. Herein, we present a facile approach for fabricating highly stretchable and sensitive fiber strain sensors by embedding Ag nanoparticles into a stretchable fiber with a multifilament structure. The multifilament structure and Ag-rich shells of the fiber strain sensor enable the sensor to simultaneously achieve both a high sensitivity and largely wide sensing range despite its simple fabrication process and components. The fiber strain sensor simultaneously exhibits ultrahigh gauge factors (∼9.3 × 105 and ∼659 in the first stretching and subsequent stretching, respectively), a very broad strain-sensing range (450 and 200% for the first and subsequent stretching, respectively), and high durability for more than 10 000 stretching cycles. The fiber strain sensors can also be readily integrated into a glove to control a hand robot an...

Grey mould is an important necrotrophic fungal pathogen that causes huge economic losses in agriculture. Many types of bacteria are used for biological control of grey mould via competition for space or nutrients and/or the production of antifungal metabolites. Oxalate is a key component of virulent necrotic fungal pathogens. In this study, we isolated non-antifungal oxalate-degrading bacteria (ODB) from the surfaces of oxalate-rich spinach and strawberries to investigate their ability to control necrotic fungal pathogens such as grey mould. A total of 36 bacteria grown on oxalate minimal (OM) agar plates were tested for oxalate-degrading activity. Five isolates exhibiting the highest oxalate degradation activity were subjected to molecular identification using 16S rRNA gene sequencing. Two isolates exhibiting non-antifungal activity were subjected to disease suppression assays using Arabidopsis–Botrytis systems. The isolate Pseudomonas abietaniphila ODB36, which exhibited significant plant protective ability, was finally selected for further investigation. Based on whole-genome information, the pseudomonad oxalate degrading (podA) gene, which encodes formyl-CoA transferase, was analysed. The podA− mutant did not inhibit Botrytis infection and oxalate toxicity; the defects were recovered by podA complementation. Purified PodA–His converted oxalate to formate and eliminated oxalate toxicity. These results indicate that P. abietaniphila ODB36 and PodA enzyme are associated with various aspects of grey mould disease inhibitory effects.

In 2018, severe bacterial blight was observed on Dracaena sanderiana plants imported and cultivated by a commercial nursery in Jinju, South Korea. This indoor plant is popularly grown for indoor air purification to prevent sick building syndrome (SBS). The diseased plants had severe blight symptoms, with leaf chlorosis and crumpling of stem and leaves. To identify the causal agent, we performed bacterial isolation, pathogenicity tests, physiological analysis, sequencing of the 16S rRNA region and recA gene, and phylogenetic analysis; the bacterial pathogen was identified as Burkholderia cepacia. This is the first report of bacterial blight on D. sanderiana caused by B. cepacia. Although there is no clear epidemiological information on the inoculum source, the recent occurrence of the disease indicates that B. cepacia is a potential threat to the production of indoor dracaena plants, which are increasingly used for air purification in SBS. Because D. sanderiana is grown in indoor living spaces, B. cepacia infection could threaten human health as well.

Agrobacterium-mediated plant galls are often misdiagnosed as nematode-mediated knots, even by experts, because the gall symptoms in both conditions are very similar. In the present study, we developed biosensor strains based on agrobacterial opine metabolism that easily and simply diagnoses Agrobacterium-induced root galls. Our biosensor consists of Agrobacterium mannitol (ABM) agar medium, X-gal, and a biosensor. The working principle of the biosensor is that exogenous nopaline produced by plant root galls binds to NocR, resulting in NocR/nopaline complexes that bind to the promoter of the nopaline oxidase gene (nox) operon and activate the transcription of noxB-lacZY, resulting in readily visualized blue pigmentation on ABM agar medium supplemented with X-gal (ABMX-gal). Similarly, exogenous octopine binds to OccR, resulting in OoxR/octopine complexes that bind to the promoter of the octopine oxidase gene (oox) operon and activate the transcription of ooxB-lacZY, resulting in blue pigmentation in the presence of X-gal. Our biosensor is successfully senses opines produced by Agrobacterium-infected plant galls, and can be applied to easily distinguish Agrobacterium crown gall disease from nematode disease.

Salmonella enterica outbreaks in sprouts originate from contaminated seeds; conventional prevention technologies have been reported from many research institutes. In this study, we applied a biological control approach to inhibit S. enterica growth using the seed-dwelling non-antagonistic bacteria. We isolated non-antibacterial seed-dwelling bacteria from vegetable sprouts. A total of 206 bacteria exhibiting non-antibacterial activity against S. enterica were subjected to alfalfa sprout development tests. Eight isolates exhibiting no deleterious effect on the growth of alfalfa sprouts were tested for S. enterica growth inhibition on alfalfa seeds and sprouts, and an isolate EUS78 was finally selected for further investigation. Based on 16S rRNA, gyrB, and rpoB gene sequence analyses, strain EUS78 was identified as Erwinia persicina. In population competition, the S. enterica population increased by3 log CFU/g after 6 days of alfalfa sprout growth, whereas S. enterica growth was significantly inhibited by treatment with EUS78 (P .05). This effect of S. enterica growth inhibition by EUS78 was sustained until the end of the alfalfa sprout harvest. Overall, bacterial strain EUS78 significantly reduced S. enterica growth on alfalfa sprouts in a manner consistent with competitive exclusion. These findings led us to monitor EUS78 behavior on seeds during early sprout development using fluorescence and scanning electron microscopy. Strain EUS78 initially colonized alfalfa sprout seed coat edges, cotyledons, and finally root surfaces during early sprout germination. As alfalfa sprouts grew, EUS78 bacterial cells established colonies on newly emerged plant tissues such as root tips. The results of this study suggest that strain EUS78 has potential as a biological control agent to inhibit S. enterica contamination in the sprout food industry.

Sweet crab apple (Malus coronaria) is a popular ornamental tree planted in gardens and urban forests in South Korea. In 2018, severe symptoms were observed on street plantings of sweet crab apple in Jinju, South Korea including shoot blight: shoot tips, twigs and foliage of infected trees turned brown, and dried completely. The causal agent isolated from the disease lesions was identified as Pseudomonas viridiflava based on biochemical tests, pathogenicity, and 16S rRNA and rpoD gene sequencing. On artificial inoculation, this pathogen not only caused shoot blight on sweet crab apple, but also bulb rot and leaf blight on onion. Here, we report the occurrence of bacterial shoot blight caused by P. viridiflava in sweet crab apple for the first time in the world.

Over a 3-year period (2015–2017), sclerotium rot was observed on purple wood sorrel (Oxalis purpurea) in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services, Jinju, South Korea. Infected plants exhibited blight and rot symptoms. White mycelial mats spread over lesions, and numerous sclerotia formed on the petiole near the soil line. Sclerotia were globoid in shape, 1–3 mm in size, and white to brown in color. The optimum temperature for mycelial growth and sclerotium formation on potato dextrose agar (PDA) was 30 °C and the hyphal width was 4–8 μm. Typical clamp connections were observed in the hyphae of fungi grown on PDA. Molecular identification was conducted by sequencing and analysis of the complete internal transcribed spacer (ITS) rDNA sequence of the causal fungus. On the basis of mycological characteristics, molecular identification, and pathogenicity to host plants, this fungus was identified as Athelia rolfsii. This is the first report of sclerotium rot on purple wood sorrel caused by A. rolfsii.

Persistent memory (PM) is rapidly emerging as a promising technology with its useful properties such as durability, DRAM-like performance, and byte addressability. However, programming PM is challenging because programmers need to manually orchestrate all the persists with the cache flush operations and persist barriers to ensure the correct execution of their code. To improve the programmability of PM, prior work has extensively investigated the hardware and software techniques for persistent transactions. While insightful, the existing techniques either significantly increase hardware complexity due to the intrusive modifications of the processors, caches, and memory hierarchy or incur significant performance overheads due to the transactional activities solely performed in software. To bridge this gap, this work proposes a hybrid system called HAPT, hardware-accelerated persistent transactions. HAPT accelerates the address translation process for aliased memory operations based on the alias management unit (AMU), which is a lightweight hardware structure. HAPT performs most of the transactional activities in software, achieving low hardware complexity and high flexibility. Our quantitative evaluation demonstrates that HAPT significantly outperforms the state-of-the-art software system for persistent transactions and continues to provide large performance gains even when the AMU is configured with small capacity or long access latency.

To achieve higher performance and energy efficiency, GPGPU architectures have recently begun to employ hardware caches. Adding hardware caches to GPGPUs, however, does not automatically guarantee improved performance and energy efficiency due to the thrashing in small hardware caches shared by thousands of threads. While prior work has proposed warp scheduling and cache bypassing techniques to address this issue, relatively little work has been done in the context of advanced cache indexing. To bridge this gap, this work investigates the feasibility of advanced cache indexing for high-performance and energy-efficient GPGPU computing. We first discuss the design and implementation of static and adaptive cache indexing schemes for GPGPUs. We then quantify the effectiveness of the advanced indexing schemes using GPGPU benchmarks. Our quantitative evaluation demonstrates that the advanced cache indexing schemes are promising in that they significantly outperform the conventional cache indexing scheme. In addition, for a subset of cache-sensitive benchmarks, the adaptive indexing scheme substantially outperforms the static indexing scheme by effectively identifying and utilizing high-quality indexing bits based on runtime information. Finally, our evaluation shows that the effectiveness of advanced cache indexing is sensitive to different warp schedulers, motivating further research on coordinated cache indexing and warp scheduling techniques.

A cryogenic cooling system is essential for high temperature superconducting (HTS) apparatus because cryogenic temperature is generated by using a cryocooler or cryogen. The cryogen method is widely applied to various HTS apparatus because its thermal stability is higher than that of the cryocooler. Furthermore, the cryogen not only performs cooling but also insulates electrically. Thus, the insulation performance of an HTS apparatus relies heavily on the insulation characteristics of cryogen. This study examines the insulation characteristics of cryogens to be applied to HTS apparatus, using nitrogen and argon in liquid and solid state as cryogen. Their electrical characteristics such as the flashover discharge and breakdown are also investigated and compared. We also discuss whether nitrogen and argon in solid state are applicable to HTS apparatus as cryogens.

A high-temperature superconducting (HTS) DC cable system has attracted a great deal of interest from the view point of low loss, dense structure and large capacity compared to HTS AC cable system. It has a HTS cable and a termination. A HTS DC cable system consists of a conductor, cooling system and electrical insulation. To realize the HTS DC cable system, it is important to study not only high current capacity and low loss of conductor but also optimum electrical insulation at cryogenic temperature. The electrical insulation technology of HTS DC cable and termination must be solved for the long life, reliability and compact of cable. In this paper, we will discuss mainly on the electrical insulation characteristics and the insulation design of 220 kV class HTS DC cable. Voltage-time (V-t) characteristics of laminated polypropylene paper (PPLP) in LN2 were studied. Furthermore, the surface flashover characteristics of glass fiber reinforced plastic (GFRP) for termination insulators under DC and lightning impulse voltage were studied.

This study examined the effects of external pressures on the thermal and electrical stabilities of stacked GdBCO CCs through quench tests. The minimum quench energies and two-dimensional normal zone propagation velocities of stacked GdBCO CCs connected electrically in series under various external pressures were examined. The quench test results showed that the minimum quench energy increased with increasing the external pressure. Longitudinal normal zone propagation velocities were greater than transverse normal zone propagation velocities. Moreover, normal zone propagation velocities increased with increasing applied pressure implying that applied pressure resulted in increased layer-to-layer thermal contact that allowed hot spots to dissipate more easily.