• Fibers and Polymers
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• v.4 no.3
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• pp.102-106
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• 2003

Crystallization behaviour of blends of different MFI isotactic polypropylenes (PP), and blends of PP with carbon nanofibre have been investigated by DSC and polarizing optical microscope. Both higher MFI PP component and the carbon nanofibre in the blend influence the nucleation activity of the melt during non-isothermal crystallization. In presence of carbon nanofibre, the sherulitic growth rate is highly disturbed. The calculation of nucleation activity indicates that carbon nanofibres act as active substrate for heterogeneous nucleation.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.234-238
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• 2012

Recombinant Escherichia coli displaying organophosphorus hydrolase (OPH) was used to overcome the diffusion barrier limitation of organophosphorus pesticides. A new anchor system derived from the N-terminal domain of ice-nucleation protein from Pseudomonas syringae InaV (InaV-N) was used to display OPH onto the surface. The designed sequence was cloned in the vector pET-28a(+) and then was expressed in E. coli. Tracing of the expression location of the recombinant protein using SDS-PAGE showed the presentation of OPH by InaV-N on the outer membrane, and the ability of recombinant E. coli to utilize diazinon as the sole source of energy, without growth inhibition, indicated its significant activity. The location of OPH was detected by comparing the activity of the outer membrane fraction with the inner membrane and cytoplasm fractions. Studies revealed that recombinant E. coli can degrade 50% of 2 mM chlorpyrifos in 2 min. It can be concluded that InaV-N can be used efficiently to display foreign functional protein, and these results highlight the high potential of an engineered bacterium to be used in bioremediation of pesticide-contaminated sources in the environment.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.403-409
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• 2022

In biological particles such as Fusarium species, ice nucleation activity (INA) has been observed. Fusarium strains isolated from apple declined trees in Korea were identified with a multilocus sequence analysis using the tef1 and rpb1 genes. Droplet-freezing and tube-freezing assays were used to determine the INA of the strains, using Pseudomonas syringae pv. syringae KACC 21200 as a positive control and resulting in seven INA+ fungal strains that were identified as F. tricinctum (KNUF-21-F17, KNUF-21-F18, KNUF-21-F29, KNUF-21-F32, KNUF-21-F38, KNUF-21-F43, and KNUF-21-F44). The effect of Fusarium INA+ KNUF-21-F29 was compared to that of INA- strains on Chrysanthemum morifolium cv. Shinma explants. A higher callus formation and no-shoot formation were observed, suggesting that fungal INA could play a role in cold injuries and be a factor to consider in rapid apple decline. To the best of our knowledge, this is the first report of INA fungal strains isolated in Korea.

• The Korean Journal of Mycology
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• v.50 no.4
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• pp.255-262
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• 2022

In this study, the fungal strain KNUF-21-F39 was isolated from a declined apple tree (Malus domestica) in the Chungcheongbuk province in Korea. The strain KNUF-21-F39 presented a slow growth rate and a variety of macroconidia shapes and sizes ranging from ovoid to fusoid and 1- to 5-septate, primarily showing 3- and 4-septate, with "S" -shaped macroconidia rarely observed. The strain was identified based on morphological characteristics along with phylogenetic analysis performed using the internal transcribed spacer region (ITS) and partial sequences of translation elongation factor 1-α (tef1), RNA polymerase largest subunit (rpb1), and calmodulin (cal) genes. The fungal strain KNUF-21-F39 was identified as Fusarium diversisporum, which has not been previously reported in Korea. The ice nucleation activity (INA) of the strain was also evaluated, identifying the strain as positive for INA. This is the first report characterizing F. diversisporum as an IN-active fungal species.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.62-68
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• 1994

Isolation, indentification, bioassay and distribution of ice nucleation active(INA) bacteria were done on branch rot of mulberry which was severely developed after harvest of mulberry branches in autumn. Twelve isolates and two isolates out of thirty-six isolates had ice nucleation activity from -5$^{\circ}C$ to -1$0^{\circ}C$, and over -5$^{\circ}C$, respercively. Isolates which formed ice nucleation from -5$^{\circ}C$ to -1$0^{\circ}C$ were not inclined to injure tomato and corn seedlings. However, Two isolates, SE9316 and SE9338 which formed ice nucleation over -5$^{\circ}C$ injured mulberry, tomato and corn seedlings. SE9316 and SE9338 were identified as Pseudomonas syringae based on the morphological, cultural and biochemical characteristics. Populations of ice nucleation active bacteria, fluorecent pseudomonads, were higer in February and April, but they decreased in May. Populations decreased as they become distant from the center of the symptom. The bacterial populations of all sampling times and sites were higer than 105 cfu/g which was enough to induce frost injury.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.326-336
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• 1997

Four ice nucleation-active bacteria (INA-bacteria), Pseudomonas syringae, Xanthomonas campestris, Escherichia coli JM109/pEIN229 and Gluconobacter oxydans/pKIN230, were treated with heat, pressure and gamma-irradiation to compare viability and their ice nucleation activity (INA) after sterilization. Gamma-irradiated INA-bacteria showed the least decrease in T90 value (the temperature at which the 90% of drops are frozen). According to cumulative INA spectra, gamma-irradiated INA-bacteria showed little decrease in class A ice nuclei $(nucleate\;H_{2}O\;at\;higher\;than\;-5^{\circ}C)$, pressurized INA-bacteria showed more than 90% decrease in class A ice nuclei, and heat-treated INA-bacteria barely showed class A ice nuclei. Differential scanning calorimetry (DSC) was used to examine the effect of INA-bacteria on the thermophysical properties of water at freezing temperature. Freezing peaks were appeared at about $11{\sim}15^{\circ}C$ higher on thermograms and enthalpies of phase change were decreased for the water containing INA-bacteria compared with the pure water, while melting peaks were not shifted. INA measured by DSC method were significantly correlated with INA measured by drop freezing method $(R^{2}>0.993,\;p<0.0001)$, indicating that DSC can be used as a new, simple and precise method for measuring INA.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.84-91
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• 1997

Diamond film was deposited on Mo substrate at atmospheric pressure using a combustion flame apparatus with the addition of $H_2$. With the substrate temperature, the nucleation density of the substrate was increased. At temperatures above $1000^{\circ}C$, some of diamond was partly converted into graphite and etched by hydrogen atoms. With an increase of the $C_2H_2/O_2$ ratio, the nucleation density was increased. But crystals were cauliflower-shaped and a large number of amorphous carbon were deposited. With the addition of $H_2$, the nucleation density of diamond was increased by the improvement of surface activity. Diamond film of high crystallinity was deposited by etching amorphous carbon. With an increase of deposition time, the thickness of diamond film was increased.

• Macromolecular Research
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• v.13 no.1
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• pp.19-29
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• 2005

Polymer composites based on a thermotropic liquid-crystalline polymer (TLCP) and poly(butylene terephthalate) (PBT) were prepared using a melt blending process. Polymer composites consisting of bulk cheap polyester with a small quantity of expensive TLCP are of interest from a commercial perspective. The interactions between the PBT chains and the flexible poly(ethylene terephthalate) (PET) units in the TLCP phase resulted in an improvement in the compatibility of PBT/TLCP composites. TLCP droplets deformed and fragmented into smaller droplets in the PBT/TLCP composites, which resulted in TLCP fibrillation through the effective deformation of the TLCP droplets. The nucleation activities of the PBT/TLCP composites increased by adding even a small amount of the TLCP component.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.180-186
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• 1987

Cell suspensions of two isolates of Pseudomonas syringae. PS8401 from sweet persimon and PS8402 from tea plant, were active in ice nucleation at -2.5 and $-3.8^{\circ}C$, respectively. Ice nucleation at those temperature was, using micropipette method, detected in suspensions ($10^8$ olony forming unit/ml of distilled water) of cells that had been grown on nutrient agar supplemented with $2.5\%$ glycerol. Using the same method, on the other hand, the freezing temperature of distilled water only was approx. $-21.8^{\circ}C$, and those of various plant saps including corn were lower than $-11.6^{\circ}C$. Corn seedlings sprayed with cell suspensions $(10^8\;cfu/ml)$ of nutrient broth) of PS8401 began to be damaged at $-2^{\circ}C$ and were almost completely damaged at $-4^{\circ}C$, whereas seedlings sprayed with nutrient broth only were not injured until the temperature down to $-9^{\circ}C$. Amounts of frost damage measured 48 hr after application of PS8401 suspensions increased as applied bacterial cell densities were increased. Ice-nucleation activity of the cell suspensions in vitro increased with increasing the number of cells in suspension. The activity also affected by growth-medium composition or growth-temperature. Ice nucleation thus occured at -4.0, -4.4 and $-7.2^{\circ}C$ in suspensions $(10^2\;cfu/ml)$ of PS8401 that had been grown at$25\%$ nutrient agar with $2.5\%$ glycerol, nutrient agar with $2.5\%$ glucose and nutrient agar only, respectively, and occured at -4.0 and $-7.6^{\circ}C$ in suspensions $(10^2\;cfu/ml)$ of PS8401 hat had been grown on nutrient agar with $2.5\%$ glycerol at $15\~25^{\circ}C$ and $30^{\circ}C$, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.6
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• pp.311-316
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• 2002

Two different approaches, namely two-step deposition process and Bias-Enhanced Nucleation (BEN) technique have been examined for deposition of high quality diamond thin film on polycrystalline Ni which has low chemical activity with the carbon neutrals provided from the $CH_4/H_2$mixtures. A two-step deposition process, consisted of pre-deposition of soot layer at lower temperatures and subsequent deposition at higher temperature condition, has been developed to deposit diamond layer directly on Ni substrate. Diamond particles were observed after deposition step at $925^{\circ}C$ for 5 hours and those particles seem to be nucleated from the soot layer pre-deposited at lower temperatures ($810^{\circ}C$). Diamond particles of a substantial size were found on Ni substrate after biasing -220 V for 10 minutes and subsequent deposition for 2 hours while no diamond particles were observed under the conditions without applied bias.