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The variable lymphocyte receptor (VLR) B of jawless vertebrates functions as a secreted Ab of jawed vertebrates and has emerged as an alternative Ab with a single polypeptide chain. After observing an upregulated VLRB response in hagfish immunized with avian influenza virus (AIV) subtype H9N2, we screened AIV H9N2–specific VLRB using a mammalian expression system. To improve the binding avidity of the Ag-specific VLRB to the Ag, we enabled multimerization of the VLRB by conjugating it with C-terminal domain of human C4b-binding protein. To dramatically enhance the expression and secretion of the Ag-specific VLRB, we introduced a glycine–serine linker and the murine Ig κ leader sequence. The practical use of the Ag-specific VLRB was also demonstrated through various immunoassays, detected by anti-VLRB Ab (11G5). Finally, we found that the Ag-specific VLRB decreased the infectivity of AIV H9N2. Together, our findings suggest that the generated Ag-specific VLRB could be used for various immunoapplications.

In hagfish and lampreys, two representative jawless vertebrates, the humoral immunity is directly mediated by variable lymphocyte receptors B (VLRBs). Both monomeric VLRBs are structurally and functionally similar, but their C-terminal tails differ: lamprey VLRB has a Cys-rich tail that forms disulfide-linked pentamers of dimers, contributing to its multivalency, whereas hagfish VLRB has a superhydrophobic tail of unknown structure. Here, we reveal that VLRBs obtained from hagfish plasma have a globular-shaped multimerized form (approximately 0.6 to 1.7 MDa) that is generated by hydrophobic clustering instead of covalent linkage. Electron microscopy (EM) and single-particle analysis showed that the multimerized VLRBs form globular-shaped clusters with an average diameter of 28.7 ± 2.2 nm. The presence of VLRBs in the complex was confirmed by immune-EM analysis using an anti-VLRB antibody. Furthermore, the hydrophobic hagfish C-terminus (HC) was capable of triggering multimerization and directing the cellular surface localization via a glycophosphatidylinositol linkage. Our results strongly suggest that the hagfish VLRB forms a previously unknown globular-shaped antibody. This novel identification of a structurally unusual VLRB complex may suggest that the adaptive immune system of hagfish differs from that of lamprey.

The handling of generated sludge waste during polymer production is one of the main environmental concerns of the polymer industry. An alternative filtration technique was applied to determine the efficiency of different types of filtering media for polymer production. A vibration filter media was replaced with a non-woven fabric filter that was previously used in the refining facility. The purpose of this study is to analyze how much the new filtration affects sludge generation and final production. The application of these alternative filtration techniques have resulted in a significant reduction in the amount of non-recyclable sludge by approximately 77%, while the total amount of polymer production has increased by 41% during the six-year study period. The refining facility saved a total of 617,710 USD/y by changing the filtration system, resulting in an increase in product recovery and a decrease in sludge generation, as well as an improvement in reaction conditions.

The occurrence of fluoride in groundwaters can be influenced by many factors. In Korea, the fluoride-rich groundwaters are normally associated with rock types, especially granite and gneiss. In Gimcheon, high-fluoride groundwaters (up to a maximum of 2.15 mg/L) were observed with bimodal distribution of concentrations. The groundwater in this area showed relatively high concentrations of anthropogenic chemicals such as nitrate, chloride, and sulfate. Statistical analysis showed that fluoride is positively correlated with pH, alkalinity, sodium, and lithium, indicating that the interaction with granite is the main cause enriching its concentration. In Gimcheon, δ18O data of groundwater showed a negative correlation with nitrate and can be used as an indicator of groundwater age. The four samples of fluoride-rich groundwater were plotted in the light δD and δ18O region, showing that they were the result of long water–rock reaction. However, other groundwater with a low-fluoride concentration was evenly distributed throughout all δD and δ18O ranges and did not show a statistically significant correlation with nitrate, indicating possible mixing with another source of fluoride. Considering the influence from the surface on the geochemical characteristics of groundwater in this area, anthropogenic sources including phosphate fertilizer containing fluoride and pesticides may also have partly contributed to the concentrations of fluoride in the low-fluoride groundwater. The scattered distribution of fluoride-rich groundwater and the significant correlation with lithium suggest that pegmatite is the main rock type increasing fluoride concentration in this area.

Immersion lithography has drawn tons of interests as a potential solution for sub-65nm patterning. High refractive index liquid, which is filled in the gap between exposure lens and a photoresist, can improve a resolution through increased effective numerical aperture (NA) of the exposure system. Most attractive liquid for this purpose is water. Our works were conducted as a part of the basic study for immersion lithography and aimed for the verification of leached resist components by water. It was observed that leaching relies largely on the free volume of a polymer and anion size of photoacid generator (PAG). The larger free volume and the smaller anion, the larger T-top resist profile was generated. Additionally, effects of solvents, quenchers and polarity of the polymer were investigated. Detailed results will be reported in this paper.

Post exposure bake temperature sensitivity (PEB sensitivity) is getting important for below 100nm device. There are several factors affecting the PEB sensitivity including acidity and diffusion of photogenerated acid, stiffness and free volume of base polymer, and so on. Among them, the activation energy for deprotection reaction is regarded as the most critical factor. We have investigated the influence of protection group with various activation energies as well as Tg of polymer. Several different protection groups were incorporated into the polymer chain to modify activation energy of the resist. Also, we have investigated the influence of acid diffusion and quencher diffusion ability on PEB sensitivity. Three photoresists were formulated with different concentration of acid diffusion controller to asses the influence of acid diffusion on CD variation. And to evaluate the effect of quencher diffusivity on CD change, photoresist was formulated by adding amines having various different molecular size. Detailed results and new resist with reduced the PEB sensitivity will be reported in this paper.

Hydrophilicity of a resist film is a major property to determine the compatibility of resist film and substrates. By incorporation of polar groups in the side chain of polymer, the hydrophilicity of polymer, eventually, the hydrophilicity of a resist film can be modified. Since most developer for photoresist is aqueous alkaline solution, the polar side groups control not only interaction with a substrate but also dissolution rate of the resist film. We have synthesized model polymers having various polar groups, and investigated the effect of the polarity on the 193nm resist photographic behavior. Acid, lactone, ether, and alcohol were selected as polar groups. Among them, various lactone and alcohol functional groups were selected for further study on the effect of the side group bulkiness. Hydrophilicity of each functional group was estimated by Log P, which can be calculated using simulation program. From the calculation, aliphatic alcohol and lactone have the highest polarity and ether has the lowest. However, the bulkiness of alcohol increases, the polarity is getting lower than that of ether. Polarity and bulkiness of the polar monomers (acid, lactone, ether, and alcohol group) affect wettability against developer, collapse in 1:1 L/S patterns and adhesion to substrates. The resist films have different contact angles by polarity, bulkiness and content of these monomers in polymer. The polymer including lactone group shows excellent lithographic performance and minimizes pattern collapse in 1:1 L/S. Furthermore, we investigated contrast, pattern profile and process margin of 193nm resist according to the polymer polarity.

We fabricated a micro mold using UV-lithography process with a novel mold material, negative PMER. Negative PMER(TOK, PMER N-CA3000) is a chemically amplified negative tone photoresist on a novolak resin base. It can be processed using standard equipment such as standard spin coater, baking with ovens or hotplates, and immersion development tools. Good quality resist patterns of up to 36μm thickness were achieved by means of this equipment in a short time. The conditions of this process were pre-exposure bake of 110 degree(s)C/12min, exposure dose of 675mJ/cm 2 post-exposure bake of 100 degree(s)C/9min, and development for 10min.