기체 분리막의 상업적 발전은 CO2 분리 효율을 향상시키는 데 중요한 역할을 한다. 고분자량 PEO (high-Mw PEO)는 높은 CO2 용해도, 가격 경쟁성 및 견고한 기계적 특성을 가져 분리막 제조용 고분자로 유력하지만 그 특유의 결정성 으로 인해 기체 분리막에 응용이 어렵다. 본 연구에서는 결정성 감소를 위해 다양한 고분자 첨가제를 고분자량 PEO에 혼합 하는 방법을 제시하였다. 폴리에틸렌글리콜(PEG), 폴리프로필렌글리콜(PPG), 폴리아크릴산(PAA) 및 폴리비닐피롤리돈(PVP) 과 같은 상업적으로 이용 가능하고 섞임성이 좋은 수용성 고분자를 첨가제로 사용하여 PEO 결정성을 감소시킴으로써 가스 분리 성능을 향상시키고자 하였다. PEG 및 PPG의 경우 PEO의 결정 구조를 억제하지 못하고 분리막의 결함을 초래하였으나, PAA 및 PVP는 PEO의 결정 구조를 바꿔 결함이 없는 분리막을 제조하는 데 성공하였다. 고분자량 PEO 혼합막의 결정 구조 변화와 기체 분리 성능의 상관관계를 조사하여 본 연구의 결과와 이전에 기록된 결과를 바탕으로 고분자량 PEO에 대한 첨가 제 고분자의 설계 및 선택에 대한 통찰력을 제공하며, 이를 통해 비용 효율적이고 상업적으로 실용적인 CO2 분리막을 제조하 고자 하였다.

Plants synthesize antioxidant compounds as a defense mechanism against reactive oxygen species. Recently, plant-derived antioxidant compounds have attracted attention due to the increasing consumer awareness in the heath industry. However, traditional methods for measuring the antioxidant activity of these compounds are time-consuming and costly. Therefore, our study constructed a quantitative structure-activity relationship (QSAR) model that can predict antioxidant activity using graph convolutional networks (GCN) from plant structural data. The accuracy (Acc) of the model reached 0.6 and the loss reached 0.03. Although with lower accuracy than previously reported QSAR models, our model showed the possibility of predicting DPPH antioxidant activity in a wide range of plant compounds (phenolics, polyphenols, vitamins, etc.) based on their graph structure.

Epoxy-based composites find extensive application in electronic packaging due to their excellent processability and insulation properties. However, conventional epoxy-based polymers exhibit limitations in terms of thermal properties and insulation performance. In this study, we develop epoxy-based siloxane/silica composites that enhance the thermal, mechanical, and insulating properties of epoxy resins. This is achieved by employing a sol–gelsynthesized siloxane hybrid and spherical fused silica particles. Herein, we fabricate two types of epoxy-based siloxane/ silica composites with different siloxane molecular structures (branched and linear siloxane networks) and investigate the changes in their properties for different compositions (with or without silica particles) and siloxane structures. The presence of a branched siloxane structure results in hardness and low insulating properties, while a linear siloxane structure yields softness and highly insulating properties. Both types of epoxy-based siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are considerably improved by incorporating silica particles. We expect that our developed epoxy-based composites to hold significant potential as advanced electronic packaging materials, offering high-performance and robustness.

Structural characterization of pyrolysis fuel oil (PFO) was conducted via 1H NMR and 13C NMR to elucidate its molecular structure and evaluate the feasibility of using PFO as a raw material for mesophase pitch synthesis. The average structural parameters were calculated based on the data from elemental analysis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), as well as 1H NMR and 13C NMR data. The resultant structural features of PFO were compared with those of fluidized catalytic cracking-decant oil (FCC-DO). Based on the calculated parameters, we proposed average molecular models of PFO and FCC-DO. The molecular model of PFO showed that it had an aromatic structure consisting of three aromatic rings and one naphthenic ring fused with one pericondensed and two catacondensed aromatic carbons, as well as a short alkyl side chain (with only a methyl group). This structural feature of PFO demonstrated that it is highly favorable for use as a raw material for mesophase pitch synthesis. The empirical findings in this study provide an in-depth understanding of the molecular structure of PFO as well as FCC-DO and can offer insights for future research on the utilization of PFO and other petroleum heavy oils.

Eugenol은 많은 식물에서 eugenol synthase에 의해 생합성되는 phenylpropene 계통의 휘발성 화 합물이다. 그러나, 토마토 과실에서의 특징은 밝혀져 있지 않다. 이에 따라 토마토 ‘Micro-Tom'으로 부터 RACE 기법을 이용하여 완전장 cDNA를 클로닝 하여, SlEGS라 명명하였다. SlEGS의 open reading frame은 921bp로, 307개의 아미노산 서열을 갖는 단백질로 번역되었다. BLAST 결과에 따라 SlEGS는 PhEGS1 및 CbEGS2와 각 67.1, 69.4%의 높은 상동성을 갖는 것으로 나타났다. CLC genomics workbench 프로그램을 이용하여 SlEGS의 아미노산 구성을 분석하였고, Swiss-PDB viewer 프로그램에서 homology modeling 기법으로 SlEGS의 3차원 단백질 구조를 구축한 후 ProSA-web 툴로 3차원 구조의 안정성을 확인 하였다. 또한 ExPASy의 ProtParam 툴을 이용하여 SlEGS의 생리화학적 특성을 분석 하였다. SlEGS의 추정 분자량은 33.93kDA이고 등전점(pI)은 5.85 로 산성인 것으로 나타났다. 이와 더불어 SlEGS의 흡광 계수(EC), 불안정성 지수(II), alipathic 지수 (AI), GRAVY값 등의 생리화학적 특성에 대한 분석을 실시 하였다.

The extracellular GH11 β-1,4-xylanase (XylY) gene (633-bp) of Paenibacillus sp. strain KYJ-16 was molecularly cloned by repeated DNA walking and nested PCR method. The xylY gene was predicted to encode an extracellular protein consisting of 611 amino acids with a nesuced molecular mass of 23 kDa and a calculated pI of 9.55. Protein blast search revealed that the enzyme consisted of a putative catalytic domain, which is homologous to a catalytic GH11 domain. The highest sequence identity (92%) was obtained as the catalytic GH11 domain of XylY was compared to that of Paenibacillus sp. strain HGF5 (GenBank accession number: EGG35584) that has not yet been characterized. Enzymatic properties of the recombinant His-tagged enzyme (rXylY) overexpressed in E. coli BL21 harboring pET-28a(+)/xylY will be also presented.

Two pitches with different average molecular structures were electrospun and compared in terms of the properties of their fibers after oxidative stabilization, carbonization, and activation. The precursor with a higher molecular weight and greater content of aliphatic groups (Pitch A) resulted in better solubility and spinnability compared to that with a lower molecular weight and lower aliphatic group content (Pitch B). The electrical conductivity of the carbon fiber web from Pitch A of 67 S/cm was higher than that from Pitch B of 52 S/cm. The carbon fiber web based on Pitch A was activated more readily with lower activation energy, resulting in a higher specific surface area compared to the carbon fiber based on Pitch B (Pitch A, 2053 m2/g; Pitch B, 1374 m2/g).

Presently, We have constructed an olig-d(T) primed directional cDNA library from the silkworm Dongchunghacho, an entomopathogenic fungus, of which species is belonging to Paecilomyces tenuipes Jocheon-1. To isolate and screen genes in the fungus, 626 expressed sequence tags(ESTs) were generated by a partial sequencing from the cDNA library. Paecilomyces tenuipes Jocheon-1 cDNA encoding the glyceraldehyde-3-phosphate dehydrogenase(Pt-GAPDH) of Paecilomyces tenuipes Jocheon-1 was cloned from the above cDNA library. The complete cDNA sequence of Pt-GAPDHis comprised of 1,014bp encoding 338 amino acid residues. The deduced protein sequence of Pt-GAPDH showed higher homology with Beauberia bassiana-GAPDH(93% amino acid identity). Hydropathy analysis revealed that Pt-GAPDH protein is hydrophilic. The major three amino acids in its composition of amino acid residues were alanine(11.54%), valine(9.47%) and glycine(8.88%). The cDNA encoding Pt-GAPDH was expressed as a 37 kDa polypeptide in baculovirus-infected insect Sf9 cells. The Pt-GAPDH gene of Paecilomyces tenuipes entomopathogenic fungus consisted of three exons and two introns coding for 338 amino acid residues, and the genomic DNA length of the gene spans 1302bp. The accession number of the gene in GenBank are GU997099 for Pt-GAPDH cDNA and GU997102 for Pt-GAPDH genomic DNA.

Genetic variation within and among 12 populations of whip grass in south China were investigated using inter-simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP). High genetic diversity was found in whipgrass by two molecular makers (PPB=86.21%, I=0.357 based on ISSR; PPB=82.21%, I=0.352 based on SRAP). However, there was relatively low genetic diversity at population levels. A high degree of genetic differentiation among populations was detected based on different measures and different molecular markers. We also found that SRAP markers were more efficient than ISSR markers in this species. Based on these findings, sampling strategy was proposed for successfully utilizing the genetic resource of this species.

The morecular cloning, gene structure, expression and enzyme activity of a serine-like proteas frome Laccotrephes Japonensis were examined. In this study, RT-PCR was used to amplify cDNA fragments for serine-like proteases from total RNA the hole body of Laccotrephes japonensis. The flanking sequences of the 5'- and 3'- end of the this gene were characterized by RACE-PCR. Sequence analysis showed that this gene contained an 963bp ORF encoding 321 amino acids. The deduced amino acid sequence of this protease showed 62% identity to the serine protease of Creontiades dilutus, 58% to Lygus loneolaris trypsin precuror LlsgP4, 54% to Triatonatoma infestans salivary trypsin. To generate Laccotrephes japonensis serine-like protease, the DNA fragment coding for serine protease is cloning into suttle vector pBACⅠ, named pBAC1-JG and infected to Spodoptera frugiperda (sf9) insect cell. The cDNA encoding JG was expressed as a 32-kDa polypeptide in baculovirus infected insect cells and the recombinant JG showed activity in the protease enzyme assay using gelatin as a substrate.

The subfamily Hoplolaiminae included economically important plant parasitic nematodes and consisted of more than 400 species, all having the diagnostic characters of a strongly annulated cuticle and a large stylet. Among the Hoplolaiminae genera, the genus Hoplolaimus species include species such as H. columbus, and H. galeatus that cause serious damage to crops and turf grass in the Southeastern United States. Traditional identification of species has been approached by interspecific variation of phenotypic traits that rely on morphological and morphometric characters. However, these taxonomic criteria are sometimes not practical because of their limited ability to discriminate species among closely related groups due to overlapping of important taxonomic characters. The exact species identification is needed to control target nematode and also quarantine. Therefore, genetic studies for development of molecular diagnostics, population biology, and disease management are required. In recent years, many molecular diagnostic methods have been used for the identification of plant parasitic nematodes. Advanced molecular techniques have been used that test traditional identification methods. In our studies, Hoplolaimus species showed that high genetic divergence in rDNA sequence is combined with low morphological diversity. Based on genetic information, we developed multiplex PCR for H. columbus, H. galeatus, and H. magnistylus and successfully amplified mixed populations. In molecular phylogeny, the subfamily Hoplolaiminae is an important out‐group of the Heteroderidae, a notorious plant parasite nematode group. Molecular phylogeny of the Hoplolaiminae will help us understand of pathways of pathogenesis. In our phylogenetic analysis using D2 and D3 expansion segments of 28S gene, the molecular data supported morphological based taxonomic schemes. To reconstruct more reliable phylogenetic analysis, correct assignment of each nucleotide within multiple sequence alignment is an important step. Sequence alignments based on secondary structure have been proposed as new alternative methods to obtain this goal. We predicted the secondary structure of D2 and D3 domain using computational predictions method such as the minimization energy method and comparative sequence analysis (co‐variation). Predicted secondary structure included 18 species with two outgroup species, Globodera rostochiensis, Rotylenchulus reniformis. Consensus secondary structure was obtained from closely related and distantly related species. Phylogenetically informative characters were distributed in the stem region (86.7%). These results support the effectiveness of stem and loop regions for phylogenetic analysis of the Hoplolaiminae.