• Fisheries and Aquatic Sciences
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• 제13권3호
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• pp.206-209
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• 2010

Chum salmon (Oncorhynchus keta) meat oil contained high amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to oils extracted from other tissues of the fish. EPA and DHA occupied more than 25% of the total fatty acids in chum salmon meat oil. The main lipid classes in the meat oil were triacylglycerides and phospholipids. The major fatty acids of the molecular species composition of phosphatidylcholine isolated from the meat oil were DHA and EPA. DHA and EPA were the major molecular species in the phosphatidylcholine of chum salmon meat oil, representing 44% and 17%, respectively.

• 천문학회지
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• 제29권spc1호
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• pp.159-160
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• 1996

Recent high resolution CO observations of normal and starburst galaxies at Owens Valley Millimeter Array are summarized. While normal disk galaxies generally show exponential distribution which follows the optical blue light, starburst galaxies are often characterized by a compact ($\~$1 kpc) nuclear complex whose surface gas mass density is strongly correlated with the observed large infrared luminosity and thus the ongoing massive star formation.

• 한국대기환경학회지
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• 제27권6호
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• pp.681-691
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• 2011

The size distributions of smoke particles from fire are prerequisite for the studies on fire detection and adverse health effects. Above the flame of the fire, coagulation dominates and the smoke particles grow from 1 to 50 nm up to 100 to 3,000 nm, sizes ranging from the free-molecular regime to the continuum regime. The characteristics of the agglomeration of the smoke particles are well known, independently for each of the free-molecular and continuum regimes. However, there are not many systematic studies in the entire regime by the complexity of the mechanisms. The purpose of this work is to find the characteristics of the development of the size distribution of smoke particles by agglomeration in the entire size range covering the free-molecular regime, via transition regime, to the near-continuum and continuum regime for each variation of parameters such as fractal dimension, primary particle size and dimensionless coagulation time. In this work, the dynamic equation for the discrete-size spectrum of the particles was solved using a nodal method based on the modification of a sectional method. In the calculation, the collision frequency function for the entire regime, which is derived by using the concept of collision volume and general enhancement function, was applied. The self-preserving size distribution for the entire regime is compared with the ones for the free-molecular or continuum regimes for each variation of the parameters.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.113-113
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• 2006

Polymer separations are used to obtain information on molecular distributions (molecular-weight distribution, chemical-composition distribution, functionality-type distribution, etc.). The existing methods, such as size-exclusion chromatography are reliable, but imperfect. New methods and improvements to existing methods are being studied and some of the results will be discussed. In addition, comprehensive two-dimensional liquid chromatography allows the complete characterization of two mutually dependent distributions. LCxSEC chromatograms provide a very good qualitative impression of the distributions, but calibration is not straightforward. Finally, progress in mass spectrometry allows much better information to be obtained.

• BMB Reports
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• 제34권4호
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• pp.310-315
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• 2001

The uneven distribution of acidic and basic chitinases in different parts of rice seed, and also the characterization of hull-specific chitinases, are reported here. After extraction of chitinases from polished rice, bran, and rice hulls, the chitinases were separated into acidic and basic fractions, according to their behavior on an anion exchanger column. Both fractions from different parts of rice seed showed characteristic activity bands on SDS-PAGE that contained 0.01% glycol chitin. The basic chitinases from rice hulls were further purified using chitin affinity chromatography. The chitinase, specific to rice hulls (RHBC), was 88-fold purified with a 1.3% yield. RHBC has an apparent molecular weight of 22.2 kDa on SDS-PAGE. The optimal pH and temperature were 4.0 and $35^{\circ}C$, respectively. With [$^3H$]chitin as a substrate, RHBC has $V_{max}$ of 13.51 mg/mg protein/hr and $K_m$ of 1.36 mg/ml. This enzyme was an endochitinase devoid of ${\beta}$-1,3-glucanase, lysozyme, and chitosanase activities.

• Macromolecular Research
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• 제11권5호
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

• The Plant Pathology Journal
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• 제39권6호
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• pp.575-583
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• 2023

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.634-638
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• 2003

For the investigation of the properties of aqueous fibroin solution, the variation of molecular weight by agregation of silk, morphology and difference of molecular weight at pI value was investigated. The distribution of molecular weight investigated using gel filtration chromatography and formation of aggregates were confirmed by using Field emission scanning electron microscope. The precipitation of fibroin solution at its pI value was compared by molecular weight distribution and the formation of fibroin aggregated were investigated. The aggregation kinetics were investigated at various condition.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.471-481
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• 2017

As the molecular weight (MW) of urea-formaldehyde (UF) resins had a great impact on their properties, this work was conducted to study effect of analytical parameters of gel permeation chromatography (GPC) on the MW measurement of UF resins. GPC parameters such as flow rate, column, detector temperature, and sample injection temperature were selected to compare number-average molecular weight (Mn), weight-average molecular weight (Mw), molecular weight distribution (MWD) and polydispersity index (PDI) of two UF resins with different viscosities. As expected, UF resin with higher viscosity resulted in greater Mn and Mw than those of low viscosity UF resin. When the flow rate increased, both Mn and Mw of UF resins decreased and MWD became narrower. By contrast, both Mn and Mw increased and MWD became wide when the column, detector, and sample injection temperature increased. The column, detector, and sample injection temperature of $50^{\circ}C$ at a flow rate of $0.5m{\ell}/min$ resulted in the highest MW and broadest MWD for the GPC analysis. These results suggest that the apparent molecular size or a hydrodynamic radius of UF resin molecules dissolved in the mobile phase affect to Mn, Mw and MWD.

• 한국물환경학회지
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• 제21권2호
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• pp.125-131
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• 2005

Natural organic matter(NOM) is defined as the complex matrix of organic material and abundant in natural waters. It affects the performance of unit operations for water purification. Several kinds of analytical indicators such as DOC, specific ultraviolet absorbance(SUVA), apparent molecular weight (AMW), fractionation and high performance size exclusive chromatography(HPSEC) have been used to understand characteristics and variations of NOM. This study aims to evaluate the characteristics of NOM in the Geum River system comprising with stream flows and reservoirs. It was identified that SUVA denoting the portion of humic substance in water ranged within 1.60~3.36. Using resin adsorbents, dissolved organic carbon(DOC) was fractionated into three classes: hydrophobic bases(HOB), hydrophobic acids(HOA) and hydrophilic substances(HI). HI dominates in all samples, collectively accounting for more than 62% of the DOC. HOA was the second dominated fraction and it varied considerably but accounted for about 30% of the DOC. The distribution of high molecular weight(HMW) measured by HPSEC being used to determine the molecular weight distribution of aquatic humic substances was 40.1% and 38.7% in reservoir and stream flow, respectively. The distribution of low molecular weight(LMW) in stream flow was 13.2% higher than that in reservoir. And apparent molecular weight less than 1KDa, which include the molecular weight of hydrophilic organic matter, occupied with 69.2% and 68.2% in stream flow and reservoir, respectively. While the molecular weight of 1 to 100 KDa including humic substances ranged with 18.6% and 21.6% in stream flow and reservoir, respectively. Seasonal variation of refractory dissolved organic carbon was similar to that of SUVA.