• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.333-339
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• 2009

Using a novel pine needle agar, fifteen bacterial species were isolated from pine litter. These bacteria were able to degrade aromatic hydrocarbons derived from lignin and utilize the ortho-cleavage of the $\beta$-ketoadipate pathway to degrade protocatechuate or catechol. A different utilization array of aromatic hydrocarbons by these bacteria was also determined. This study provides the information on bacterial species living in pine litter and suggests that these bacteria have metabolic abilities to utilize aromatic hydrocarbons derived from lignin biodegradation.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.871-879
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• 2003

The complexation of co-contaminant mixtures between Ag(I) and polycyclic aromatic hydrocarbon (PAH) molecules (naphthalene, pyrene, and perylene) were investigated to quantify the equilibrium constants of their complexes and elucidate the interactions between Ag(I) and PAH molecules. The apparent solubilities of PAHs in aqueous solutions increased with increasing Ag(I) ion concentration. The values, K$_1$ and K$_2$ of equilibrium constants of complexes of Ag(I)-PAHs, were 2.990 and 0.378, 3.615 and 1.261, and 4.034 and 1.255, for naphthalene, pyrene, and perylene, respectively, The K$_1$and K$_2$ values of PAHs for Ag(I) increased in the order of naphthalene ＜ pyrene ＜ perylene and naphthalene ＜ pyrene ≒ perylene, respectively, indicating that a larger size of PAH molecule is likely to have more a richer concentration of electrons on the plane surfaces which can lead to stronger complexes with the Ag(I) ion. For the species of Ag(I)-PAH complexes, a 1:1 Ag(I) : the aromatic complex, AgAr$\^$＋/, was found to be a predominant species over a 2:1 Ag(I) : aromatic complex, Ag$_2$Ar$\^$＋＋/. The PAH molecules with four or more aromatic rings and/or bay regions were observed to have slightly less affinity with the Ag(I) ion than expected, which might result from inhibiting forces such as the spread of aromatic $\pi$ electrons over o wide molecular surface area and the intermolecular electronic repulsion in bay regions.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.218-224
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• 2021

This study was conducted to determine the mass-loss rates and the changes in carbon/nitrogen (C/N) ratio of dead woods, which were of following species: Dryobalanops aromatic, D. rappa, and Cratoxylum arborescens. These were dominant tree species in mixed Dipterocarp forests (MDF) and peat swamp forests (PSF) in Brunei Darussalam. In May, 2019, 48 dead wood samples (15 cm×4.8 cm×5 cm) were placed in MDF and PSF sites, and all the samples were collected after 16 months. The effects of species on mass loss were statistically significant (p<0.05); however, no difference was observed in the mass loss obtained from the two forest types (p>0.05). The initial density (g·cm^-3) of the dead woods D. aromatic, D. rappa, and C. arborescens, was 0.64±0.02, 0.60±0.00, and 0.44±0.01, respectively. Also the annual mass loss rate (%) was estimated to be 6.37, 8.17, and 18.53 for D. aromatic, D. rappa, and C. arborescens, respectively. The proportion of dead woods in decay class III was only 25% of C. arborescens samples, which were attacked by wood-feeding invertebrates, such as termites. The C/N ratio decreased significantly in D. aromatic and D. rappa, but the decreasing trend of C/N ratio was not statistically significant in C. arborescens. The results indicate that physical traits of dead woods, such as density, could be one of the main factors causing the decomposition of dead woods initially, as invertebrates such as termites are one of the key decomposers of dead wood in tropical rainforests. In the samples of C. arborescens, which was attacked by invertebrates, nitrogen immobilization occurred to lesser extent as compared to that observed in D. aromatic and D. rappa.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.106-106
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• 2003

Many polycyclic aromatic hydrocarbons (PAH) are acutely toxic to fish and other aquatic organisms in the presence of environmentally realistic intensities of solar ultraviolet radiation (SUVR). The phototoxicity of polycyclic aromatic hydrocarbons (PAHs) occurs through photodynamic activation of PAH compounds. Oxygen molecules react as quenchers with excited triplet states of PAHs producing reactive oxygen species (ROS).(omitted)

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.127-135
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• 2002

Twenty seafood samples, which are common edible species and commercially important items in Korea, were purchased at the local fisheries markets and were analyzed for polycyclic aromatic hydrocarbons (PAHs) using gas chromatography coupled to mass spectrometer detector (GC/MSD). The levels of sixteen PAHs in seafood from Korean coasts were 161 to 2,243 pg/g wet weight. The highest concentration was found at saury (Coloabis saira) and the lowest level was found at jacopever (Sebastes schlegeli). The concentrations of potentially carcinogenic PAHs of six species were in the range of 9 to 123 pg/g wet weight. The residues of PAHs in fishes from Korean coasts were slightly low or relatively moderate to other countries. There was no correlation between PAH residues and lipid contents in seafood samples. The predominant contributors in fish samples were lower-molecular-weight two and three ring aromatic PAHs such as naphthalene, acenaphthene, fluorene and phenanthrene. Filter-feeding organisms like shrimp, crab and topshell were dominated by three- and four-ring aromatic PAHs. The PAH profiles in marine sediments, bivalves, fishes, shrimp, crab and topshell according to exposure pathway were compared through factor analysis. The PAH profiles were clearly classified by the difference of species or environmental matrices. This result suggests that most of PAHs within the same samples behave identically in marine environment.

• Journal of Forest and Environmental Science
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• v.30 no.3
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• pp.253-258
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• 2014

The study attempts to assess the status, distribution, conservation and use value of Medicinal and Aromatic Plant (MAPs) in the Sagarmatha National Park. Altogether 62 species of MAPs belonging to 47 genera and 33 families have been recorded in the study area. 10 species, belonging to 9 families are categorized as the potential species. Out of the these species, most potential in local but threatened species are Allium hypsistum Stearn, Cordyceps sinensis Sacc, Dactylorhiza hatagirea Soo, Nardostachys grandiflora DC, Aconitum orochryseum, Ephedra gerardiana Wall. Ex. Stapf, Swertia multicaulis D. Don, Picrorhiza scrophulariflora Penne, Rheum australe. D. Don, Malva verticillataL and Swertia pedicallata Benerji. By analysis of data using Simpson's diversity index (SI) and Shannon weaver function (H'), there was high diversity (more heterogeneous) MAPs species composition in the Manjo Gate to Large Dobhan. (0.98349). Less diversity (less heterogeneous) MAPs species composition was in Tyanboche to Pangoche (0.90419). Similarly, the Shannon weaver function shows that in plots laying out in Mongla to Phorche are evenly distributed than others However, higher MAPs species (i.e., 31) was found in the way of Manjo Gate to Larja Dobhan than others.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.110-114
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• 2002

The repellent activity of methanol extracts from 8 aromatic medicinal plant species and a steam distillate against blood-starved Aedes aegypti (L.) females was laboratory examined by skin test and compared with that of N,N-diethyl-m-toluamide (deet). Reponeses varied according to Plant species. At a dose of $0.1mg/\textrm{cm}^2$, potent repellency against adult mosquitoes was obtained with extracts of Cinnamomum camphora (94.1 %) Cinnamomum cassia bark (91.2%), Eugenia caryophyllata flower bud (72.2%), and Tilia amurensis (69.4%). Repellent activity of these plant extracts was comparable to that of deet (83.4%). The plants described merit further study as potential mosquito-repellent agents.

• Plant Biotechnology Reports
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• v.2 no.2
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• pp.93-112
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• 2008

Medicinal and aromatic plants (MAPs) are important sources for plant secondary metabolites, which are important for human healthcare. Improvement of the yield and quality of these natural plant products through conventional breeding is still a challenge. However, recent advances in plant genomics research has generated knowledge leading to a better understanding of the complex genetics and biochemistry involved in biosynthesis of these plant secondary metabolites. This genomics research also concerned identification and isolation of genes involved in different steps of a number of metabolic pathways. Progress has also been made in the development of functional genomics resources (EST databases and micro-arrays) in several medicinal plant species, which offer new opportunities for improvement of genotypes using perfect markers or genetic transformation. This review article presents an overview of the recent developments and future possibilities in genetics and genomics of MAP species including use of transgenic approach for their improvement.

• Journal of the Korean Society of Combustion
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• v.4 no.2
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• pp.23-33
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• 1999

A turbulent non-premixed ethylene flame, which was set up in a vertical wind tunnel, was examined to understand the effect of turbulent mixing on formations of soot and gaseous species in the flames. Temperature and velocity profiles were measured using uncoated thermocouples and LDV system. Gaseous samples were withdrawn by using a water cooled stainless iso-kinetic gas sampling probe. The samples for inorganic compounds and light hydrocarbons were collected with sampling bottles and were analyzed by a gas chromatography. The samples for aromatic hydrocarbons were collected on a sorbent tube and were analyzed on a GC/MS system. Some of main results were followed. CO and $CO_2$ were measured relatively in early part of flame and the concentration of CO was greater than that of $CO_2$ all over the early flame region due to the scavenging of the oxidizing species OH by soot particles. Aromatic hydrocarbons were measured at x/D=122 along the radial direction and main important species were benzene, xylene, toluene, styrene, indene, naphthalene. The peak points of these compounds occurred at r/D=0.8 apart from the center of flame, around in which the concentration of $C_2H_2$ decayed relatively rapidly from the maximum value.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.501-508
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• 2006

The effect of chemical additives, such as dimethyl ether(DME), ethanol, carbon disulfide on the soot formation were examined numerically. ill this study, the Frenklach soot mechanism was used as a base mechanism to predict the soot formation in the ethane flame. The combination of Westbrook's DME mechanism, Marinov's ethanol mechanism, and chemical kinetic mechanism for hydrogen sulfide and carbon disulfide flames was made with the base mechanism because the DME, ethanol, $CS_2$ additives are added into the ethane fuel. CHEMKIN code was used as a numerical analysis software to simulate the effect of chemical additives on reduction of the polycyclic aromatic hydrocarbons(PAH's) which are soot precursors. From the numerical results it is observed that addition of DME, ethanol and $CS_2$ into ethane fuel can reduce PAH species significantly. That means theses additives can reduce soot formation significantly. Results also strongly suggest suppression of soot formation by these additives to be mainly a chemical effect. Hand OH radicals may be the key species to the reduction of PAH species for additives.