• Title/Summary/Keyword: n'-site

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Changing C-N Interactions in the Forest Floor under Chronic N Deposition: Implications for Forest C Sequestration

  • Park, Ji-Hyung
    • Journal of Ecology and Environment
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    • v.31 no.3
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    • pp.167-176
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    • 2008
  • Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

Reducing the donor site morbidity in radial forearm free flaps by utilizing a narrow radial forearm free flap

  • Shaikh, Safdar Ali;Bawa, Amber;Shahzad, Noman;Yousufzai, Zara;Ghani, Muhammad Shahab
    • Archives of Plastic Surgery
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    • v.45 no.4
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    • pp.345-350
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    • 2018
  • Background The radial forearm free flap (RFFF) has remained a leading choice of many plastic surgeons as a fasciocutaneous flap due to its versatility, pedicle length, and simple elevation technique. However, donor site morbidity has led many reconstructive surgeons to limit their use of the RFFF and to use other flaps instead. We propose that using a narrow RFFF (nRFFF) decreases the aesthetic and functional morbidity of the donor site. Methods We report our experiences with the nRFFF from April 2012 through May 2015 at the Department of Plastic, Reconstructive, and Hand Surgery at Liaquat National Hospital, Karachi. The donor defects were closed primarily. The Stony Brook Scar Evaluation Scale and comparison with the contralateral hand were used to assess aesthetic and functional outcomes, respectively. Results A total of 24 patients underwent nRFFF procedures during the study period. The donor arm showed excellent motor function in 22 cases (91.7%), and very good function in the remaining two cases (8.3%). The aesthetic outcomes were excellent in four patients (16.6%), very good in eight patients (33.3%), good in 10 patients (41.6%), and fair in two patients (8.3%) who developed a hypertrophic scar. All flaps were successful and there were no cases of partial or complete loss. Conclusions For small to medium-sized soft tissue defects, the nRFFF had acceptable outcomes due to its thinness, pliability, and major reduction in donor site aesthetic and functional morbidity.

Quantitative Structure-Activity Relationships in MAO-Inhibitor~' 2-Phenylcyclopropylarnines: Insights into the Topography of MAO-A and MAO-B

  • Kang, Gun-Il;Hong, Suk-Kil
    • Archives of Pharmacal Research
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    • v.13 no.1
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    • pp.82-96
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    • 1990
  • Ten (E)-and (Z)-isomers of 2-phenylcyclopropylamine (PCA), 1-Me PCA, 2-Me-PCA, N-Me-PCA, and N, N-diMe PCA and fifteen o-. m-, p- isomers of (E) PCA with substituents of Me, Cl, F, OMe, OH were synthesized in this laboratory and tested for the inhibition of rat brain mitochondrial MAO-A and MAO-B. The effects of substituents, their positions, and stereochemistry on the inhibition were assessed for the compounds with substituents at cyclopropyl and amino groups and QSAR analyses were performed using the potency data of ring-substituted compounds. The best correlated QSAR equations are as follows : pI$_{50}$ = 0.804 $\pi^2$-0.834 Blo-1.069 Blm + 0.334 Lp-1.709 HDp +7.897 (r = 0.945, s =0.211, F = 16.691, p = 0.000) for the inhibition of MAO-A;PI$_{50}$= 1.815$\pi$-0.825 $\pi^2$-1.203R + 0.900 Es$^2$ + 0.869 Es$^3$ + 0.796 Es$^4$-0.992 HDp + 0.562 HAo + 3.893 (r = 0.982, s =0.178, F = 23.351, p = 0.000) for the inhibition of MAO-B. Based on the potency difference between stereoisomers of cyclopropylamine-modified compounds and an QSAR cavity near para position, two hydrophobic carities interacting with Me group, a hydrophobic site near para position, and an amino group binding site and that in addition to the same two hydrophotic cavities, hydrophotic area, steric boundaries, hydrogen-acceptor site, and amino group binding site, another steric boundary near para position and a hydrogen donating site near ortho position constitute active sites of MAO-B.

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Plant Settlement Patterns and Their Effects on Breeding Sites of Little Terns (Sterna albifrons) on Sand Bars on Ganwol Lake

  • Nam, Jong-Min;Yoon, Ji-Hyun;Kim, Heung-Tae;Kim, Jae-Geun
    • Journal of Ecology and Environment
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    • v.31 no.1
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    • pp.37-43
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    • 2008
  • We analyzed soil characteristics, soil seed banks, and plant communities in a small islet in Ganwol Lake from May 2005 to August 2006 to examine the forces driving plant settlement on sand bars and the effects of plant settlement patterns on nesting sites of little terns (Sterna albifrons). The soil nutrients contents in a site where the feces of wintering birds accumulate (N: 15.4 mg/kg, P: 10.5 mg/kg, LOI: 0.51 %, pH: 6.8) and a site where organic sediments accumulate (N: 20.7 mg/kg, P: 16.4 mg/kg, LOI: 0.40%, pH: 6.6) were much higher those of a control site which was not affected by bird feces and organic sediments (N: 4.1 mg/kg, P: 5.4 mg/kg, LOI: 0.41%, pH: 6.7). However, a seed bank was formed only on the site with accumulated organic sediments. Plant settlement was accelerated by feces from wintering birds and organic sediment accumulation on sand bars in Ganwol Lake. The percentage of area disturbed by human activities increased from 0.2% in May 2005 to 13.9% in August 2006, and the percentage of annual communities increased from 27.5% to 43.3%, but the percentage of open area decreased from 55.2% to 28.0% from May 2005 to August 2006. These increases in disturbed area and annual communities decreased the open area for breeding of little terns. The enlargement of P. communis and T. angustata communities was suppressed by irregular flooding. These results provide useful information for the management of little tern breeding sites for conservation purposes.

Reconstruction of hand using anterolateral thigh fascial free flap (전외측대퇴근막 유리피판술을 이용한 수부의 재건)

  • Kim, Ki Wan;Kim, Jin Soo;Lee, Dong Chul;Ki, Sae Hwi;Roh, Si Young;Yang, Jae Won
    • Archives of Plastic Surgery
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    • v.36 no.5
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    • pp.571-577
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    • 2009
  • Purpose: The Provision of thin and pliable tissue and the adequate coverage of tendon - gliding surface is necessary for a soft tissue defect of the hand with exposure of bone, tendon and muscle. This report will discuss our experience with anterolateral thigh fascial free flap for the reconstruction of the soft tissue defect of the hand. Methods: Between February 2004 and August 2008, seven patients with full - thickness soft tissue defects of the hand were reconstructed by means of a composite anterolateral thigh fascial free flap. There were soft tissue defects associated with trauma (n=5), scar contracture (n=1) and necrosis due to ischemia (n=1). Flaps were harvested from the anterolateral thigh as adipofascial flaps with only a small sheet of fascia and fatty tissue above it. The fascia and the skin of the donor site was closed directly and delayed split - thickness skin graft was performed. Result: All flaps survived completely. The size of the transferred flap ranged from $2{\times}4cm$ to $5{\times}8cm$. Thin flap coverage was possible without secondary debulking operations. It left minimal donor site morbidity with a linear scar. In one case, the thigh muscle herniation in the donor site was developed. Conclusion: The anterolateral thigh fascial free flap provided thin and pliable tissue which can establish a tendon - gliding mechanism, minimal bulk, minimal donor site morbidity. The disadvantages of this technique were the need for a skin graft and the muscle herniation of donor site.

Single-crystal Structure of Fully Dehydrated and Largely NH4+-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH4)60Na11│[Si121Al71O384]-FAU

  • Seo, Sung-Man;Kim, Ghyung-Hwa;Kim, Young-Hun;Wang, Lian-Zhou;Lu, Gao-Qing;Lim, Woo-Taik
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.543-550
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    • 2009
  • The single-crystal structure of largely ammonium-exchanged zeolite Y dehydrated at room temperature (293 K) and 1 ${\times}\;10^{-6}$ Torr. has been determined using synchrotron X-radiation in the cubic space group $Fd\overline{3}m\;(a=24.9639(2)\AA)$ at 294 K. The structure was refined to the final error index $R_1$ = 0.0429 with 926 reflections where $F_o>4\sigma(F_o)$; the composition (best integers) was identified as |$(NH_4)_{60}Na_{11}$|[$Si_{121}Al_{71}O_{384}$]-FAU. The 11 $Na^{+}$ ions per unit cell were found at three different crystallographic sites and 60 ${NH_4}^{+}$ ions were distributed over three sites. The 3 $Na^{+}$ ions were located at site I, the center of the hexagonal prism ($Na-O\;=\;2.842(5)\;\AA\;and\;O-Na-O\;=\;85.98(12)^{\circ}$). The 4 $Na^{+}$ and 22 ${NH_4}^{+}$ ions were found at site I' in the sodalite cavity opposite the double 6-rings, respectively ($Na-O\;=\;2.53(13)\;\AA,\;O-Na-O\;=\;99.9(7)^{\circ},\;N-O\;=\;2.762(11)\;\AA,\;and\;O-N-O =\;89.1(5)^{\circ}$). About 4 $Na^{+}$ ions occupied site II ($(Na-O\;=\;2.40(4)\;\AA\;and\;O-Na-O\;=\;108.9(3)^{\circ}$) and 29 ${NH_4}^{+}$ ions occupy site II ($N-O\;=\;2.824(9)\;\AA\;and\;O-N-O\;=\;87.3(3)^{\circ}$) opposite to the single 6-rings in the supercage. The remaining 9 ${NH_4}^{+}$ ions were distributed over site III' ($N-O\;=\;2.55(3),\;2.725(13)\;\AA\;and\;O-N-O\;=\;94.1(13),\;62.16(15),\;155.7(14)^{\circ}$).

On the Study of Blasting Vibration, Sound by Measuring Gage Influence to Exist Crack in 154kV Daeshin Electric Cable Tunnel (154kV 대신 S/S인출 전력구 시험발파 패턴 및 진동, 소음 계측에 의한 기존 CRACK에 미치는 영향 연구)

  • 강대우;박태원
    • Explosives and Blasting
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    • v.16 no.3
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    • pp.25-34
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    • 1998
  • This area is covered in Andesite of high compression strength and located in PUSAN SEO-KU. There are many old houses around shaft site. So, we must have a cautious blasting operation. A total of 40 blasts were test at DAE-SHIN Shaft site to study the magnitude and frequency characterization of blast-induced vibration. The effect of viblating frequency on structual damage and site-specific scaling to define th empirical equations were also discussed. The result can be summarized as follows: 1. Some empirical equations were obtained. $V=K\{{\frac{D}{W}}1/3\}^{-n}$ where the values for n and K are estimated to be -1.407 to -2.202 and 643.3489 to 7283.2104 respectively. 2. Dominant frequencies at short distance are in the range of about 75.0 to 91.8 Hz, with some exceptions of about 50Hz, Frequencies observed at long distance are in the range of 10 to 2Hz. It is apparent the shift of dominant frequency down to lower levels at long distance.

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Solubilization of an Angiotensin II Binding Site from Rat Liver

  • Chung, Sung-Hyun;Ravi Iyengar
    • Archives of Pharmacal Research
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    • v.14 no.3
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    • pp.231-236
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    • 1991
  • The high affinity binding sites for angiotensin II were solubilized from rat liver membranes by treatment with CHAPS. The binding protein was also partially purified by angiotensin III inhibitor-coupled Affi-gel affinity chromatography. Binding to the intact membrances as well as to the solubilized preparation was specific and saturable. According to the Scatchard plot, the membrane preparations exhibited a single class of high affinity binding sites with a Kd OF 0.71 nM. The solubilized preparation also showed the presence of a single class of bindings sites with less affinity (Kd of 14 nM). Meanwhile the competition studies using angiotensin II analogues represented two separate binding sites for angiotensin II and single binding site for antagonist. These latter findings were correlated to the results provided by Garrison's research group. More works are needed to clarify this discrepancy.

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KNOTTED AND LINKED PRODUCTS OF RECOMBINATION ON T (2, n)#T (2, m) SUBSTRATES

  • Flapan, Erica;Grevet, Jeremy;Li, Qi;Sun, Chen Daisy;Wong, Helen
    • Journal of the Korean Mathematical Society
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    • v.51 no.4
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    • pp.817-836
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    • 2014
  • We develop a topological model of site-specific recombination that applies to substrates which are the connected sum of two torus links of the form T(2, n)#T(2, m). Then we use our model to prove that all knots and links that can be produced by site-specific recombination on such substrates are contained in one of two families, which we illustrate.

Changes of Nitrifying Bacteria Depending on the Presence and Absence of Organic Pollutant in Nak-Dong River (낙동강에서의 유기성 오염 유무에 따른 질화세균의 변화)

  • Jin, Seon-Yeong;Lee, Young-Ok
    • Korean Journal of Microbiology
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    • v.49 no.2
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    • pp.137-145
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    • 2013
  • This study was performed at 2 sites of Nak-Dong River to investigate the changes of nitrifiers depending on the presence and absence of organic pollutants (due to the effluents of domestic wastewater treatment plant, WWTP). Conventional chemical parameters such as T-N, $NH_4$-N, $NO_2$-N, $NO_3$-N were measured and the quantitative nitrifiers at the 2 sites were analyzed comparatively by fluorescent in situ hybridization (FISH) with NSO190 and NIT3, after checking the presence of gene amoA of ammonia oxidizing bacteria (AOB) and 16S rDNA signature sequence for Nitrobacter sp. that belongs to nitrite oxidizing bacteria (NOB). Also ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria were detected using FISH to get a glimpse of the general bacterial community structure of the sites. Based on the distribution structure of the ${\alpha}{\cdot}{\beta}{\cdot}{\gamma}$-Proteobacteria and the measurement of nitrogen in different phases, it could be said that the site 2 was more polluted with organics than site 1. Corresponding to the above conclusion, the average numbers of AOB and NOB detected by NSO160 and NIT3, respectively, at site 2 [AOB, $9.3{\times}10^5$; NOB, $1.6{\times}10^6$ (cells/ml)] was more than those at site 1 [AOB, $7.8{\times}10^5$; NOB, $0.8{\times}10^6$ (cells/ml)] and also their ratios to total counts were higher at site 2 (AOB, 27%; NOB, 34%) than those at site 1 (AOB, 18%; NOB, 23%). Thus, it could be concluded that the nitrification at site 2 was more active due to continuous loading of organics from the effluents of domestic WWTP, compared to site 1 located closed to raw drinking water supply and subsequently less polluted with organics.