• Journal of Crop Science and Biotechnology
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• 제11권1호
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• pp.31-38
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• 2008

Improvement of $N_2$ fixation by symbiotic rhizobia is considered an effective means for enhancing its productivity without high input of nitrogen(N) fertilizer. Several methods to improve $N_2$ fixation have been proposed including the use of supernodulating mutants. The objective of this research was to identify the varietal difference in N and $N_2$-fixation ability among the soybean supernodulating mutants, SS2-2 and Sakukei 4, with different nodulation abilities using $^{15}N$ in field conditions in both Korea and Japan. The dry weight(DW) was higher in wild-type soybeans. The distribution rate of DW in each plant part was high in seeds of supernoduating and wild-type soybeans but high in stems and leaves of non-nodulating mutants. Although the supernodulating mutants had a low DW rate at maturity, they showed a similar $N_2$ fixation ability compared with wild-type. Supernodulating mutant plants mainly obtained N from $N_2$ fixation, while soil N was the main resource for obtaining N in non-nodulating mutants. The percentage of N derived from atmospheric dinitrogen(Ndfa) was higher in supernodulating mutants than in wild-type and relatively high in seeds between plant parts at maturity. In particular, supernodulating mutants showed higher N content in roots than those of wild-type and non-nodulating mutants. It was considered that supernodulating mutants have the advantage of saving nitrate in soil and being beneficial for N absorption of subsequent crops due to their conserving more N in the field and releasing considerable amounts of N from roots and leaves fallen to the soil.

• Journal of Korean Neurosurgical Society
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• 제61권2호
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• pp.180-185
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• 2018

Objective : Many lumbosacral fixation techniques have been described to offer a more screw-bone purchase. The forward anatomical fixation parallel to the endplate is still the most preferred method. Literature revealed little knowledge regarding the mechanical stability of lumbosacral trans-endplate fixation compared to the traditional trans-pedicular screw fixation method. The aim of this study is to assess the pull-out strength of lumbosacral screws penetrating the end plate and comparing it to the conventional trans-pedicular screw insertion method. Methods : Eight lumbar and eight sacral vertebrae, with average age 69.4 years, Left pedicles of the 5th lumbar vertebrae were used for trans-endplate screw fixation, group 1A, right pedicles were used for anatomical trans-pedicular screw fixation, group 1B. In the sacral vertebrae, the right side S1 pedicles were used for trans-endplate fixation, group 2A, left side pedicles were used for anatomical trans-pedicular screw fixation, group 2B. The biomechanical tests were performed using the axial compression testing machine. All tests were applied using 2 mm/min traction speed. Results : The average pull-out strength values of groups 1A and 1B were $403.78{\pm}11.71N$ and $306.26{\pm}17.55N$, respectively. A statistical significance was detected with p=0.012. The average pull-out strength values of groups 2A and 2B were $388.73{\pm}17.03N$ and $299.84{\pm}17.52N$, respectively. A statistical significance was detected with p=0.012. Conclusion : The trans-endplate lumbosacral fixation method is a trustable fixation method with a stronger screw-bone purchase and offer a good alternative for surgeons specially in patients with osteoporosis.

• Journal of Aquaculture
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• 제10권1호
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• pp.69-76
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• 1997

Chromatium sp., densely populated on the bacterial plate of Lake Kaiike throughout the seasons, possibly fix N2 and concurrently produce H2 N2 Fixation and H2 production by Chromatium sp. were performed under photoautotrophic growth condition, and of which rates were much higher and showed expontial growth phase. Bacterial plater samples from Lake Kaiike collected on July 27, 1994 were used to know the effect of the light or H2S on N2 fixation and H2 productin by the bacteria. At low light intensity (250 lux), low rates of N2 fixation and H2 production were detected after 18 hours. However, high rates of the production were observed under the condition of high light intensity (1000 lux). On the other hand, a very low rate of N2 fixation was observed without an addition of H2S, while the bacterial rapilly increased N2 fixation and H2 production after adding H2S and the highest rate was observed in case of adding 20mg H2S-S/$m\ell$ to the bacterial plates.

• Korean Journal of Soil Science and Fertilizer
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• 제49권1호
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• pp.17-29
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• 2016

Though there is an abundant supply of nitrogen in the atmosphere, it cannot be used directly by the biological systems since it has to be combined with the element hydrogen before their incorporation. This process of nitrogen fixation ($N_2$-fixation) may be accomplished either chemically or biologically. Between the two elements, biological nitrogen fixation (BNF) is a microbiological process that converts atmospheric di-nitrogen ($N_2$) into plant-usable form. In this review, the genetics and mechanism of nitrogen fixation including genes responsible for it, their types and role in BNF are discussed in detail. Nitrogen fixation in the different agricultural systems using different methods is discussed to understand the actual rather than the potential $N_2$-fixation procedure. The mechanism by which the diazotrophic bacteria improve plant growth apart from nitrogen fixation such as inhibition of plant ethylene synthesis, improvement of nutrient uptake, stress tolerance enhancement, solubilization of inorganic phosphate and mineralization of organic phosphate is also discussed. Role of diazotrophic bacteria in the enhancement of nitrogen fixation is also dealt with suitable examples. This mini review attempts to address the importance of diazotrophic bacteria in nitrogen fixation and plant growth improvement.

• Journal of the Korean Arthroscopy Society
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• 제2권1호
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• pp.85-92
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• 1998

Various methods for fixation of graft have been widely used for reconstruction of anterior cruciate ligament. However, the biomechanical strength of each fixation techniques are not fully understood. The purpose of this study is to compare the pull out strength of different fixation techniques which is probably the most important factor for the success at the initial stage of healing. Biomechanical test was carried out to measure and compare the pull out tensile strength of five different fixation techniques in 35 pig(Yorkshire) knees. ANOVA and Duncan multiple comparison test was applied for statistical analysis. In the two fixation techniques with bone patellar tendon bone graft, the mean maximum tensile strength was $1333.4{\pm}148.5N$ with titanium interference screw, while it was $1310.1{\pm}168.9N$ with biodegradable interference screw. The failure mode were pulled out of bone plugs from the femoral tunnel in majority cases. In the fixations with hamstring tendon, the mean maximum tensile strength were $1405.9{\pm}135.1N$ with SemiFix screw, $820.3{\pm}104.5N$ with biodegradable interference screw, and $682.1{\pm}54.2N$ with Endobutton. The mode of failure was variable in each technique. The tendon was pulled out from the tunnel in biodegradable interference screw fixation, the screw was bent in the SemiFix system, and the polyester tape were ruptured or the buttons were pulled into tunnel in Endobutton fixation. The mean maximum tensile strength of two interference screws with bone patellar tendon bone was statistically comparable to that of SemiFix with hamstring tendon. However biodegradable interference screw and Endobutton with hamstring tendon showed weaker maximum tensile strength than above three fixation techniques (P<0.05).

• Korean Journal of Microbiology
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• 제21권2호
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• pp.71-78
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• 1983

The number of aerobic free-living nitrogen fixation bacteria and factors in soil at different stands covered with Pinus rigida, Quercus acutissima and Zoysia japonica in Cheongju area were investigated from Feb. to Sept 1981. 1. The numbers of $N_2-fixation$ bacteria, according to the seasonal changes, increased gradually from winter to spring and summer. But the growth pattern revealed some differences in accordance with plant cover stands : the numbers increased abruptly in May at Pinus, May-June at Quercus and Apr. May at Zoysia stand. The pick of numbers represented in Aug. Sept, at Pinus, Jul-Aug. at Quercus and May-Jun. at Zoysia stand, respectively. 2. The interrelationship between the monthly changes of enviotnmental factors and numbers of $N_2-fixation$ bacteria at different stands, mainly depends upon the soil temperature than other soil factors (r=0.71-0.84). The numbers of $N_2-fixation$ bacteria may increase 5-7 times according to increase $10^{\circ}C$ of soil temperature, and optimal range was $20{\sim}30^{\circ}C$ for growth. Equation of the interrelation between soil temperature and numbers could be stated as follows : log y=ax+b. 3. In the case of high soil temperature, the bacterial numbers presented high level in drought periods. Therefore, the $N_2-fixation$ bacterial species in these soil seem to consist of resistant to desication. 4. The influence of soil organic matter for growth of $N_2-fixation$ bacteria indicated low conrelation. The reason may seen the content of organic matter in these soil existed abundantly above the quantities of limitation for growth. 5. In artifical gradients, the $N_2-fixation$ bacteria were predominated at $20{\sim}30^{\circ}C$ same as natural condition, pH7-8, and 20-30% of soil water contents. 6. The vertical distribution of bacteria marked decreasing trends from surface to lower layers, and the decreasing degree was shown well in Zoysia, Quercus and Pinus stand in order. But in the trees, the numbers increased at 30cm layer estimated the region of root than 20cm layer. 7. Both catalase megative and positive group of $N_2-fixation$ bacteria in soil increased according to the rise of the soil temperature. Catalase positive group was revealed as dominant group in winter, and catalase negative group revealed in summer. The change of dominant pattern was shown during Feb. to Apr.

• Journal of Veterinary Clinics
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• 제37권3호
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• pp.115-122
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• 2020

The aim of this study was to evaluate double-pigtail ureteral stent fixation in cats. Medical records of 19 cats (23 ureters) with complete ureteral obstruction that double-pigtail ureteral stent placement were carried out were retrospectively reviewed. The cats were randomly classified into two groups; 13 cats (16 ureters) with double-pigtail ureteral stent fixed to urinary bladder (SF group) and 6 cats (7 ureters) with not fixed to urinary bladder (SNF group). The average age and weight of the cats was 7.4 years and 3.73 kg, respectively. Postoperative complications included chronic renal failure (n = 11), lower urinary track diseases (cystitis, hematuria, pollakiuria) (n = 7), stent migration (n = 6), anemia (n = 5), ascites (n = 2), hyperthermia (n = 1), enteritis (n = 1), oliguria (n = 1), hypotension (n = 1), ureteritis (n = 1), and pyelonephritis (n = 1). Stent migration did not occur in the 16 ureters of the cats in SF group but did occur in 4 out of 7 ureters of the cats in SNF group. The prevention of stent migration by stent fixation was significant (P = 0.04). Among the 13 cats in SF group, only 2 cats developed lower urinary track diseases, while 4 of the 6 cats in SNF group showed symptoms of lower urinary track disease. Thus, the cats that underwent double-pigtail ureteral stent fixation to the urinary bladder developed significantly fewer lower urinary diseases (P = 0.046). In conclusion, double-pigtail ureteral stent fixation to the urinary bladder for treatment of complete ureteral obstruction in cats can effectively prevent stent migration, which is common complication of stent placement.

• Korean Journal of Organic Agriculture
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• 제19권spc호
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• pp.161-164
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• 2011

Nitrogen fixation by legumes can be valuable sources for organic farming. This study was to investigate the effect of different legume mixtures on nitrogen fixation and transfer to grasses on spring paddy field. Three different mixtures were used (rye+hairy vetch, Italian ryegrass+crimson clover, oat+pea) in a randomized complete block design with three replications and sowed in pots with different sowing rate (5:5 rye:hairy vetch,7:3=Italian:crimson, 6:4=oat:pea) on early March. $(^{15}NH_4)SO_4$ solution at. 99.8 atom%$^{15}N$ was applied to the each pot at the rate of 2kg N $ha^{-1}$ on $16^{th}$ April. Forage were harvested at ground level in heading stage and separated into legume and grass. Total N content and $^{15}N$ value were determined using a continuous flow stable isotope ratio mass spectrometry. DM yield of rye+vetch, Italian+crimson and oat+pea were 6,607, 3,213 and 4,312kg/ha, respectively. Proportion of N from fixation was 0.73(rye+vetch), 0.42(Italian+crimson) and 0.93(oat+pea). The percentages of N transfer from legume to grass were from 61% to 24% in different method by treatments and -35% to 21% in isotope dilution method.

• Mass Spectrometry Letters
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• 제13권2호
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• pp.35-40
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• 2022

Human tissues and organs can be preserved intact by fixation with formalin for the future analysis of biomolecules of interest. With the advances in high-throughput methods, numerous protocols have been developed and optimized to attain the most pathophysiological information out of biomolecules, including RNA and proteins, in formalin-fixed samples. However, there is no systematic study to examine the effects of formalin fixation on the lipidome of biological samples in a global fashion. In this study, we conducted a mass spectrometry-based analysis to survey the alteration in the lipidome of mice brains by fixation methods. A total of 308 lipids were quantitatively measured using triple quadrupole mass spectrometry. We found that most were unchanged after formalin fixation except for a few lipid classes such as phosphatidylethanolamine.

• Journal of Trauma and Injury
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• 제28권2호
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• pp.55-59
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• 2015

Purpose: To compare clinical and radiographic outcomes of between two and three Kirschner wire(K-wire) intramedullary fixation for fractures in the neck of the metacarpal bone. Methods: A single institutional retrospective review identified 28 cases of metacarpal fractures between March 2010 and August 2014. Each of the cases met the inclusion criteria for closed, extra-articular fractures of the neck of the metacarpal bone. The patient groups were divided by the number of K-wire. Outcomes were compared for range of motion of the metacarpophalangeal joint, radiographic parameters, and period until union. Results: The fractures were treated with either 2 Kirschner wire fixation (n=10) or 3 Kirschner wire fixation (n=18). The active range of motion of metacarpophalangeal joint and radiographic result showed no statistically significant difference between the two groups. The mean union period was 5.9 weeks. However, four cases suffered distal head perforation in 2 K-wire fixation group and one case in 3 K-wire fixation group. Conclusion: Multiple retrograde intramedullary Kirschner wire fixation is a good treatment of choice for fractures in the neck of the metacarpal bone. To prevent metacarpal head perforation, it is preferred to use three K-wires than two K-wires.