• Molecules and Cells
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• v.40 no.2
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• pp.143-150
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• 2017

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

• Lettere Italiane
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• no.36
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• pp.125-150
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• 2012

Vittorio Alfieri fu celebrato dagli uomini del Risorgimento come "l'iniziatore ed il padre della rinascita" e il creatore della coscienza nazionale. Per questo è lodato da Foscolo, Manzoni, Leopardi, Mazzini, Gioberti, Oriani, Carducci. Ma insieme con i suoi meriti politici, anche i valori artistici delle sue opere non debbono essere dimenticati. Anche sul pensiero e sull'opera dell'Alfieri influirono le ideologie tipiche del secondo Settecento, l'Illuminismo e il nascente Romanticismo, in lui intrecciandosi e scontrandosi ad un tempo. Il suo interesse per lo studio dell'uomo, per la concezione meccanicistica del mondo, la lontananza dalla religione per l'assoluta libertà e l'avversione verso il dispotismo, collegano Alfieri alla dottrina illuminista. I temi letterari illuministici, volti a chiarificare le coscienze e ad apportare il progresso sociale e civile, sono affrontati dal poeta non in modo distaccato, ma con l'emotività e le inquietudini del pensiero romantico. Ma i letterati romantici dell'Ottocento furono piuttosto ostili all'opera dell'Alfieri, accusandola di astratezza, di lontananza dagli interessi e dalla realtà della vita moderna e di assenza di senso storico. Invece nei primi anni del Novecento, Croce lo presenta come iniziatore della nuova letteratura italiana, con la quale egli avrebbe in comune l'individualismo, la passionalità, l'amore per la solitudine, la malinconia. Anche se gli manca l'ansia religiosa sul fine e il valore della vita e l'interessamento per la storia, ecc., secondo il Croce si può definire un protoromantico. Nelle sue opere ci sono, sotto l'aspetto dell'Illuminismo l'odio istintivo contro la tirannide e l'amore per la libertà, e sotto quello protoromantico esplode l'urto violento di sentimenti e passioni e l'esaltazione della morte eroica dei protagonisti. E anche Saul e Mirra descrivono l'idea dell'umanità eroica che muore dopo una lunga vicenda di miseria e di abbiezione. L'idea dell'umanità nuova in Saul e Mirra è l'idea degli uomini nuovi che egli desiderava.

• Computers and Concrete
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• v.19 no.1
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• pp.59-68
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• 2017

This study focused on modeling the behavior of the compressive stress using the average strain and ultrasonic test results in concrete. Feed-forward backpropagation artificial neural network (ANN) models were used to compare four types of concrete mixtures with varying water cement ratio (WC), ordinary concrete (ORC) and concrete with short steel fiber-reinforcement (FRC). Sixteen (16) $150mm{\times}150mm{\times}150mm$ concrete cubes were used; each contained eighteen (18) data sets. Ultrasonic test with pitch-catch configuration was conducted at each loading state to record linear and nonlinear test response with multiple step loads. Statistical Spearman's rank correlation was used to reduce the input parameters. Different types of concrete produced similar top five input parameters that had high correlation to compressive stress: average strain (${\varepsilon}$), fundamental harmonic amplitude (A1), $2^{nd}$ harmonic amplitude (A2), $3^{rd}$ harmonic amplitude (A3), and peak to peak amplitude (PPA). Twenty-eight ANN models were trained, validated and tested. A model was chosen for each WC with the highest Pearson correlation coefficient (R) in testing, and the soundness of the behavior for the input parameters in relation to the compressive stress. The ANN model showed increasing WC produced delayed response to stress at initial stages, abruptly responding after 40%. This was due to the presence of more voids for high water cement ratio that activated Contact Acoustic Nonlinearity (CAN) at the latter stage of the loading path. FRC showed slow response to stress than ORC, indicating the resistance of short steel fiber that delayed stress increase against the loading path.

• Journal of the Korean Society of Radiology
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• v.9 no.5
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• pp.295-300
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• 2015

There are various type of particle accelerators such as Kyoungju 100-MeV proton beam accelerator in Korea. And Korea plans to build large particle accelerator such as heavy ion accelerator and 4th generation light source facility. The accelerated high energy particles of these facility produce 2nd neutron after nuclear reaction with target materials. And then these 2nd neutron activate structural materials and surrounding environment. Accordingly, it is important to consider the activation and shielding calculation on design of facility for safety operation. In this study, we tried to calculate and compare the neutron flux from the interaction $^{la}150$ beam with target material(Cu) according to thickness of iron and concrete shielding material by MCNPX 2.7 with nuclear library JENDL/HE 07and la150. To verify the properties of nuclear library, we compared computational results with experimental value. These results can be used for dose evaluation technology in planning of the shielding of large particle accelerator.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.68-73
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• 2002

The dielectric properties and synthesis of $LaAlO_3$ ceramics from mixtures of $La_2O_3-Al_2O_3$ (LAO) and $La_2O_3-Al(OH)_3$(LAH) via grinding process were investigated. The single phase $LaA1O_3$of LAO and LAH powders were formed at $1300^{\circ}C$ and $1000^{\circ}C$, respectively. A non-reacted $La_2O_3$ existing in calcined powder was changed to La(OH)$_3$by moisture in the air, and their samples were worse than those of the samples made from a $LaA1O_3$single phase powder. The densities of LAO samples sintered at 150$0^{\circ}C$ for 4 h and LAH samples sintered at $1400^{\circ}C$ for 4 h were 97.3% and 98.3% of theory density, respectively. Grains of LAH sample showed uniformity and their sizes were 0.75 ${\mu}{\textrm}{m}$, and LAO samples showed non-uniformity and their sizes were 4-5 ${\mu}{\textrm}{m}$. Dielectric constant of LAO and LAH samples were the same value (≒22), however dielectric loss of LAH sample (0.0003) were lower than that of LAO sample(0.001)due to grain size.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.29-37
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• 1999

In this study, we have prepared PLT thin films having various La concentrations by using sol-gel method and studied on the effect of La concentration on the electrical properties of PLT thin films. As the La concentration increases from 5mol% to 28mol%, the dielectric constant at 10kHz increases from 428 to 761, while the loss tangent decreases from 0.063 to 0.024. Also, the leakage current density at 150kV/cm has a tendency to decrease from 6.96${\mu}A/cm^2$ to 0.79${\mu}A/cm^2$. In the result of hysteresis loops of PLT thin films, the remanent polariation and the coercive field decrease from 9.55${\mu}C/cm^2$ to 1.10${\mu}C/cm^2$ and from 46.4kV/cm to 13.7kV/cm, respectively. With the result of the fatigue test on the PLT thin films, we have found that the fatigue properties are improved remarkably as the La concentration increases from 5 mol% to 28mol%. In particular, the PLT28) has paraelectric phase and its charge storage clensity and leakage current density at 5V are 134fC/${\mu}cm^2$ and 1.01${\mu}A/cm^2$, respectively. The remanent polarization and coercive field of the PLT(10) film are 6.96${\mu}C/cm^2$ and 40.2kV/cm, respectively. After applying of $10^9$ square pulses with ${\pm}5V$, the remanent polarilzation of the PLT(10) film decreases about 20% from the initial state. In the results, we conclude that the 10mol% and the 28mol% La doped PLT thin films are very suitable for the capacitor dielectrics of new generation of DRAM and NVFRAM respecitively.

• Polymer(Korea)
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• v.33 no.3
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• pp.213-218
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• 2009

A cationic lipid emulsion containing 1,2-dioleoyl-3-trimethylammonium-propane(DOTAP), Tween80, squalene has been prepared as a gene delivery system. In order to increase the transfection efficiency of gene carrier, folate was used as the tumor-targeting ligand that was attached on PEG-DPPE. HeLa and 293 cells were used for the in vitro transfection experiment. HeLa cell is a folate-positive cell line. The mean particle sizes of polymeric lipid system and DNA/lipid complex system were 206.6 nm and 150.5 nm, respectively. The transfection efficiencies of our carriers(4:l(w:w) complex ratio)were 100 times higher than that of DOTAP only emulsion due to the targeting effect of folate.

• Korean Journal of Materials Research
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• v.19 no.4
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• pp.186-191
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• 2009

Thermoelectric power and resistivity are measured for the perovskite $LaNi_{1-x}Ti_xO_3$ ($x{\leq}0.5$) in the temperature range 77 K - 300 K. The measured thermoelectric power of $LaNi_{1-x}Ti_xO_3$ ($x{\leq}0.5$) increases linearly with temperature and is represented by A + BT. The x = 0.1 sample showed metallic behavior, the x = 0.3 showed metal and insulating transition around 150 K, and x = 0.5 showed insulating behavior the over the whole temperature range. The electrical resistivity of x = 0.1 shows linear temperature dependence over the whole temperature range and $T^2$ dependence. On the other hand, the electrical resistivity of x = 0.3 shows a linear relation between $ln{\rho}$ and $T^{-1/4}$ (variable range hopping mechanism) in the range of 77 K to 150 K. For x = 0.5, the temperature dependence of resistivity is characteristic of insulating materials; the resistivity data was fitted to an exponential law, such as ln(${\rho}/T$) and $T^{-1}$, which is usually attributed to a small polaron hopping mechanism. These experimental results are interpreted in terms of the spin polaron (x = 0.1) and variable range hopping (x = 0.3) or small polaron hopping (x = 0.5) of an almost localized $Ni^{3+}$ 3d polaron.

• Journal of Environmental Science International
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• v.29 no.5
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• pp.435-443
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• 2020

The purpose of this study was to investigate eco-friendly measures to manage major diseases which cause heavy economic damages to ginseng. Morphological, physicochemical, and molecular biological species identification was carried out after isolating useful antagonistic bacteria from ginseng fields. In addition, optimal conditions for mass culture were established, and he efficacy of the bacteria in the prevention of the diseases was verified in the field. The results showed that about 150 bacteria were extracted from 150 ginseng fields in the whole county. Among them, B. pyrrocinia LA101 was finally selected, which had a strong antagonistic potency against Alternaria panax, Botrytis cinerea, Rhizoctonia solani, and Cylindrocarpon destructans on agar media. The B. pyrrocinia LA101 is a baculiform gram-negative bacterium identified as Burkholderia pyrrocinia according to results from an API(Analytical Profile Index) kit, 16S rRNA, and gyrase gene sequencing analysis. It was donated to the microbe bank of the Agricultural Genetic Resources Center at the National Academy of Agriculture Science under the Rural Development Administration on September 28, 2011 (Donation No. KACC91663P). A patent for the mass culture technology was granted in August 2012 (Patent No. 10-1175532).

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.150-152
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• 2005

$La_{0.2}Ca_{0.8}MnO_3$ colossal magnetoresistance (CMR) powders and pellets were synthesized by sol-gel process involving a stable metal chelate complex with acetylacetone. The structural changes of reaction mixture were monitored by FT-IR spectroscopy and X-ray diffractometry. The microstructure of sintered samples and the cation composition of gel powder were studied by FE-SEM/EDS and ICP-AES. The magnetic property was investigated as a function of temperature.