• Smart Structures and Systems
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• v.26 no.6
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• pp.693-701
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• 2020

The conventional Kalman Filter (KF) provides a promising way for structural state estimation. However, the physical parameters of structural systems or models should be available for the estimation. Moreover, it is not applicable when the loadings applied to the structures are unknown. To circumvent the aforementioned limitations, a two-stage KF with unknown input approach is proposed for the simultaneous identification of structural parameters and unknown loadings. In stage 1, a modified observation equation is employed. The structural state vector is estimated by KF on the basis of structural parameters identified at the previous time-step. Then, the unknown input is identified by Least Squares Estimation (LSE). In stage 2, based on the concept of sensitivity matrix, the structural parameters are updated at the current time-step by using the estimated structural states obtained from stage 1. The effectiveness of the proposed approach is numerically validated via a five-story shearing model under random and earthquake excitations. Shaking table tests on a five-story structure are also employed to demonstrate the performance of the proposed approach. It is demonstrated from numerical and experimental results that the proposed approach can be used for the identification of parameters of structure and the external force applied to it with acceptable accuracy.

• Advances in concrete construction
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• v.14 no.5
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• pp.299-307
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• 2022

Cement-based matrixes have low tensile strength and negligible ductility. Adding fibres to these matrixes will improve their mechanical properties and make these composites suitable for structural applications. Post-cracking tensile strength of steel fibers-reinforced cementitious composite materials is directly related to the number of transverse fibers passing through the crack width and the pulling-out behavior of each of the fibers. Therefore, the exact recognition of the pullout behavior of single fibers is necessary to understand the uniaxial tensile and bending behavior of steel fiber-reinforced concrete. In this paper, an experimental study has been carried out on the pullout behavior of 3D (steel fibers with totally two hooks at both ends), 4D (steel fibers with a total of four hooks at both ends), and 5D (steel fibers with totally six hooks at both ends) in which the fibers have been located either perpendicular to the crack width or in an inclined manner. The pullout behavior of the mentioned steel fibers at an inclination angle of 0, 15, 30, 45, and 60 degrees and with embedded lengths of 10, 15, 20, 25, and 30 millimetres is studied in order to explore the simultaneous effect of the inclination angle of the fibers relative to the alongside loading and the embedded length of fibers on the pullout response in each case, including the maximal pullout force, the slip of the maximum point of pullout force, pullout energy, fiber rupture, and concrete matrix spalling. The results showed that the maximum pullout energy in 3D, 4D, and 5D steel fibers with different embedded lengths occurs at 0 to 30° inclination angles. In 5D fibers, maximum pullout energy occurs at a 30° angle with a 25 mm embedded length.

• Clean Technology
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• v.12 no.3
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• pp.165-170
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• 2006

When ammonia ($NH_3$) and hydrogen sulfide ($H_2S$) in binary mixture gases were supplied to a biofilter packed with biomedia made of polyurethane, PVA, and worm cast. No odor gases were detected on the outlet of the biofilter when $NH_3$ and $H_2S$ were separately supplied to the biofilter at space velocity(SV) of $50h^{-1}$ until inlet $NH_3$ concentration was increased up to 300 ppmv and inlet $H_2S$ to 428 ppmv. While, inlet $NH_3$ concentration maintained at 50 ppmv, inlet $H_2S$ concentration increased from 1 to 489 ppmv, and the removal efficiency of each gas was investigated. After that, $NH_3$ concentration increased step by step such as 80, 100, 200, 300, 400 and 500 ppmv. $H_2S$ concentration increased gradually when $NH_3$ concentration was set up at each condition. Under each condition, removal efficiency of $NH_3$ and $H_2S$ gas was investigated by analysing the gases sampled from the inlet and outlet of the biofilter. When binary gases were supplied to the biofilter and inlet $NH_3$ concentration was increased from 50 to 300 ppmv, elimination capacity of $NH_3$ increase linearly as inlet loading increased to $11.14g\;N{\cdot}m^{-3}{\cdot}h^{-1}$. However, as inlet $NH_3$ concentration increased over 300 ppmv, both removal efficiency and elimination capacity decreased while inlet loading increased. $H_2S$ removal efficiency was not affected seriously by the simultaneous supply of $NH_3$ when maximum inlet loading of $H_2S$ was under $40.27S{\cdot}m^{-3}{\cdot}h^{-1}$ and maximum inlet loading of $NH_3$ was under $15.25N{\cdot}m^{-3}{\cdot}h^{-1}$.

• Biomolecules & Therapeutics
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• v.16 no.2
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• pp.147-160
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• 2008

The present study was designed to examine effects of polyphenolic compounds isolated from red wine (PCRW) on the release of catecholamines (CA) from the isolated perfused model of the rat adrenal medulla, and to clarify its mechanism of action. PCRW (20${\sim}$180 ${\mu}$g/mL), given into an adrenal vein for 90 min, caused inhibition of the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (a direct membrane-depolarizer, 56 mM), DMPP (a selective neuronal nicotinic $N_N$ receptor agonist, 100 ${\mu}$M) and McN-A-343 (a selective muscarinic $M_1$ receptor agonist, 100 ${\mu}$M) in dose- and time-dependent fashion. PCRW itself did not affect basal CA secretion (data not shown). Following the perfusion of PCRW (60 ${\mu}$g/mL), the secretory responses of CA evoked by Bay-K-8644 (a L-type dihydropyridine $Ca^{2+}$ channel activator, 10 ${\mu}$M), cyclopiazonic acid (a cytoplasmic $Ca^{2+}$-ATPase inhibitor, 10 ${\mu}$M) and veratridine (an activator of voltage-dependent $Na^+$ channels, 10 ${\mu}$M) were also markedly blocked, respectively. Interestingly, in the simultaneous presence of PCRW (60 ${\mu}$g/mL) and L-NAME (a selective inhibitor of NO synthase, 30 ${\mu}$M), the inhibitory responses of PCRW on the CA secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclpiazonic acid were recovered to considerable level of the corresponding control release compared with those effects of PCRW-treatment alone. Practically, the amount of NO released from adrenal medulla after loading of PCRW (180 ${\mu}$g/mL) was significantly increased in comparison to the corresponding basal released level. Collectively, these results obtained here demonstrate that PCRW inhibits the CA secretory responses evoked by stimulation of cholinergic (both muscarinic and nicotinic) receptors as well as by direct membrane-depolarization from the isolated perfused adrenal gland of the normotensive rats. It seems that this inhibitory effect of PCRW is mediated by blocking the influx of both ions through $Na^+$ and $Ca^+{2$} channels into the rat adrenomedullary chromaffin cells as well as by inhibiting the release of $Ca^{2+}$ from the cytoplasmic calcium store, which are due at least partly to the increased NO production through the activation of nitric oxide synthase. Based on these data, it is also thought that PCRW may be beneficial to prevent or alleviate the cardiovascular diseases, such as hypertension and angina pectoris.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.677-685
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• 2000

Anchorage plays an important role in orthodontic treatment. Because of limited anchorage Potential and acceptance problems of intra- or extraoral anchorage aids, endosseous implants have been suggested and used. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period for osseointegration. Titanium miniscrews and microscrews were introduced as orthodontic anchorage due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and their ability to be placed in any area of the alveolar bone. In this study, a skeletal Class II Patient was treated with sliding mechanics using M.I.A.(micro-implant anchorage). The maxillary micro-implants provide anchorage for retraction of the upper anterior teeth. The mandibular micro-implants induced uprighting and intrusion of the lower molars. The upward and forward movement of the chin followed. This resulted in an increase of the SNB angle, and a decrease of the ANB angle. The micro-implants remained firm and stable throughout treatment. This new approach to the treatment of skeletal Class II malocclusion has the following characteristics . Independent of Patient cooperation. . Shorter treatment time due to the simultaneous retraction of the six anterior teeth . Early change of facial Profile motivating greater cooperation from patients These results indicate that the M.I.A. can be used as anchorage for orthodontic treatment. The use of M.I.A. with sliding mechanics in the treatment of skeletal Class II malocclusion increases the treatment simplicity and efficiency.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.581-586
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• 2017

In this study, in order to find the feasibility of thermophilic biological pre-treatment for the co-digestion of food wastewater and sewage sludge, digestion efficiency of the combined thermophilic aerobic and mesophilic anaerobic process and its effect on methane production were investigated. Also, a lab-scale co-digestion process was operated to observe parameter changes according to the increase of organic loading rates using different dilution ratios of distilled water and food wastewater (1/3 [Run I], 2/3 [Run II] in addition to using the raw food wastewater [Run III]). The results indicated that co-digestion process maintained quite stable and constant pH during entire experiments. With regard to VS removal, the higher removal was observed in the combined process and the removal efficiency was 52.24% (Run I), 66.59% (Run II) and 72.53 (Run III), respectively. In addition, the combined process showed about an 1.6-fold improved methane production rate and significantly higher methane yield than that of using single anaerobic digestion process.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.446-454
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• 2008

An advanced extraction method by ultrasonic extraction with applied solid phase extraction (SPE) has been developed for the determination of simultaneous eight major ginsenosides, namely ginsenosides Rg1, Re, Rf, Rb1, Rg2, Rc, Rb2, and Rd in the root of Panax ginseng. Four extraction methods including n-BuOH reflux extraction (Method A), 70% EtOH reflux extraction (Method B), 50% MeOH reflux extraction with SPE (Method C), and 50% MeOH ultrasonication with SPE clean-up process (Method D) were investigated for the determination of eight major ginsenosides. Total contents of ginsenosides were highest by extraction of Method C as $2.408{\pm}0.011%$. However, Method D was evaluated as relatively simpler and more efficient method due to short extraction time, small solvent consumption and less expensive, compared to conservative reflux method. Ginsenosides were also satisfactorily separated with good resolution and the accuracy range was between 1.05 and 4.06% as relative standard deviation (RSD) by Method D. SPE condition and HPLC condition were further optimized for determination of eight major ginsenosides by the ultrasonic extraction method. Conclusively, ultrasonic extraction of 2 g sample of ginseng using ultrasonic bath and 1 loading for SPE was evaluated as proper condition for extraction of ginseng.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.624-629
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• 2012

To capture and recover carbon dioxide ($CO_2$), we impregnated honeycomb made of ceramic paper with $K_2CO_3$ and its absorption characteristics of $CO_2$ were investigated. The absorption amount of $CO_2$ on the honeycomb absorbent impregnated with $K_2CO_3$ was 13.8 wt% at a constant temperature ($70^{\circ}C$) and relative humidity (66%) condition. Because the absorption amount of $CO_2$ achieved almost the same loading ratio of $K_2CO_3$ (17.6 wt%), the absorption reaction of $CO_2$ by $K_2CO_3$ on the honeycomb absorbent seems to be going smoothly. In addition, $CO_2$ absorption breakthrough characteristics of the honeycomb absorbent were analyzed at the temperature range of $50{\sim}80^{\circ}C$, and the water vapor was fed to an absorption column before the feeding of $CO_2$ or simultaneously with $CO_2$. As a result, the absorption capacity of $CO_2$ was more enhanced using the water vapor supplying before $CO_2$ than that of simultaneous supplying. It was confirmed by temperature programmed desorption analysis that the $KHCO_3$ produced by the absorption reaction of $K_2CO_3$ and $CO_2$ is regenerated by the desorption of $CO_2$ at a temperature of about $128^{\circ}C$.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.85-97
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• 2012

To investigate the usefulness of freshwater alga Water-net (Hydrodictyon reticulatum, HR) as resources for production of fermentable sugars, the easiness of enzymatic saccharification was evaluated at first. When 6 plant materials (HR, Spirulina, Chlorella, Scenedesmus, Cladophora, Corn stover) were enzymatically hydrolyzed with 2% solid loading at the same condition, HR showed the highest ratio of saccharification based on glucose production. No milled HR was also completely saccharified at the amounts of optimal enzyme mixture. Glucose yield was not changed though the citrate buffer strength for saccharification was decreased from 0.1 M to 0.1 mM. Only about 10% yield reduction was observed compared to that of $120^{\circ}C$ treatment when HR was enzymatically hydrolyzed at room temperature. The saccharification was normally occurred at $37^{\circ}C$ and pH 6.5 which is general growth condition of fermentable microrganisms, suggesting that HR have a biomass characteristics applicable for the simultaneous saccharification and fermentation. The saccharification was occurred by more than 70~80% of one of the best condition although the supplied enzyme amounts was reduced to 1/10 volume. And the glucose yield by enzymatic hydrolysis was not decreased by 10% HR solid loading and began to decrease at more than 15% solid contents. Above these results show that HR is an interesting algal biomass which is relatively easy to be saccharified by hydrolyzing enzymes. In addition, HR is a flilamentous alga and very easy to be collected. Therefore, HR seems to be an useful and valuable resources in the economical production of fermentable sugars for manufacture of bio-chemical products.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.1
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• pp.9-16
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• 2023

Liposomes as drug delivery system have proved useful carrier for various disease, including cancer. In addition, perfluorocarbon cored microbubbles are utilized in conjunction with high-intensity focused-ultrasound (HIFU) to enable simultaneous diagnosis and treatment. However, microbubbles generally exhibit lower drug loading efficiency, so the need for the development of a novel liposome-based drug delivery material that can efficiently load and deliver drugs to targeted areas via HIFU. This study aims to develop a liposome-based drug delivery material by introducing a substance that can burst liposomes using ultrasound energy and confirm the ability to target tumors using PET imaging. Liposomes (Lipo-DOX, Lipo-DOX-Au, Lipo-DOX-Au-RGD) were synthesized with gold nanoparticles using an avidin-biotin bond, and doxorubicin was mounted inside by pH gradient method. The size distribution was measured by DLS, and encapsulation efficiency of doxorubicin was analyzed by UV-vis spectrometer. The target specificity and cytotoxicity of liposomes were assessed in vitro by glioblastoma U87mg cells to HIFU treatment and analyzed using CCK-8 assay, and fluorescence microscopy at 6-hour intervals for up to 24 hours. For the in vivo study, U87mg model mouse were injected intravenously with 1.48 MBq of ⁶⁴Cu-labeled Lipo-DOX-Au and Lipo-DOX-Au-RGD, and PET images were taken at 0, 2, 4, 8, and 24 hours. As a result, the size of liposomes was 108.3 ± 5.0 nm at Lipo-DOX-Au and 94.1 ± 12.2 nm at Lipo-DOX-Au-RGD, and it was observed that doxorubicin was mounted inside the liposome up to 52%. After 6 hours of HIFU treatment, the viability of U87mg cells treated with Lipo-DOX-Au decreased by around 20% compared to Lipo-DOX, and Lipo-DOX-Au-RGD had a higher uptake rate than Lipo-DOX. In vivo study using PET images, it was confirmed that ⁶⁴Cu-Lipo-DOX-Au-RGD was taken up into the tumor immediately after injection and maintained for up to 4 hours. In this study, drugs released from liposomes-gold nanoparticles via ultrasound and RGD targeting were confirmed by non-invasive imaging. In cell-level experiments, HIFU treatment of gold nanoparticle-coupled liposomes significantly decreased tumor survival, while RGD-liposomes exhibited high tumor targeting and rapid release in vivo imaging. It is expected that the combination of these models with ultrasound is served as an effective drug delivery material with therapeutic outcomes.