• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.913-919
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• 2015

In vertebrates, the vitamin D receptor (VDR), a member of the nuclear receptor superfamily, binds the biologically active ligand $1{\alpha},25-(OH)_2$-vitamin $D_3$ (1,25 $D_3$). Nearly all vertebrates, including Agnatha, possess a VDR with high ligand selectivity for 1,25 $D_3$ and related metabolites. Although a putative ancestral VDR gene is present in the genome of the chordate invertebrate Ciona intestinalis, the functional characteristics of marine invertebrate VDR are still obscure. To elucidate the ascidian Halocynthia roretzi VDR (HrVDR), we cloned full-length HrVDR cDNA and investigated the transcriptional activity of HrVDR in HEK293 cells. HrVDR consists of 1,680 nucleotides (559 amino acids [aa]), including a short N-terminal region (A/B domain; 26 aa), DNA-binding domain (C domain; 72 aa), hinge region (D domain; 272 aa), and C-terminal ligand-binding domain (E domain; 161 aa). The amino acid sequence identity of HrVDR was greatest to that of C. intestinalis VDR (56%). In the luciferase reporter assays, the transcriptional activity of HrVDR was not significantly increased by 1,25 $D_3$, whereas the farnesoid X receptor agonist GW4064 increased the transactivation of HrVDR. These results suggest the presence of a novel ligand for and a distinct ligand-binding domain in ascidian VDR.

• Computers and Concrete
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• v.33 no.1
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• pp.77-90
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• 2024

Waste foundry sand (WFS) is the waste product that cause environmental hazards. WFS can be used as a partial replacement of cement or fine aggregates in concrete. A database comprising 234 compressive strength tests of concrete fabricated with WFS is used. To construct the machine learning-based prediction models, the water-to-cement ratio, WFS replacement percentage, WFS-to-cement content ratio, and fineness modulus of WFS were considered as the model's inputs, and the compressive strength of concrete is set as the model's output. A base extreme gradient boosting (XGBoost) model together with two hybrid XGBoost models mixed with the tunicate swarm algorithm (TSA) and the salp swarm algorithm (SSA) were applied. The role of TSA and SSA is to identify the optimum values of XGBoost hyperparameters to obtain the higher performance. The results of these hybrid techniques were compared with the results of the base XGBoost model in order to investigate and justify the implementation of optimisation algorithms. The results showed that the hybrid XGBoost models are faster and more accurate compared to the base XGBoost technique. The XGBoost-SSA model shows superior performance compared to previously published works in the literature, offering a reduced system error rate. Although the WFS-to-cement ratio is significant, the WFS replacement percentage has a smaller influence on the compressive strength of concrete. To improve the compressive strength of concrete fabricated with WFS, the simultaneous consideration of the water-to-cement ratio and fineness modulus of WFS is recommended.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.587-601
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• 2010

This review attempted to overview characteristics of nanocellulose from various sources, its isolation methods, and properties of nanocellulose-based nanocomposites. Currently, nanocelluloses could be obtained from a variety of cellulose sources, including wood pulp, tunicate, bacterial cellulose etc., and are isolated by various ways such as chemical, physical, or biological methods. The length and width of nanocellulose is in the range of 100~300 nm long and 5~50 nm wide although characteristics of nanocellulose shows a wide variability, depending on sources and isolation method. Nanocellulose is also being used as a reinforcement in the nanocomposites via various methods. Many water soluble polymers were reinforced by the incorporation of nanocellulose, which significantly improves tensile and storage moduli of the nanocomposites. In order to be used for hydrophobic polymers, the surface of nanocellulose was modified. Even though there is a significant progress in the utilization of nanocellulose as a reinforcement of polymers, further research is required to find a niche market of nanocellulose-reinforced nanocomposites. In addition, isolation methods of producing the nanocellulose in a large quantity for commercial applications should be developed to extend the application of nanocellulose-based bio-nanocomposites in future.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.295-307
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• 2006

Styela clava, called non-native tunicate or sea squirt, is habitat which include bays and harbors in Korea and several sites in the sea faced world. We fabricate cellulose membrane nerve conduit (CMNC) from this native sea squirt skin, and evaluate the capacity of promoting peripheral nerve regeneration in the rat sciatic nerve defect model. After processing the pure cellulose membrane from the sea squirt skin as we already published before, CMNC was designed as a non-tubular sheet with 14 mm length and 4 mm width. Total eleven male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into sham group (n=2), silicone tube grafted control group (n=3) and experimental group (n=6). Each CMNC grafted nerve was evaluated after 4, 8 and 12 weeks in the experimental group, and after 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were all examined using image analyzer and electromicroscopic methods in the all groups. The regenerated axon and nerve sheath were found only in the inner surface of the CMNC after 4 weeks and became more thicker after 8 and 12 weeks. In the TEM study, CMNC grafted group showed more abundant organized myelinated nerve fibers with thickened extracellular matrix than silicone conduit grafted group after 12 weeks. The sciatic function index (SFI) and ankle stance angle (ASA) in the functional evaluation were $-47.2{\pm}3.9$, $35.5^{\circ}{\pm}4.9^{\circ}$ in CMNC grafted group (n=2) and $-80.4{\pm}7.4$, $29.2^{\circ}{\pm}5.3^{\circ}$ in silicone conduit grafted group (n=3), respectively. And the myelinated axon was 41.59% in CMNC group and 9.51% in silicone conduit group to the sham group. The development of a bioactive CMNC to replace autogenous nerve grafts offers a potential and available approach to improved peripheral nerve regeneration. As we already published before, small peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx, induced the effective axonal regeneration with rapid growth of Schwann cells beneath the inner surface of CMNC. So the possibilities of clinical application as a peripheral nerve regeneration will be able to be suggested.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.922-934
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• 2000

To investigate the composition of carotenoids present in marine organisms and the biological activity of the carotenoids, carotenoids of the muscles and tunic of tunicates and shellfishes were isolated and identified. Anitmutagenic activities of the carotenoids for S. typhimurium TA 98 and cytotoxic activity for cancer cell lines were determined. Total carotenoid contents in the muscle of tunicata ranged from 18.65 mg% to 2.39 mg%. The highest amount of the total carotenoid was found in the muscle of Halocynthia aurantium, followed by Styela clava (HERDMAN), H. roretzi, H. hilgendorfi f. igaboya, H. hilgendorfi f. retteri, S. plicata (LESUEUR) in order. Interestingly, total carotenoid content in the muscle of S. clava (HERDAMAN) was higher than that of H. roretzi. Total carotenoid content of all tunicata, other than H. aurantium and H. roretzi, were higher in muscle than tunic. The major carotenoids in H. roretzi, H. aurantium, S. plicata (LESUEUR), and S. clava (HERDAMAN) were cynthiaxanthin (25.1∼42.2%), halocynthiaxanthin (9.7∼26.3%), diatoxanthin (8.0∼18.7%) and β-carotene (7.7%∼21.7%). Similarly, cantaxanthin (19.6%), cynthiaxanthin (15.4%), halocynthiaxanthin (14.8%), and (3R, 3'R), (3S, 3'S)-astaxanthin (22.6%) in H. hilgendorfi f. retteri and fucoxanthin (26.6%), cynthiaxanthin (21.8%), halocynthiaxanthin (15.2%), and β-carotene (9.3%) in H. hilgendorfi f. igaboya were major carotenoids in both tunicate. However, the composition of carotenoids in muscle and tunic of tunicata was similar each other. Among the shellfishes examined, total carotenoid content of the muscle of Peronidia venulosa (Schrenck) and Corbicula fluminea, and of the gonad of Atrina pinnata and Chlamys farreri, was ranged from 2.51 to 6.83 mg% which were relatively higher than that of other shellfishes. The composition of the carotenoids of shellfishes, which might depend upon their living environments, was varied. But cynthiaxanthin (15.9∼39.0%) and zeaxanthin (9.6∼21.9%) in gonad of C. farreri, and muscles of Buccinum Volutharpa perryi (JAY) and Crassostrea gigas, cynthiaxanthin (21.5∼48.6%) and mytiloxanthin (14.6%) in muscle of C.fluminea and gonad of A. pinnata, and canthaxanthin (60.6%) and isozeaxanthin (20.5%) in muscles of P. venulosa (Schrenck), and β-carotene (23.7%∼37.8%) and zeaxanthin (18.2∼20.4) in muscles of Semisulcospira libertina and Meretrix lusoria were major carotenoids. Interestingly, diester type-carotenoids were present along with free type-carotenoids in muscles of C. gigas. antimutagenic effect of the carotenoids isolated from tunicata and shellfishes against 2-amino-3-methylimidazol [4,5-f]quinoline (IQ) for S. typhimurium TA 98 was proportional to the amount (20, 50 and 100㎍/plate) treated. Mutagenicity of IQ was significantly reduced by astaxanthin, isozeaxanthin, mytiloxanthin and halocynthiaxanthin, whereas the mutagenicity of aflatoxin B₁(AFB₁) was significantly reduced by β-carotene, isozeaxanthin, and mytiloxnthin. Growth inhibition effect of carotenoids isolated from tunicata and shellfishes for cancer cell was proportional to the amount (5, 10, and 20㎍/plate) treated. The growth of HeLa cell by β-carotene, cynthiaxanthin, astaxanthin and halocynthiaxanthin, NCI-H87 cell by β-carotene, astaxanthin, cynthiaxanthin, and halocynthiaxanthin, HT-29 cell by β-carotene, cynthiaxanthin, mytiloxanthin and halocynthiaxanthin, and MG-63 cells by β-carotene, cynthiaxanthin, astaxanthin, canthaxanthin and halocynthiaxanthin were statistically reduced.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.227-232
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• 2006

Styela clava (also called as rough sea squirt or leathery tunicate) is regarded as native to the northwest Pacific region including Korea and widely distributed in parts of northwestern Europe, North America and Australia. To evaluate Styela clava as a potential bioactive agent, the antioxidant activity of aceton extracts from Styela clava (whole, substance and tunic) was tested by measuring inhibitory effect of $H_2O_2$ induced DNA damage using comet assay. Also, anticancer activity on human colon cancer cell (HT-29) was investigated by MTT reduction assay. The $200\;{\mu}M$ $H_2O_2$ induced DNA damage was inhibited with Styela clava aceton extract in dose dependent manner in human leukocytes. The maximum inhibition was by 62.8, 62.1 and 78.3% at the concentration of $50\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. The aceton extracts from S. clava were also found to inhibit the growth of human colon cancer cell. The cell proliferation rates decreased to 26.9, 30.6 and 12.0% at the concentration of $500\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. These results support that aceton extracts from S. clava may be a potential candidate as a possible antimutagenic and chemotherapeutic agent.