• Title/Summary/Keyword: Curing effect

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EFFECT OF INTERMITTENT POLYMERIZATION ON THE RATE OF POLYMERIZATION SHRINKAGE AND CUSPAL DEFLECTION IN COMPOSITE RESIN (복합 레진의 간헐적 광중합 방법이 중합 수축 속도와 치아의 교두 변위에 미치는 영향)

  • Kim, Min-Kyung;Park, Sung-Ho;Seo, Deog-Gyu;Song, Yun-Jung;Lee, Yoon;Lee, Chan-Young
    • Restorative Dentistry and Endodontics
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    • v.33 no.4
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    • pp.341-351
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    • 2008
  • This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins. The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & 1s with light off for 90s): Group 3) intermittent light (cycles of 2s with 1s light on & 1s with light off for 120s); Group 4) intermittent light (cycles of 3s with 1s light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins. Pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 < 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05). It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.

The Physiological Efficacy of Aloe Gel (Aloe Gel의 생리 효과에 대한 고찰 - Gel의 다당류와 미량 성분을 중심으로 -)

  • 서화중
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.24 no.6
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    • pp.1026-1038
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    • 1995
  • Although aloe lost a lot of its previous popularity in modern clinical uses as medicine numerous scientific researches still have claimed the beneficial properties(curing and general tonic effect) of aloe gel. Whereas considerable contradictory reports have helped to confuse the aloe gel issue and continually aroused controversy about aloe gel efficacy. However health food, cosmetic and medicinal products made from aloe gel are widely available in the world market especially in U.S.A. so the growing of Aloe plant and the processing of A. vera gel have become big industries in some countries. In some previous papers the salicylic acid, one of the common trace gel components, was thought to have an analgetic and antinflammatory effect. Large amount of Mg ion in the gel was suggested to act as anesthetic, Mg-lactate as antihistamic, and Aloctin A(a glycoprotein) as wound healer by promoting the cell growth. The carboxypeptidase and bradykinase activity in the gel were proposed to have the pain relieving and antiinflammatory effect. But any of thes etheories concerining the physiological action of the trace gel components has not been demonstrated by modern pharmacology, and failed to be supported by clinical research. It was suggested by some research workers that trace amount of anthraquinone compounds in the gel play an important role to act as false substrate inhibitors for PG and TX production(antiprostanoid effect), by which, they believed, inflammation, burn and frostbite, and infected wound could be healed. This hypothesis has not been substantiated. Butthe suggested antimicrobial action, antidiabetic, and antidotic effect of aloe gel are likely to be attributed to the trace anthraquinone compounds. In a lot of recent experimental reports it has been claimed that aloe gel polysaccharides(acetylglucomannan, acetylmannan, and glycoprotein) have the antimicrobial, antinflammatory, antitumour, and infected wound healing effect by immunoenhancement. It is hoped that these effects will be soon documented in clinical studies, then the controversy on aloe gel beneficial effect will cease. In the 30 days subchronic toxicity test the lowest observed adverse effect level of acemannan(acetylmannan) on dog was 5.0 mg/kg, IP. But the aloe gel is generally agreed to be harmless and non toxic even for the internal use such as health food. In the case of idiosynrasy one must keep the delayed type hypersensitivity reaction of aloe gel in mind. In conclusion it seem to be impossible to simply refuse a lot of evidences made by research workers who have claimed aloe gel's beneficial effects and to deny the fact that there had been long therapeutic histories of Aloe plants.

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Immuno-stimulating and Antitumor Effects on Mouse Sarcoma 180 by Crude Polysaccharides Extracted from Fruiting Body of Hericium erinaceus (노루궁뎅이(Hericium erinaceus) 자실체 추출 조다당류의 생쥐 Sarcoma 180에 대한 면역증강 및 항암 효과)

  • Choi, Yon-Il;Lee, Jae-Seong;Lee, U-Youn;Lee, Tae-Soo
    • Journal of Life Science
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    • v.20 no.4
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    • pp.623-631
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    • 2010
  • Hericium erinaceus, an edible and medicinal mushroom belonging to the Basidiomycota family, has been used for curing gastric ulcers and stomach cancers in human beings and is also known to have good inhibitory effects on sarcoma 180 and Ehrlich carcinoma in mice. Neutral saline soluble (0.9% NaCl), hot water soluble and methanol soluble substances (hereinafter referred to as Fr. NaCl, Fr. HW and Fr. MeOH, respectively) were extracted from the fruiting body of the mushroom. In in vitro cytotoxicity tests, crude polysaccharides were not cytotoxic against cell lines such as Sarcoma 180, HepG2, HT-29 and NIH3T3 at concentrations of $10{\sim}2,000\;{\mu}g/ml$. Intraperitoneal injection with crude polysaccharides exhibited a life prolongation effect of 29.1~54.1% in mice previously inoculated with Sarcoma 180. Fr. Na increased the numbers of spleen cells by 2.9 fold at a concentration of $50\;{\mu}g/ml$ compared with the control. Fr. Na improved the immuno-potentiating activity of B lymphocytes by increasing alkaline phosphatase activity by 5.5 fold compared with the control at a concentration of $200\;{\mu}g/ml$. Fr. NaCl increased the numbers of peritoneal exudate cells and circulating leukocytes by 4 and 2.3 folds at a concentration of 50 mg/kg, respectively. Therefore, the crude polysaccharides extracted from the fruiting body of H. erinaceus could improve antitumor activities in mice.

Dietary Effect of Liriopis Tuber Water Extracts on the Level of Blood Glucose and Serum Cholesterol in Streptozotocin-Induced Diabetic Rat (맥문동 물 추출물의 식이가 Streptozotocin으로 유도한 당뇨 흰쥐의 혈당과 혈청 콜레스테롤 함량에 미치는 영향)

  • Im Jung-Gyo;Kang Myung-Su;Park In-Kyung;Kim Soon-Dong
    • Journal of the East Asian Society of Dietary Life
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    • v.15 no.1
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    • pp.20-28
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    • 2005
  • The dietary effect of water extracts of Liriopis tuber(WELT) in the diabetic SD-rats on the level of blood sugar and serum cholesterol was investigated. The experimental plots divided into normal group(N), diabetic control(DC), 5% WELT-group(WELT-I) and 10% WELT-group (WELT-II). Each group was fed for 6 weeks, then continuously fed for 1 more week after streptozotocin injection. The loss of the body weight fed for one week after induction of the diabetes was 2.2~6.3% in the WELT-I and -II groups, but it was 18.6% in the DC-group. There was no significant difference in the feed intakes after diabetes induction between N-group and WELT-group, while it was significantly increased in DC-group. The feed efficiency ratios before diabetes induction were 1.70 in WELT-I group, 1.53~1.59 in the N, DC and WELT-II group, while the ratios after diabetes induction were 0.92 in DC-group, 1.51~1.83 in the N, WELT-I and -II group. While the amounts of water intakes for one week after diabetes induction was 625.4 mL in the DC-group, and it were 364.3~371.1 mL in the WELT-groups showing no significant difference with N-group. The excretion amounts of urine were 431.96 mL in DC-group for one week after diabetes induction, and it was 182~192.84 mL in WELT-groups. The ratios of liver weight against body weight were 2.74% in N-group, 2.93~2.96% in WELT-groups, but it was 4.01% in DC-group. The level of blood glucose in WELT-groups fed for one week after diabetes induction were 136.8~138.6 mg/dL showing no significant difference with N-group, but it was 357.8 mg/dL in DC-group. The level of serum triacylglycerol and serum total cholesterol were 93.8 and 68.7 mg/dL in N-group, 120.1 and 101.6 mg/dL in DC-group, 97.4~100.6 and 60.8~67.7 mg/dL in WELT-groups, respectively, showing no significant difference between N-group and WELT-groups. HDL-cholesterol/total cholesterol ratio were 0.63 in N-group, 0.57~0.67 in WELT -groups, which was significantly higher than that of DC-group(p<0.05). Atherogenic index were 0.58 in N-group, 0.49~0.74 in WELT-groups, but it was 1.32 in DC-group. The above results suggest that the WELT diets may have both preventive and curing effects against the diabetes.

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Cyclic behavior of RT-cement treated marine clay subjected to low and high loading frequencies

  • Al-Bared, Mohammed A.M.;Harahap, Indra S.H.;Marto, Aminaton;Mohamad, Hisham;Abad, Seyed Vahid Alavi Nezhad Khalil;Mustaffa, Zahiraniza
    • Geomechanics and Engineering
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    • v.21 no.5
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    • pp.433-445
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    • 2020
  • The weakening and softening behavior of soft clay subjected to cyclic loading due to the build-up of excess pore water pressure is well-known. During the design stage of the foundation of highways and coastal high-rise buildings, it is important to study the mechanical behavior of marine soils under cyclic loading as they undergo greater settlement during cyclic loading than under static loading. Therefore, this research evaluates the cyclic stress-strain and shear strength of untreated and treated marine clay under the effects of wind, earthquake, and traffic loadings. A series of laboratory stress-controlled cyclic triaxial tests have been conducted on both untreated and treated marine clay using different effective confining pressures and a frequency of 0.5 and 1.0 Hz. In addition, treated samples were cured for 28 and 90 days and tested under a frequency of 2.0 Hz. The results revealed significant differences in the performance of treated marine clay samples than that of untreated samples under cyclic loading. The treated marine clay samples were able to stand up to 2000 loading cycles before failure, while untreated marine clay samples could not stand few loading cycles. The untreated marine clay displayed a higher permanent axial strain rate under cyclic loading than the treated clay due to the existence of new cementing compounds after the treatment with recycled tiles and low amount (2%) of cement. The effect of the effective confining pressure was found to be significant on untreated marine clay while its effect was not crucial for the treated samples cured for 90 days. Treated samples cured for 90 days performed better under cyclic loading than the ones cured for 28 days and this is due to the higher amount of cementitious compounds formed with time. The highest deformation was found at 0.5 Hz, which cannot be considered as a critical frequency since smaller frequencies were not used. Therefore, it is recommended to consider testing the treated marine clay using smaller frequencies than 0.5 Hz.

Study of literature on the Trigeminal Neuralgia for cooperative treatment of Oriental and Occidental medicine (韓.洋方 協診治療를 위한 三叉神經痛의 文獻的 硏究)

  • Sung, Byung-Gon;Oh, Chun-Keun;Lim, Kyu-Sang
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.13 no.2
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    • pp.112-139
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    • 2000
  • I examined and referred to literatures of every generations on the nicknames, causes, herb medications and acupucture treatments of ptosis(上胞下垂). And then the results were obtained as follows. We've compared and analyzed Occidental and Oriental medical causes, symptoms and treatments of Primary trigeminal neuralgia and wanted to get better effects by a cooperative analysis. So the examination and analysis of the recent treatment tendency and reference bibliography show the following results. 1. Trigeminal neuralgia is nerve systematic disease appearing in the distribution scope of trigeminal nerve. It's characterized by extreme pain accompanying with a repeated and simultaneous fit from several seconds to 1-2 minutes. 2. Though there are many hypothesis on the trigeminal neuralgia, but now many doctors agree that when trigeminal nerve is under the local out of sheath conditions resulting from receiving a chronic stimulus, and the nucleus of trigeminal nerve fire, owing to decrease of pain control function and abnormal occurrence of action potential, it would be appeared. 3. The Oriental medical name of trigeminal neuralgia is generally Dootong, Doopoong, Myuntong, Pyundootong, Pyundoopoong, and Myuntong is the nearest in Occidental medicine. 4. The Oriental medical cause of trigeminal neuralgia is usually divided into Wekam and Naesang. The first one is caused by Poonghan, Poongyul, Damhwa and wicked energy enter into the body, the mechanical energy is obstructed and can't move any more, so the pain appears by them. The other cause is the hurt by emotion. And it would be loss of the transportain of liver and obstructed, so result into Kanwulhwahwa, Kanpoongnaedong and the pain appears. 5. There are two methods of curing trigeminal neuralgia. As a medication, primary method is prescribing Carbamazepine and the second is using Phenytoin or Baclofen. And as a operation, Drug injection of trigeminal nerve, Amputation of branches of trigeminal nerve, Retrogasserian glycerol rhizotomy, Radiofrequency gangliolysis, Neurovascular decompression can be used. 6. There are several herb medicines for Trigeminal neuralgia. First, Chungung is good for Hwaejeetong, Keopoongjedam, Hwalhyuljeetong. Second, Jeongal, Jiryong, Okong is used for Sikpoonghekyung, Tongkyungjeetong. Third, Baekjee, Sesin, Cheonma, Manhyungja is efficacious in Sinonhepyo. Sanpoongjeetong. Fourth, for falling of liver's Wulhwa, Yongdamcho, Hyungge, Kukwha can be used. And also Saengjihwang, Hwangkm is good for going down the fever of Yangmyungwiyul and finally, Baekkangjam. Moryu can be effective for Jaumjamyang, Haekyungjitong. The other medicines can be used as assistant analgesics, and it also efficacious. 7. Generally the points of pain on the face and the points of Soyangkyung and Yangmyungkyung is used for Acupuntual therapy, because the two meridians passed on the face. Hakwan. Sabaek, Kwanryo, Keoryo, Hyubkeo, Taeyang, Jeechang, Younghyang, Eoyo, Chanjuk. Yangbaek. Sajukkong. Dooyoo, Kwangsangjum, Sengjang, Poongjee is used for taking near point and Joksamlee, Naejung, Habkok is used for taking distant point. 8. Dansam or Danggui injection which have a effect for Hwalhyulhwaeo, Sokyunghwalak and Vit B1, Vit B2, Vit B12, $2\%$ Hydrochloroprocaine, $1\%$ Lidocaine injection to pain point for local analgesics had so good effect. And external application and moxibustion are used for another treatment. 9. It proved that through mouse model, both Herb medication group and Drug medication group are efficacious for trigeminal neuralgia similarly and also the cooperative medication group shows more effective result than the only drug medication group.

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Effect of delayed time, surface treatment, and repair material on shear bond strength of repaired bis-acryl composite resin (수리된 비스 아크릴 복합 레진의 전단결합강도에 대한 지연시간, 표면처리, 수리 재료의 영향)

  • Park, Ji-su;Lee, Jae-In
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.2
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    • pp.89-96
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    • 2018
  • Purpose: The aim of this study was to evaluate the effect of delayed time, surface treatment, and repair materials on repair of bis-acryl composite resin through comparison of shear bond strength and to evaluate the utility of bis-acryl composite resin repair using polymethyl methacrylate resin. Materials and Methods: A total of 90 bis-acryl composite resin specimens were fabricated and classified into 9 test groups, each of 10 pieces according to delayed time, surface treatment and repair material. The shear bond strength of each specimen was measured using a universal testing machine immediately after fabrication and analyzed using a statistical analysis program (IBM SPSS statistics 20). After the shear bond strength measurement, the fracture surface of the specimen was observed. Results: The highest shear bond strength ($17.54{\pm}3.14MPa$) was observed in the experimental group bonded immediately with a light-curing flowable composite resin using a bonding agent. Conclusion: When repairing bis-acryl composite resin, it is necessary to consider whether to remake according to the delayed time. For effective repair, it is desirable to consider appropriate materials and surface treatment methods according to the site or purpose of use.

Effect of Lotus (Nelumbo nucifera) Leaf Extract on Serum and Liver Lipid Levels of Rats Fed a High Fat Diet (고지방 식이와 병행 섭취한 연잎 추출물이 흰쥐의 혈청 및 간 조직 지질 함량에 미치는 영향)

  • Lee, Kyung-Seok;Lee, Ki-Young
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.11
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    • pp.1544-1547
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    • 2011
  • Lotus (Nelumbo nucifera) leaf is known to be effective for 'overcoming body heat' and stopping bleeding. It is commonly used as a traditional curing plant for the treatment of hematemesis, epistaxis, hemoptysis, hematuria, and metrorrhagia in traditional Chinese medicine. This study investigated on the effect of oral administration of lotus (Nelumbo nucifera) leaf extract on the serum and liver lipid levels of rats fed a high fat diet. Experimental rats were divided into five different experimental groups, including the general diet group (Cont), high fat diet with lotus leaf extract groups (HL40, HL80, HL120), and high fat diet group (HFG). Body weight significantly decreased in the HL120 sample compared to that of Cont. The weights of the livers and kidneys of rats corresponded to the increase in body weight. Total cholesterol and triglyceride contents in liver tissues of rats were lowest in the sample HL120 sample. The levels of total lipids, total cholesterol, and triglycerides in serum were lower in the HL120 sample compared to the HFG.

A Study on the Manufacturing Processability of Automatic Winding Device for Manufacturing Strand Specimens (스트랜드 시편 제작 장치의 제작 공정성 연구)

  • Cha, Jae Ho;Jang, Jeong Keun;Lee, Bo Mi;Yoon, Sung Ho
    • Composites Research
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    • v.33 no.5
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    • pp.315-320
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    • 2020
  • In this study, when strand specimens were manufactured using an automatic winding device to obtain uniform strand specimens, analysis and test were conducted to investigate the effect of thermal expansion of the mandrel on strand specimens. Also, necessity of changing materials and mandrel configuration was checked. According to the results, strand specimen received unintended tension that was created by thermal expansion of the mandrel and this unintended tension depended on the curing temperature and position of specimens. Tensile test was conducted to check that initial tension affected on the performance of carbon fiber tow prepreg. All other conditions were fixed and only the initial tension was controlled at 40 N, 60 N, and 80 N. From the results of analysis and test, neither additional tension and tension deviation due to the thermal expansion of the mandrel and the initial tension difference had a significant effect on tensile test results, because carbon fiber had sufficiently high strength compared with tension. Therefore, it was confirmed that the change of the mandrel material and configuration of the automatic winding device was unnecessary.

Effects of Particle Size of Fly Ash on the High Strength of Hardened Cement Mortar (시멘트 모르터 경화체의 고강도화에 미치는 플라이 애쉬 입자크기의 영향)

  • 김영수;김정환
    • Magazine of the Korea Concrete Institute
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    • v.6 no.5
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    • pp.131-139
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    • 1994
  • The min aim of thls study was to evaluate the effect of particle slze of the fly ash as a cement additive. Experimental work was carried out with three different sizes of fly ash. 18.58, 8.95 and 4.02{$mu}m$ in average radius. Namely, the effect of particle size variation of fly ash on the physical properties of cement paste was investigated. The jluidity was decreased with increasing the addition of fly ash to cement paste regardless of the particle size variation. The decrement of the fluidity of the pulverized fly ash was higher than that of the spherical fly ash. On the other hand, the pozzolan reactivity increased with lowering particle size. In the case of specimens with 5% up to 10% addition of fly ash having a particle size of 4.02{$mu}m$. the compressive strength was increased as compared with the plain specimens before curing for 28 days and showed higher value above 800kg /$cm^2$ when cured for 60 days.This increased compressive strength was ascribed to both the closer packlng of fine particles and the pozzolan reactivity of fly ash. These results were comfirmed by measuring both the porosity of the specimens and Ca(OH ), contents remained in specimens. This work showed that could be effectively ut~lized as a blending material without any de crease in the strength of early hydration stage if we can control the particle size of fly ashes by sizing or pulverizing.