• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1461-1466
• /
• 2008

In the case of Posterior Cruciate Ligament (PCL), the most frequent mechanism is the dashboard injury, which is directly pressurized to the anterior of the proximal tibia in the state of the knee hyperflexion. The PCL associated ligament damage happens when the posterior injury, the varus, the valgus, the hyperextension and the severe vagus torque are out of the critical value of PCL. After the successful operation cases of Anterior Cruciate Ligament (ACL) reconstruction using the allograft were informed from 1986, a number of results kept over the maximum 10 years were reported. Unfortunately, PCL reconstruction are crowded the surgery techniques such as the graft, the tibia fixing method, the fixation device, the location of the femoral tunnel, the number of the graft bundles and PCL reconstruction to access to the stability of the normal joint is being developed. Therefore, this study is the basic research of these above facts. The current transtibial tunnel surgery using the cadaveric Achilles tendon grafts is chosen for the various PCL reconstruction. The initial extension of the Achilles tendon by the fixing device and its location under the cyclic loading, were observed.

• Archives of Pharmacal Research
• /
• v.27 no.12
• /
• pp.1284-1289
• /
• 2004

Galactosylated chitosan-graft-poly(vinyl pyrrolidone) (GCPVP) was synthesized and characterized for hepatocyte-targeting gene carrier. GCPVP itself as well as GCPVP/DNA complex had negligible cytotoxicity regardless of the concentration of GCPVP and the charge ratio, but GCPVP/DNA complex had slightly cytotoxic effect on HepG2 cells only in the case of the higher charge ratio and 20 mM of $Ca^{2+}$ concentration used. Through the confocal laser scanning microscopy, it is shown that the endocytosis by interaction between galactose ligands of GCPVP and ASGPR of the hepatocytes was the major route of transfection of GCPVP/F-plasmid complexes.

• Nuclear Engineering and Technology
• /
• v.8 no.3
• /
• pp.159-168
• /
• 1976

Acrylic acid has been grafted onto nylon fabric with ceric salts and ${\gamma}$-rays from Co-60 as initiators. The distribution of molecular weight of the grafted polyacrylic acid has been determined and it was found that the ratio of weight-average and number-average molecular weight was higher in room temp. than in low temp. (-184$^{\circ}C$). The weight-average molecular weight of the polyacrylic acid was calculated from viscosity measurements in sodium hydroxide solution. The factors affecting graft polymerization of acrylic acid onto nylon were examined. A possible mechanism that the oxidation of nylon probably takes place at the methylene group attached to nitrogen to give a free-radical was discussed.

• Asian Journal of Turfgrass Science
• /
• v.9 no.1
• /
• pp.1-10
• /
• 1995

This study was carried out to investigate the method of propagation of Lindera erythrocarpa Makino. The results were as follows: 1. After the treatment of warm stratification for 1 month followed by cold stratification for 3 months, the germination ratio of seeds of Lindera erythrocarpa was from 84.6 to 93.6 percent. But, dry stored seeds lose their viability Quickly and should be placed in pretreatment im-mediately. Also, the seeds of control district germinated from 68.6 to 74.6 percent. So it was confirmed that the seed of Lindera erythocaeicarpa was not doubly dormant. 2. Softwood cuttings of Lindera erythrocarpa with 5,000 ppm IBA on August 4. 1992 resulted in the best rooting of 95.0 percentage. 3.Twenty percent of the graft union were obtained in the green wood grafting in Lindera erythrocarpa on June 7, 1993. And five percent of the graft union were obtained in the hard wood grafting in Lindera erythrcoar pa on April 6. 1993.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.33 no.1
• /
• pp.28-39
• /
• 2007

The purpose of this study is to evaluate the regenerative capacity of reconstruction in the atrophied posterior maxilla by comparing bone graft procedures and alveolar distraction osteogenesis (ADO) techniques. We performed the autogenous iliac bone graft (AGB group, 5 specimens in 3 patients), and the combination (Mixed group, 3 specimens in 3 patients) of the autogenous and deproteinized bovine bone ($Bio-Oss^{(R)}$, Geistlich Co., Switzerland) as the ratio of 2:1 in the sinus floor elevation procedures. ADO procedures using $TRACK^{(R)}$ (KLS Martin Co., Germany) were also performed to augment vertical alveolar height in atrophied posterior maxilla (ADO group, 5 specimens in 4 patients). Newly generated bone tissues were obtained with the 2.0mm diameter trephine bur (3i Co., USA) during implant fixture installation after 5-7 months. Routine histolomorphological observation, immunodot blot assay for quantitative evaluation, and immunohistochemical staining with antibodies to MMP-1, -9, -10, TIMP-1, -2, and BMP-2, -4 were all carried out. Lamellar bone formation was well shown in all specimens and new bone formations of ADO group increased than those of other procedures. In immunohistochemical staining, the strong expression of BMP-2 was shown in all specimens, and immunodot blot assay showed that bone formation is accompanied by the good induction of factors associated with angiogenesis and appeared more increased amount of osteogenic and angiogenic factors in ADO group. ADO is the most effective technique for new bone formation compared to sinus floor elevation with autogenous or mixed bone graft in the atrophied posterior maxilla. In the quantitative immunodot blot assay, the regenerated bone after ADO showed more increased products of VEGF, BMP-2, PCNA and MMP-1 than those after the other procedures, and these findings were able to be confirmed by immunohistochemical stainings.

• Journal of Periodontal and Implant Science
• /
• v.47 no.1
• /
• pp.51-63
• /
• 2017

Purpose: Following tooth extraction, alveolar ridge preservation (ARP) can maintain the dimensions of ridge height and width. Although previous studies have demonstrated the effects of ARP, few if any studies have investigated the compressive force applied during grafting. The aim of this study was to determine the effects of different compressive forces on the graft materials during ARP. Methods: After tooth extraction, sockets were filled with deproteinized bovine bone mineral with 10% porcine collagen and covered by a resorbable collagen membrane in a double-layered fashion. The graft materials were compressed using a force of 5 N in the test group (n=12) and a force of 30 N in the control group (n=12). A hidden X suture was performed to secure the graft without primary closure. Cone-beam computed tomography (CBCT) was performed immediately after grafting and 4 months later, just before implant surgery. Tissue samples were retrieved using a trephine bur from the grafted sites during implant surgery for histologic and histomorphometric evaluations. Periotest values (PTVs) were measured to assess the initial stability of the dental implants. Results: Four patients dropped out from the control group and 20 patients finished the study. Both groups healed without any complications. The CBCT measurements showed that the ridge volume was comparably preserved vertically and horizontally in both groups (P>0.05). Histomorphometric analysis demonstrated that the ratio of new bone formation was significantly greater in the test group (P<0.05). The PTVs showed no significant differences between the 2 groups (P>0.05). Conclusions: The application of a greater compressive force on biomaterials during ARP significantly enhanced new bone formation while preserving the horizontal and vertical dimensions of the alveolar ridge. Further studies are required to identity the optimal compressive force for ARP.

• Journal of Chest Surgery
• /
• v.54 no.2
• /
• pp.81-87
• /
• 2021

Background: Artificial grafts such as polyethylene terephthalate (Dacron) and expanded polytetrafluoroethylene (ePTFE) are used for various cardiovascular surgical procedures. The compliance properties of prosthetic grafts could affect hemodynamic energy, which can be measured using the energy-equivalent pressure (EEP) and surplus hemodynamic energy (SHE). We investigated changes in the hemodynamic energy of prosthetic grafts. Methods: In a simulation test, the changes in EEP for these grafts were estimated using COMSOL MULTIPHYSICS. The Young modulus, Poisson ratio, and density were used to analyze the grafts' material properties, and pre- and post-graft EEP values were obtained by computing the product of the pressure and velocity. In an in vivo study, Dacron and ePTFE grafts were anastomosed in an end-to-side fashion on the descending thoracic aorta of swine. The pulsatile pump flow was fixed at 2 L/min. Real-time flow and pressure were measured at the distal part of each graft, while clamping the other graft and the descending thoracic aorta. EEP and SHE were calculated and compared. Results: In the simulation test, the mean arterial pressure decreased by 39% for all simulations. EEP decreased by 42% for both grafts, and by around 55% for the native blood vessels after grafting. The in vivo test showed no significant difference between both grafts in terms of EEP and SHE. Conclusion: The post-graft hemodynamic energy was not different between the Dacron and ePTFE grafts. Artificial grafts are less compliant than native blood vessels; however, they can deliver pulsatile blood flow and hemodynamic energy without any significant energy loss.

• Applied Chemistry for Engineering
• /
• v.4 no.3
• /
• pp.627-636
• /
• 1993

Anionic acrylic resin utilizing macromer(TBMA-g-MMA) copolymer was synthesized by preparing (TBMA) macromer using anionic living polymerization, followed by graft copolymerization with MMA macromer. To control the anionic site content in graft copolymer, the relative composition((TBMA) macromer/MMA ratio) of the graft copolymer was controlled at 7/3, 10/90, 15/85, 20/80, 30/70, 40/60, 50/50 in weight content. In the course of anionic living polymerization of(TBMA) macromer, broad molecular weight distribution (1.4~1.5) was obtained by using n-butyllithium-diphenyethylene initiatior system at $-78^{\circ}C$. To introduce the double bond at the end of chain in termination step, methacryloyl chloride was reacted after insertion of benzaldehyde as capping material. Moreover, TBMA parts in graft copolymer were hydrolyzed in the presence of p-toluenesulfonic acid catalyst, and neutralization of graft copolymer with triethylamine was granted acrylic resin to anionic site. Molecular weight and molecular weight distribution of(TBMA) macromer were determined by GPC, and the hydrolysis of TBMA with neutralization of acrylic resin were determined by IR and NMR. From water dispersion and stability point of view, stable dispersion state appeared at low molecular weight(TBMA) macromer with a small TBMA content as a result of scrutiny about the relation to TBMA content and branch length for(TBMA) macromer molecular weight in graft copolymer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.2
• /
• pp.167-173
• /
• 2001

Cystic lesion of the jaw are frequently encountered clinically. Although they rarely lead to development of tumors, they can result in resorption of the jaw bone or asymmetry of the face may occur. The purpose of this study is to find the clinical and histopathological pattern of cysts and to help better understanding for the diagnosis and treatment of jaw cysts. The hospital chart, out-patient chart, panorama X-ray, histopathological report and operation report of 246 patients were reviewed who had been diagnosed as cyst. Sex distribution, age distribution, classification, anatomic distribution, clinical sign & symptoms, treatment, post-operation complications, recurrence rate were studied. Then significant difference between the diameter of cyst with bone graft and none-bone graft was calculated with SAS program. The results were as follows. 1. Among the total patient of 246 cases, male were 163 case(67.0%), and female were 83 case(37.0%), male predominated by the ratio of 1.98. 2. By age group, the 20's accounted for the largest proportion of the cases(27.2%) and the 30' accounted for the 2nd largest proportion of the case(19.5%). 3. Radicular cyst and dentigerous cyst were most common cysts, irrespective of 166 case(67.5%) and 62 case(25.2%). 4. Clinical sign & symptoms were swelling(167case), pain(85case), pus discharge(53case), teeth discoloration(28case), indicating that most complaints were related to inflammation and facial asymmetry. 4.9% of the total cases were discovered accidentally. 5. The primary site of cysts were maxillary anterior area(43.9%), the others were, in descending order, mandibular posterior area(25.6%), maxillary posterior area(14.6%). 6. Enucleation with endodontic treatment was a main treatment method(133 case, 54.1%) and 38 cases(15.4%) were enucleation with extraction, and 37 cases(15.0%) were only enucleation, and 21 cases(8.5%) were enucleation with bone graft. 7. The average diameter of cysts with bone graft was significally greater than with non-bone graft(p<0.05). 8. Post-operation complications occurred in 10 case(4.1%), all of this were due to secondary infection.

• Applied Chemistry for Engineering
• /
• v.5 no.4
• /
• pp.698-705
• /
• 1994

The basic medium oil modified alkyd resin was synthesized from linseed oil fatty acid(LOFA), phthalic anhydride(PAA), maleic anhydride(MA) and trimethylol propane(TMP) by condensation polymerization at $230^{\circ}C$. MA/TMPTA modified water-reducible alkyd resins were synthesized with TMPTA graft copolymerization onto the basic resin at $180^{\circ}C$. Acid value of the resin was controlled by the addition amount of MA and N,N-dimethylethanol amine(DMEA) was used as a neutralizing agent to prepare of the water-reducible alkyd resin. The effect of TMPTA on the graft copolymerization of the resin was studied by measuring molecular weight glass transition temperature(Tg), viscosity, graft efficiency, and gel contents of melanin cured film. Heat resistance, UV resistance and water resistance of cured film of MA/TMPTA modified resin was compared to those of TMA/TMPTA modified alkyd resin. The molecular weight, viscosity gel contents and graft efficiency of water reducible alkyd resin were increased according to the TMPTA graft copolymerization, but Tg was decreased. The viscosity was lower when the solid contents reached 40% than that of 30% content and also and also became lower with the extent of neutralization ratio, The heat resistance, UV resistance and water resistance of the MA/TMPTA modified alkyd resis were better than those of TMA/TMPTA modified alkyd resin but the storage stability of the TMA/TMPTA alkyd resis was better than that of MA/TMPTA modified alkyd resin.