• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.99-100
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• 2006

Orthogonally protected block copolymers of based on p-hydroxystyrene were prepared with high control via nitroxy mediated radical polymerization using an alkoxyamine as an unimolecular initiator. Thin films of partially protected block copolymer were prepared by spin or dip coating. A well defined nanostructure could be observed as a result of phase separation e.g. cylinders in a matrix oriented perpendicular or parallel to the substrate. The nanostructure of the polymeric films can be defined by the block copolymer composition and it determines surface properties and allows further, selective functionalization, e.g. via click chemistry. The thin films can be designed in a way to allow a patterning based on a thermal or photochemical stimulus.

• Economic and Environmental Geology
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• v.31 no.1
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• pp.45-52
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• 1998

Paleomagnetic data have been obtained from the Lower Triassic Tonggo Formation which is exposed in Tanyang area comprising the Pyeongan Supergroup in eastern Korea. Mean characteristic direction of the Tonggo Formation is declination/inclination=$121.4^{\circ}/-26.4^{\circ}$ (k=52.7, ${\alpha}_{95}=7.2^{\circ}$, N=9 Sites) and paleopole at longitude/latitude=$30.7^{\circ}E/33.3^{\circ}N$ ($dp/dm=4.2^{\circ}/7.8^{\circ}$). The mean direction passes reversal test and fold test at 99% confidence level. Therefore, it is inferred to be a pre-folding component. The paleopole position of this study is close to the Triassic pole positions of the North China Block; it is far from those of the South China Block. Therefore, a first order correlation between the Korean Peninsula and North China at least since Lower Triassic times is identified in this study.

• The Korean Journal of Pain
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• v.10 no.1
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• pp.124-126
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• 1997

Stellate ganglion block is the most widely practiced procedure in the pain clinics due to its wide range of indications. We experienced a rare case who exhibited severe hematoma in neck following stellate ganglion block. A 58-year-old female patient injured by a traffic accident was admitted to the department of negro surgery for the treatment of cerebral contusion, cervical and lumbar sprain and left arm paresis. Because left sensory neural hearing loss occurred, the patient was referred to the pain clinic for treatment with stellate ganglion block due to her left sensory neural hearing loss. The next day stellate ganglion block was done with a negative aspiration for blood. Three hours later, hematoma in neck was found and the patient complained of pain in the neck and dyspnea. The symptoms and signs of respiratory difficulty were progressively aggravated. The hematoma was removed and ruptured muscular branch of vertebral artery was ligated under surgical exploration. In this case, the needle was apparently in the branch of vertebral artery during or after injection in spite of the negative aspiration for blood. Authors recommend that compression of the injected site over 5 minutes should be necessary to prevent a hematoma formation despite of a negative aspiration for blood.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.346-349
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• 1998

The technique of the stellate ganglion block is widely used as it is relatively simple and safe. But it can cause severe complications because there are major blood vessels and nerves around the stellate ganglion. We practiced CPR because of the respiratory failure caused by severe hematoma in the neck following the stellate ganglion block. A 46-year-old male patient admitted to ENT department because of the both sudden sensorineural hearing loss that happened after URI. He was referred to Pain Clinic for further evaluation and treatment. We decided to block the stellate ganglion. We injected 6ml of 0.5% mepivacaine on both sides of the stellate ganglion. There were no blood aspiration and abnormal vital signs during the 30 minute observation, either. Three hours after he went to the private room, he had pain and edema in his neck, but no respiratory defficulty. But later, respiratory failure was suddenly followed. So we practiced CPR. We confirmed severe hematomas in the neck through CT scanning. Hematomas is removed and the ruptured blood vessels which is supposed to be muscular branch of vertebral artery is ligated under general anesthesia. The patient was discharged from hospital after the treatment of pneumonia and duodenal ulcer as complications. We recommand you to compress the block site more than five minutes and not to prick with the needle several times at one point to prevent the formation of hematomas.

• The Korean Journal of Pain
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• v.10 no.2
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• pp.285-290
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• 1997

Horner's syndrome is a well-recognized complication of regional analgesia of neck and shoulder region, and not often a complication of lumbar or low thoracic epidural block. Recently we experienced right Horner's syndrome accompanying paralysis of right upper extremity following lumbar epidural block in for an obstetric patient. Epidurography and MRI was performed to clarify the cause of unilateral high epidural block and cervical sympathetic block. Radiologic study demonstrated a loop formation of the epidural catheter and tip of catheter was located in right anterior epidural spaced(L1-2). The initial epidurogram revealed unilateral spreading of dye in the cervical region in right epidural space. A second epidurogram, 10 minutes following, showed dye filling in left epidural space, however spread of dye in left side was limited to lumbar and low thoracic region. We concluded the most probable cause of this unilateral high epidural block was due to misplacement of the catheter into the anterior epidural space.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.397-407
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• 2007

골형성 유도 단백질(bone morphogenetic protein, BMP)은 성장이나, 골형성과정에서 중용한 역할을 한다고 입증되었고 그것의 운반체에 대한 연구가 이뤄져 왔다. 하지만 수직압이 존재하는 곳에서 골증대술에 적용할 수 있을 만큼 강한 공간유지능력이 있는 운반체에 대한 연구는 그리 많지 않았다. Macroporous biphasic calcium phosphate block (MBCP block)은 공간유지능력이 뛰어나며 강한 수직압을 견딜수 있는 골대체물질이다. 이 연구의 목적은 MBCP block을 골형성유도 단백질(rhBMP-2)의 운반체로 사용하여 백서 두개골 결손부에 적용하였을 때, 골 형성 효과를 평가하는 것이다. 36마리의 웅성백서에서 8mm 지름을 갖는 임계크기의 두 개부 결손을 형성하였다. 20마리씩 2개의 군으로 나누어 MBCP block만 이식한 군, MBCP block을 운반체로 사용하여 농도 0.025mg/ml rhBMP-2를 이식한 군으로 나누어 술 후 2주와 8주에 치유결과를 조직학적, 조직계측학적으로 비교 관찰 하였다. 조직계측학적 관찰 결과, rhBMP-2/MBCP block 군에서 MBCP block군에서 보다 2, 8주 모두 골밀도(bone density)가 유의성있게 증가하였다 (P<0.01). 각 군에서도 8주째가 2주째보다 골밀도가 유의성있게 증가하였다(P<0.01). 총조직 형성량 (augmented area)에서는 변화가 없었다. 이 연구 결과, 백서 두개골 결손부에서 MBCP block은 rhBMP의 운반체로 사용하였을 때 신생골 형성에 유의한 효과가 있을뿐 아니라 공간유지능력이 우수해서 수직압이 존재하는 골증대술(bone augmentation)시 rhBMP의 운반체로 가능성이 있다고 사료된다.

• Animal cells and systems
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• v.9 no.2
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• pp.57-64
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• 2005

Cortical reaction and polyspermy block are well defined in most marine invertebrates. In Urechis species, the function of cortical granules (CGs) is not yet known, and there is controversy on whether the cortical reaction occurs, or the fertilization envelope (FE) is attributed to CG releases or functions to prevent polyspermy. This study was carried out to determine the cortical reactions and functions of the FE in Urechis unicinctus. Artificial insemination of the eggs revealed that CG release occurred to give rise to perivitelline space (PS) into the final FE. Both PS and final FE effectively blocked polyspermy. The final FE was accomplished within 10 min after sperm-egg initial binding. No massive release of CGs occurred within the early phase of 5 min after the initial binding, initially and the PS seemed to playa role to prevent polyspermy. The CG massively released its content into the PS in late phase of FE formation, and differentiated PS into five intermediate layers. The layers opened into each other by anastomosis, so that the final FE consisted of two layers, the inner layer ($15{\mu}m$ in thickness) and the outer layer ($1{\mu}m$ in thickness). The outer layer derived from vitelline layer and the inner layer consisted of PS and CG secretions. Immunofluorescence and confocal laser microscopy revealed that the spermatozoon took up residence in the egg cortex during FE formation and successive meioses of the fertilized egg. These results suggest that both PS and final FE of U. unicinctus were equivalent to the early and late block, respectively, of other marine animals.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.4
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• pp.278-286
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• 2011

Introduction: This study examined the predictability of new bone formation in the pneumatized maxillary sinus using only fibrin-rich blocks with concentrated growth factors as an alternative to bone grafts. Materials and Methods: Maxillary sinus augmentation was performed in thirty-three patients with a deficient alveolar bone height (mean 3.9 mm). All patients were treated consecutively with sinus membrane elevation via the lateral window approach and panoramic radiograms and cone-beam computed tomograms were taken to evaluate the remaining bone height and the new bone formation in the maxillary sinus, before and after surgery. Four biopsy specimens were taken at the time of implant consolidation (after an average of five months healing) and were stained by H & E and Trichrome staining. Results: None of the patients had postoperative complications during implant consolidation. After an average of 5 months since sinus augmentation, newly formed bone was observed in all cases by a radiographic evaluation. In 4 biopsy samples, newly formed bone was observed along the floor of the replaced bony window. The osteoblast lining and well distinguished Osteocytes in the lacunas were observed in the newly formed bone. Of the 74 implants (4 different surfaced implants - resorbable blast media-surfaced (RBM), Hydroxyapatite (HA) coated, acid-etched, sintered porous-surfaced implant) placed, one RBM implant failed. The success rate was 98.6% after a mean of 15 months. Discussion: These results suggest that maxillary sinus augmentation using fibrin rich block with concentrated growth factors is a successful and predictable technique.

• Journal of Chest Surgery
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• v.54 no.1
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• pp.31-35
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• 2021

Background: Arteriovenous fistula (AVF) for hemodialysis is essential for patients with end-stage renal disease. However, it is difficult to maintain AVF reliably. It is vitally important to select proper blood vessels for AVF formation. In a previous study, a minimum diameter of 3 mm for the autologous vein was proposed. However, patients who did not meet the minimum vascular diameter before anesthesia, but fulfilled other criteria, showed satisfactory venous dilatation after brachial plexus block (BPB). This study investigated the extent of vein expansion by BPB and the surgical outcomes of dilated veins after BPB. Methods: Sixty-one patients who underwent AVF formation using an autologous vein between August 2018 and December 2019 were included in the study. The clinical characteristics of the patient groups, hemodynamic parameters including the diameter of blood vessels before and after BPB, and complications were investigated. Based on the venous diameter measured by sonography before anesthesia, patients were divided into group A (26 patients) and group B (35 patients), with venous diameters <3 mm and ≥3 mm, respectively. Results: The venous diameter expanded after anesthesia by 41% overall, by 62% in group A, and by 25% in group B. This difference between groups A and B was statistically significant (p=0.001). No other variables showed statistically significant differences. Conclusion: Sufficient venous dilatation was observed after BPB. Therefore, if the vein is sufficiently dilated after BPB, even in patients with a pre-anesthesia venous diameter <3 mm, surgery may still be performed with an expected desirable outcome.

• Clean Technology
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• v.17 no.3
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• pp.244-249
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• 2011

We synthesized low molecular-weight polymers bearing hydrophobic and hydrophilic parts in a chain through $CO_2$/propylene oxide copolymerization. When hydrophilic poly (ethylene glycol) bearing -OH group (s) at the end group (s) was added as a chain transfer agent in the $CO_2$/propylene oxide copolymerization catalyzed by a highly active catalyst, block polymers were formed. If poly (ethylene glycol) (PEG) bearing -OH group only at an end was fed, PEG-block-PPC diblock copolymer was obtained. When PEG bearing -OH group at both ends was fed, PPC-block-PEG-block-PPC triblock copolymer was obtained. We confirmed formation of block copolymers by $^1H$-NMR spectroscopy and GPC studies.