• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2879-2888
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• 2023

In fusion environments, large scales of helium (He) atoms are produced by a radical transformation along with structural damage in structural materials, resulting in material swelling and degradation of physical properties. To understand its irradiation effects, this paper investigates the stability, electronic structure, energetics, charge density distribution, PDOS and TDOS, and diffusion processes of He impurities in 6HSiC materials. The formation energy indicates that a stable, favorable position for interstitial He is the HR site with the lowest energy of 2.40 eV. In terms of vacancy, the He atom initially prefers to substitute at pre-existing Si vacancy than C vacancy due to lower substitution energy. The minimum energy paths (MEPs) with migration energy barriers are also calculated for He impurity by interstitial and vacancy-mediated diffusion. Based on its calculated energy barriers, the most possible diffusion path includes the exchange of interstitial and vacancy sites with effective migration energies ranging from 0.101 eV to 1.0 eV. Our calculation provides a better understanding of the stabilization and diffusion behaviors of He impurities in 6H-SiC materials.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.101-106
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• 2000

Purpose : This study was peformed to evaluate the effectiveness and tolerance of craniospinal irradiation for patients with modulloblastoma and to define the optimal radiotherapeutic regimen. Materials and Methods : We retrospectively analyzed the records of 43 patients with modulloblastoma who were treated with external beam craniospinal radiotherapy at our institution between May, 1984 and April, 1998. Median follow up period was 47 months with range of 18 to U months. Twenty seven patients were male and sixteen patients were female, a male to female ratio of 1.7:1. Surgery consisted of biopsy alone in 5 patients, subtotal excision in 24 patients, and gross total excision in 14 patients. All of the patients were treated with craniospinal irradiation. All of the patients except four received at least 5,000 cGy to the posterior fossa and forty patients received more than 3,000 cGy to the spinal cord. Results : The overall survival rates at 5 and 7 years for entire group of patients were 57$\%$ and 56$\%$, respectively. Corresponding disease free survival rates were 60$\%$ and 51$\%$, respectively, The rates of disease control in the posterior fossa were 77$\%$ and 67$\%$ at 5 and 7 years. Gross total excision and subtotal excision resulted in 5 year overall survival rates of 76$\%$ and 66$\%$, respectively, In contrast, those patients who had biopsy alone had a 5 year survival rate of only 40$\%$. Posterior fossa was a component of failure in 11 of the 18 recurrences. Seven recurrences were isolated to the posterior fossa. Four patients had neuraxis recurrences, three had distant metastasis alone and four had multiple sites of failure, all involving the primary site. Conclusion : Craniospinal irradiation for patients with moduiloblastoma is an effective adjuvant treatment without significant treatment related toxicitles. There is room for Improvement in terms of posterior fossa control, especially in biopsy alone patients. The advances in radiotherapy including hypefractionation, stereotactic radiosurgery and 3D conformal radiotherapy would be evolved to improve the tumor control rate at primary site.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.457-464
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• 2005

The purpose of our study was to investigate whether the intrapulpal temperature during cavity preparation of enamel or dentin with Er:YAG laser still remained in range of safety for dental pulp protection when combined with appropriate water flow rate. The effect of different pulse repetition rates at the same pulse energy during ablation was evaluated as well. Caries-free, restoration-free extracted human molar teeth were prepared for the specimen and divided two experimental groups of enamel and dentin. Each group comprised 5 specimens and each of tooth specimens were embedded into a resin block each and measuring probe was placed on the irradiated pulpal walls. For experiments of dentin ablation, enamel layers were prepared to produce dentin specimen with a same dentin thickness of 2 mm. A pulse energy of Er:YAG laser was set to 300 mJ and three different pulse repetition rates of 20 Hz, 15 Hz and 10 Hz were employed. Laser beam was delivered with 3 seconds and less per application over enamel and dentin surfaces constant sized by $3\;mm{\times}2\;mm$ and water spray added during irradiation was a rate of 1.6 ml/min. Temperature change induced by Er:YAG laser irradiation was monitored and recorded While enamel was ablated, there was no significant difference of temperature related to pulse repetition rates(p=0.358) and temperature change at any pulse repetition rate was negligible. Significant statistical difference in temperature changes during cavity preparation in dentin existed among three different pulse groups(p=0.001). While temperature rise was noticeable when the dentinal wall was perforated, actual change of temperature due to Er:YAG laser irradiation was not enough to compromise safety of dental pulp when irradiation was conjugated with appropriate water spray. Conclusively, it can be said that cavity preparation on enamel or dentin with an Er:YAG laser is performed safely without pulp damage if appropriate volume of water is sprayed properly over the irradiated site.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.63-71
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• 2004

The human skin is constantly exposed to environmental irritants such as ultraviolet, smoke, chemicals. Free radicals and reactive oxygen species (ROS) caused by these environmental facts play critical roles in cellular damage. These irritants are in themselves damaging to the skin structure but they also participate the immensely complex inflammatory reaction. The purpose of this study was to investigate the skin cell protective effect of Juniperus chinensis xylem extract on the UV and SLS-induced skin cell damages. We tested free radical and superoxide scavenging effect in vitro. We found that Juniperus chinensis xylem extracts had potent radical scavenging effect by 98％ at 100 $\mu\textrm{g}$/mL. Fluorometric assays of the proteolytic activities of matrix metalloproteinase-l(MMP-1, collagenase) were performed using fluorescent collagen substrates. UV A induced MMP-1 synthesis and activity were analyzed by enzyme-linked immunosorbent assay (ELISA) and gelatin-based zymography in skin fibroblasts. The extract of Juniperus chinensis showed strong inhibitory effect on MMP-1 activities by 97％ at 100 $\mu\textrm{g}$/mL and suppressed the UVA induced expression of MMP-1 by 79％ at 25 $\mu\textrm{g}$/mL. This extract also showed strong inhibition on MMP-2 activity in UVA irradiated fibroblast by zymography. We also examined anti-inflammatory effects by the determination test of proinflammatory cytokine, interleukin 6 in HaCaT keratinocytes. In this test Juniperus chinensis decreased expression of interleukin 6 about 30％. Expression of prostaglandin E$_2$, (PGE$_2$) after UVB irradiation was measured by competitive enzyme immunoassay (EIA) using PGE$_2$ monoclonal antibody. At the concentrations of 5-50 $\mu\textrm{g}$/mL of the extracts, the production of PGE$_2$ by HaCaT keratinocytes (24 hours after 10 mJ/$\textrm{cm}^2$ UVB irradiation) was significantly inhibited in culture supernatants (p〈0.05). The viability of cultured HaCaT keratinocytes was significantly reduced at the doses of above 10 mJ/$\textrm{cm}^2$ of UVB irradiation, but the presence of these extracts improved cell viability comparing to control after UVB irradiation. We also investigated the protective effect of this extract in sodium lauryl sulfate (SLS)-induced irritant skin reactions from 24 hour exposure. Twice a day application of the extract for reducing local inflammation in human skin was done. Irritant reactions were assessed by various aspects of skin condition, that is, erythema (skin color reflectance) and transepidermal water loss (TEWL). After 5 days the extract was found to reduce SLS-induced skin erythema and improve barrier regeneration when compared to untreated symmetrical test site. In conclusion, our results suggest that Juniperus chinensis can be effectively used for the prevention of UV and SLS-induced adverse skin reactions such as radical production, inflammation and skin cell damage.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1237-1241
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• 1997

Tracheal stenosis is a difficult disease entity to manage. Laser ablation is one effective treatment for treacheal stenosis and can be utilized if tracheal reconstructive surgery is impossible. Potassium titanyl phosphate laser, transmitted via flexible quartz fiber, can be precisely manipulated through flexible bronchoscope under local anesthesia. We treated 7 patients with trach al and broncheal lesion under local anesthesia with KTP laser from January 1995 to July 1996. The patients included three males and four females. The age of patients ranged from 22 to 66 years with a mean of 43.7 years The etiology of tracheal stenosis in patients was stenosis after tracheostomy(3 cases), prolong inturbation in cases of sepsis(1 cases), and the recurrence of lung cancer within endobronchial lesion(2 cases). In the cases of tracheal stenosis treated with laser ablation, there were 2 cases of recurrence of stenosis at the anastomosis site after the operation, 3 cases of stenosis at tracheostomy site, and 2 cases of local recurrence of lung cancer. The site of the tracheal stenosis was the balloon site of the tracheostomy tube(3-4cm inferior to the tracheostomy site, 2-3cm superior to the carina) and the anastomosis site that were narrowed to less than 5mm(4 cases). For the stenosis lesion in the endobronchial area, there were 2 patients with a lesion at the anterior wa l, 1 patient with a lesion at the posterior wall, 2 patients with circumferential stenosis. Laser ablation time was 25.4 $\pm$5.9min and used energy was 1768 $\pm$365J. We have used KTP laser via (lexible bronchoscope without major complications. Adjuvant radiation therapy may prevent fibroblast proliferation which leads to restenosis. In three patients of restenosis after laser ablation, adjuvant irradiation started within 4 hours after laser ablation, and the radiation doses were 1500cGy given in five fraction. In patients with adjuvant radiation therapy, stenosis has not recurred

• Radiation Oncology Journal
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• v.6 no.2
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• pp.177-182
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• 1988

A retrospective analysis was peformed on 23 patients with pineal region tumors treated with radiation from 1979 through 1985 at the Department of Therapeutic Radiology, Seoul National University Hospital. Histologic confirmation was done in only one case by surgical removal, and in the remaining 22 patients, the diagnosis was based on clinical and radiological findings. The radiation volume was the primary tumor site in 1 case, whole brain in 14 cases, and the whole craniospinal axis En 8 cases. The overall 5 year survival was $71.5\%$. The 5 year survival was $69.3\%$ for whole brain treated group and $73.3\%$ for craniospinal axis treated group. The survival for the two groups did not differ significantly. In two cases sites of recurrence were detected, one in supratentorial area, and the other in the lung. The results from this retrospective analysis and the review of other reports indicate that routine use of prophylactic spinal irradiation is not warranted in pineal region tumor, and the craniospinal irradiation is recommended in cases with high risk for subarachnoid seeding such as positive CSF cytology, surgical removal or biopsy.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.177-184
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• 1998

Purpose : Radiotherapy has been the mainstay of the treatment of brain metastases. We evaluated the response rate, survival and prognostic factors of patients with brain metastases treated with radiotherapy for palliative purpose. Materials and Methods : From January 1994 through April 1997, in all 42 patients, a retrospective analysis was undertaken. Of these, 33 patients received whole brain irradiation with 30Gy in 10 daily fractions with or without a boost of 10Gy in 5 daily fractions to the site of solitary lesion. Nine patients failed to complete the planned treatment Results : Of 33 patients who finished radiotherapy, complete and partial response were observed in $4(12\%)$ patients and $22(67\%)$ ones, respectively. Overall response rate was $79\%$ and median survival was 4 months. In univariate analysis, prognostic factors affecting survival were initial neurologic function class(p=0.0136), extracranial tumor activity(p=0.042), and response after radiotherapy(p=0.001). Conclusion : We confirmed that whole brain irradiation is the effective means for treating the patient with brain metastases. initial neurologic function class, extracranial tumor activity, and response alter radiotherapy were identified as prognostic factors affecting survival.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.73-91
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• 1994

The author used rabbits in order to examine the effect of Ga-As low power generating semiconductor laser on artificially produced injuries of experimental animals. Artificially produced injuries include surgical wound of 3mm length, 2mm depth in size on ventral skin surface of rabbit and buccal mucosa, and electrical injury formed on opposite side of skin and buccal mucosa by electrical cauterization of same length and depth, and chemical injury formed by FC(Formocresol) solution applied on the anterior dorsal part of tongue. And then, on the experimental group, Ga-As laser was irradiated beginning on the day after the wound formation and continued to irradiate every each other day for five minutes. After1, 3, 6, 9, 13th day, certain number of animals of control and experimental group were sacrified, and wound site tissue was excised to make samples and was observed under light microscope. The following is the conclusions after comparing the healing procedure of experimental and control group. The following results were obtained : 1. Inflammation was decreased more rapidly in the experimental group than the control group. 2. In the surgical, the electrical and the chemical injuries in the oral mucosa, re-epithelialization was completed more rapidly in the experimental group than the control group. In the electrical injury on the skin, re-epithelialization was completed about 6 days after wound formation on both groups. 3. In the electrical and the surgical injuries on the oral mucosa, granulation tissue formation started at 3 days after injury on both groups, but in the chemical injury, it was completed about 3 days faster in the control group than the experimental group. In the surgical wound on the skin, it was completed about 9 days after injury, but faster in the experimental group. In the electrical injury on the skin, it was faster in the control group than the experimental group. 4. In the electrical and the surgical injuries on the oral mucosa, fibrosis was started at 6~9 days after injury on both groups, but regeneration of connective tissue in the experimental group was observed much more than the control group. 5. When comparing the effect of wound healing on skin and oral mucosa of control and experimental group, granulation tissue formation and re-epithelialization in the oral mucosa was more vigorous. In conclusion, the difference of timing and the sequence of wound healing process(inflammation, re-epithelialization, granulation tissue formation, fibrosis) following Laser irradiation between control and experimental group was not observed, but the healing tissue was observed much more in the Laser irradiated group.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.192-199
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• 2024

In this study, carbamazepine (CBZ) imprinted starch/PVA-based biomaterials were prepared by the casting method and UV irradiation, and their physicochemical properties, CBZ adsorption ability, and release properties were investigated. The surface properties of the prepared biomaterials were characterized using FE-SEM, while the stability of CBZ under UV irradiation and the functional groups of the biomaterials were characterized using FT-IR analysis. The adsorption properties of CBZ on the biomaterials were evaluated by binding isotherm and Scatchard plot. Results indicate that CBZ imprinted biomaterials possess a specific binding site of CBZ. To evaluate the applicability of the transdermal drug delivery system, the release properties of CBZ from prepared biomaterials using various pH buffers and artificial skin at 36.5 ℃ were investigated. Results indicated that the CBZ release at high pH was faster than at low pH. In addition, CBZ was released continuously for 12 h in the artificial skin test. The drug release mechanism of CBZ followed a pseudo-Fickian diffusion mechanism in buffer solution, whereas the release from artificial skin exhibited a non-Fickian diffusion mechanism.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.2
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• pp.95-105
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• 2008

Purpose: To identify which is the best procedure in recycling autograft according to the resection & reconstruction type and recycling methods, and so when the recycling autograft is used in limb salvage surgery. Materials and Methods: We have treated fifty-eight patients (34 male, 24 female; age range 5 to 74 years, mean age 36.5 years), who had the malignant musculoskeletal tumors, with recycling autograft (47 patients with extracoporeal irradiation, 11 patients with pasteurization) from December 1995 to February 2006. The resection and reconstruction type was 3 cases with fragmentary, 8 intercalary, 23 rAPC (recycling-Autograft-Prosthesis composite), 18 osteoarticular, 5 total joint and 1 soft tissue (achilles tendon). The result was evaluated by the radiologic union at junctional site, the functional score by musculoskeletal tumor society score and complications according to the resection & reconstruction type and recycling methods. Results: The junctional union was obtained at 15.0 months in extracoporeal irradiation and 12.6 months in pasteurization. Also the mean radiologic union was shown at 6.0 months in fragmentary, 12.8 months in intercalary, 10 months in rAPC, 23.3 months in osteoarticular and 15.6 months in total joint. The functional score was 65.5% in fragmentary, 60.8% in intercalary, 62.8% in APC (except pelvis), 66.0% in osteoarticular and 66.6% in total joint. We have experienced 1 infection, 1 prutrusio acetabuli in pasteurization (18.1%) and other 22 complications (3 deep infections, 8 nonunions, 2 fractures, 2 epiphyseal problems, 5 joint instabilities, 2 local recurrence) in extracoporeal irradiation (46.8%). Also we have experienced 3 complications (3 nonunions) in intercalary (37.5%), 9 complications (4 nonunions, 1 deep infection, 1 periprosthetic fracture, 1 epiphyseal problem, 1 local recurrence, 1 protrusio acetabuli) in rAPC (50.0%), 6 complications (2 deep infections, 2 nonunions, 1 epiphyseal problem, 1 pathologic fracture) in osteoarticular (33.3%), 5 complications (5 joint instabilities) in total joint (100%) and 1 complication(1 local recurrence) in soft tissue (100%). Conclusion: In our experience, according to the resection & reconstruction type fragmentary and intercalary may have several advantages such as good radiologic and functional result and low rate of complication. And it seems that rAPC was available in case which have no sufficient residual bone stock. Also the pasteurization may have more advantages than that of the extracorporeal irradiation.