• Journal of Gastric Cancer
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• v.8 no.1
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• pp.20-26
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• 2008

Purpose: Pylorus-preserving gastrectomy (PPG), which retains pyloric ring and gastric function, has been accepted as a function-preserving procedure for early gastric cancer for the prevention of postgastrectomy syndrome. This study was compared laparoscopy-assisted pylorus-preerving gastrectomy (LAPPG) with laparoscopy-assisted distal gastrectomy with Billroth-I reconstruction (LADGB I). Materials and Methods: Between November 2006 and September 2007, 39 patients with early gastric cancer underwent laparoscopy-assisted gastrectomy in the Department of Surgery at Korea Cancer Center Hospital. 9 of these patients underwent LAPPG and 18 underwent LADGBI. When LAPPG was underwent, we preserved the pyloric branch, hepatic branch, and celiac branch of the vagus nerve, the infrapyloric artery, and the right gastric artery and performed D1+$\beta$ lymphadenectomy to the exclusion of suprapyloric lymph node dissection. The distal stomach was resected while retaining a $2.5{\sim}3.0\;cm$ pyloric cuff and maintaining a $3.0{\sim}4.0\;cm$ distal margin for the resection. Results: The mean age for patients who underwent LAPPG and LADGBI were $59.9{\pm}9.4$ year-old and $64.1{\pm}10.0$ year-old, respectively. The sex ratio was 1.3 : 1.0 (male 5, female 4) in the LAPPG group and 2.6 : 1.0 (male 13, female 5) in the LADGBI group. Mean total number of dissected lymph nodes ($28.3{\pm}11.9$ versus $28.1{\pm}8.9$), operation time ($269.0{\pm}34.4$ versus $236.3{\pm}39.6$ minutes), estimated blood loss ($191.1{\pm}85.7$ versus $218.3{\pm}150.6\;ml$), time to first flatus ($3.6{\pm}0.9$ versus $3.5{\pm}0.8$ days), time to start of diet ($5.1{\pm}0.9$ versus $5.1{\pm}1.7$ days), and postoperative hospital stay ($10.1{\pm}4.0$ versus $9.2{\pm}3.0$ days) were not found significant differences (P>0.05). The postoperative complications were 1 patient with gastric stasis and 1 patient with wound seroma in LAPPG group and 1 patient with left lateral segment infarct of liver in the LADGB I group. Conclusion: Patients treated by LAPPG showed a comparable quality of surgical operation compared with those treated by LADGBI. LAPPG has an important role in the surgical management of early gastric cancer in terms of quality of postoperative life. Randomized controlled studies should be undertaken to analyze the optimal survival and long-term outcomes of this operative procedure.

• Advances in nano research
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• v.13 no.5
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• pp.437-451
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• 2022

Synthesis approaches usually affect the physical and chemical properties of ferrites. This helps ferrite materials to design them for desired applications. Some of these methods are mechanical milling, ultrasonic method, micro-emulsion, co-precipitation, thermal decomposition, hydrothermal, microwave-assisted, sol-gel, etc. These methods are extensively reviewed by taking example of ZnFe₂O₄. These methods also affect the microstructure and local structure of ferrite which ultimately affect the physical and chemical properties of ferrites. Various spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Ultra Violet-Visible spectroscopy, Mossbauer spectroscopy, extended x-ray absorption fine structure, and electron paramagnetic resonance are found helpful to reveal this information. Hence, the basic principle and the usefulness of these techniques to find out appropriate information in ZnFe₂O₄ nanoparticles is elaborated in this review.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.3
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• pp.193-202
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• 2008

Objective: To evaluate efficacy of assisted hatching by laser (AHL) and acidified Tyrode solution (AHA) in selected groups of IVF-ET patients who have a poor prognosis. Methods: From February 2006 to September 2006, total of 328 IVF-ET cycles with advanced female age (${\geq}38$ years), recurrent implantation failure (${\geq}3$ cycles), thick zona (${\geq}17{\mu}m$), and/or poor quality of embryo were randomly divided into assisted hatching by acidified Tyrode solution (AHA, n=180) and the assisted hatching using the ZILOS-tk laser (AHL, n=148) groups. Clinical outcomes were analyzed and compared between AHA and AHL group based on the patient characteristics. Results: In all AHL and AHA group, there were no significant differences in pregnancy (42.6%, 63/148 vs. 33.3%, 60/180) and implantation rates (17.4%, 82/470 vs. 16.0%, 89/556) However, in advanced female age group (Group 1), pregnancy (37.0%, 20/54 vs. 18.7%, 14/75) and implantation rates (14.4%, 23/160 vs. 7.1%, 15/210) in AHL group were significantly (p<0.05) higher than those of AHA, although there was no difference in patient parameters of both groups. And, the clinical outcome of groups with recurrent implantation failure (Group 2), thick zona pellucida (Group 3) and poor quality embryo (Group 4) were improved in AHL compared to those of AHA: 43.8% (21/48) and 31.6% (25/79) in Group 2, 43.8% (32/73) and 34.1% (28/82) in Group 3, 25.0% (7/28) and 14.6% (6/41) in Group 4, but no significance. Conclusion: The AHL improved the pregnancy and implantation rates in patients with advanced female age and recurrent implantation failure when compared to outcomes achieved from AHA. Therefore, this AHL technique may be a efficient and safe method for patients with poor prognosis.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.405-413
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• 2011

It was proposed that technologies derived from CAD-CAM and computed tomography may be useful for flapless implant treatment procedures. The aims of this study were to validate the reliability of this concept in a prospective 12-month clinical study. Twelve patients with fully edentulous areas in their mandibles were included in this study. A total of 71 implants were inserted in interforaminal regions by use of a CAD/CAM drill template($NobelGuide^{TM}$), specially designed for flapless implant surgery. To assess the degree of pain and discomfort, the patients were examined at 2 days and 1 week after surgery. Patient satisfaction and implant functionality were further evaluated at follow-up intervals of 1, 3, 6, and 12 months postoperatively. One implant failed early in 1 patient. All of the other implants were in a good functional state throughout the study. The mean marginal bone loss after 1 year of follow-up was 0.3 mm (SD, 0.1) at center, 0.5 mm (SD, 0.1) at canine and 0.7 mm (SD, 0.2) at distal fixtures, respectively. Statistically, there was not significant differences among each sites(P>.05)The mean ISQ change after 1 year of follow-up was -1.05 (SD, 2.76) at center, -0.85 (SD, 2.59) at canine and -1.27 (SD, 2.18) at distal fixtures, respectively. This prospective pilot study showed that the use of CAD/CAM technology and flapless implant surgery may be considered reliable for fully edentulous mandible of patients.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.294-298
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• 1999

Background: Video-assisted thoracoscopic surgery(VATS) has been established as a new method for treatment of spontaneous pneumothorax. We compared the clinical results of VATS with those of thoracotomy performed during the recent 5 years. Material and Method: We analyzed 126 patients whose medical records were available among the 154 patients who underwent operations for spontaneous pneumothorax from 1992 to 1996. The mean age was 27.1 years(15 to 75 years). 87 patients were operated on by VATS(Group A) and the other 39 by thoracotomy(Group B). The mean follow-up period was 14.7 months. Result: The operation time was shorter in group A than in group B(90.6${\pm}$38.6minutes: 117.2${\pm}$58.9minutes, p<0.05). The duration of postoperative hospital stay was shorter in group A than in group B(6.7${\pm}$4.2: 9.4${\pm}$3.3 days, p<0.05). The amount of analgesics(nalbuphin HCl, ketoprofen) used postoperatively were 2.4${\pm}$2.8 ampules in group A, which is less than the 6.5${\pm}$5.6 ampules in group B(p<0.05). The number of staples used in group A was smaller(2.7${\pm}$1.3 in group A, 1.76${\pm}$1.1 in group B, p<0.05). The duration of chest tube indwelling(4.3${\pm}$4.0 days in group A, and 5.6${\pm}$3.0 days in group B, NS), the recurrence rate(13.8% in group A, 2.6% in group B, NS), and the duration of air leakage(1.3${\pm}$3.3 days in group A, and 1.0${\pm}$2.5days in group B, NS) were not statistically different between the two groups. Conclusion: The application of VATS for the treatment of spontaneous pneumothorax has brought in better clinical results(shorter operation time, shorter hospital stay, less pain, and better cosmetic merits) than the thoracotomy without increasing any morbidity. However no advantages in recurrence rates and duration of postoperative air leakages are revealed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.430-430
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• 2012

The surface recombination velocity of the silicon solar cell could be reduced by passivation with insulating layers such as $SiO_2$, SiNx, $Al_2O_3$, a-Si. Especially, the aluminium oxide has advantages over other materials at rear surface, because negative fixed charge via Al vacancy has an additional back surface field effect (BSF). It can increase the lifetime of the hole carrier in p-type silicon. The aluminium oxide thin film layer is usually deposited by atomic layer deposition (ALD) technique, which is expensive and has low deposition rate. In this study, ICP-assisted reactive magnetron sputtering technique was adopted to overcome drawbacks of ALD technique. In addition, it has been known that by annealing aluminium oxide layer in nitrogen atmosphere, the negative fixed charge effect could be further improved. By using ICP-assisted reactive magnetron sputtering technique, oxygen to nitrogen ratio could be precisely controlled. Fabricated aluminium oxy-nitride (AlON) layer on silicon wafers were analyzed by x-ray photoelectron spectroscopy (XPS) to investigate the atomic concentration ratio and chemical states. The electrical properties of Al/($Al_2O_3$ or $SiO_2/Al_2O_3$)/Si (MIS) devices were characterized by the C-V measurement technique using HP 4284A. The detailed characteristics of the AlON passivation layer will be shown and discussed.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.296-301
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• 2009

An inductively coupled plasma assisted atomic layer deposition(ICP-ALD) system has been constructed for the deposition of ZnO thin films, and various experiments of ZnO thin films on p-type Si(100) substrates have been carried out to find the self-limiting reaction conditions for the ICP-ALD system under non-plasma circumstances. Diethyl zinc[$Zn(C_2H_5)_2$, DEZn] was used as the zinc precursor, $H_2O$ as the oxidant, and Ar as the carrier and purge gas. At the substrate temperature of $150^{\circ}C$, atomic layer deposition conditions based on self-limiting surface reaction were successfully obtained by series of experiments through the variation of exposure times for DEZn, $H_2O$, and Ar. ZnO deposition was repeated at different substrate temperatures of $90{\sim}210^{\circ}C$. As a result, the thermal process window(ALD window) for ZnO thin films was observed to be $110{\sim}190^{\circ}C$ and the average growth rate was measured to be constant of 0.29 nm/cycle. Properties of the film's microstructure and composition(Zn, O, etc.) were also studied. As the substrate temperature increases, the crystallinity was improved and ZnO(002) peak became dominant. The films deposited at all temperatures were high purity, and the films deposited at high temperatures had the composition ratio between Zn and O closer to one of a stable hexagonal wurtzite structure.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.78-94
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• 2005

Purpose. The purpose of this study was to compare the effects of various surface treatments by measuring resonance frequency and histomorphometric analyses. Material and methods. In 5 adult dogs, the mandibular premolar were extracted. Six months later, 30 screw titanium implants (Dentium Co., Seoul, Korea) 6mm in length and 3.4mm in diameter, were placed in the mandibles of 5 dogs. Implants were divided into five groups following to surface treatment methods ; Group 1 is machined controls, Group 2 is sandblasted with large grit and acid-etched (SLA), Group 3 is anodized (Autoelectric Co., Korea, 660Hz, Duty10), Group 4 is hydroxyapatite(HA) coated by ion beam assisted deposition(E-beam), Group 5 is hydroxyapatite(HA) coated with Sol-gel coating process. Resonance frequency was measured implant placement immediately, and 3, 6 weeks and 10 weeks of healing perods. With the animal subject's sacrifice 10 weeks after implantation, implants were removed on bloc and histologic and computer-based histomorphometric analyses were performed. Histomorphometric analysis involved quantification of the entire bone to metal contact around the implants. Statistical analyses were performed using the SPSS for Windows (ver. 9.0 SPSS Inc.) Statistical differences were considered significant at P<0.05. Results. The results were as follows : 1) In five groups, mean value of resonance frequency analysis(RFA) were highest in group 5 (Sol-gel implant) at implantation and those of group 4 (E-beam)was highest at 10 weeks . but there was no correlation between surface treatments and RFA. 2) In all surface treatment groups, the RFA values of implants decreased until 3 weeks and increased to 10 weeks. 3) The percentage of direct bone-to-implant contact (BIC) had statistical significance between five groups in cancellous bone, (P<0.05) the percentage of bone density inside the thread had no statistical significance between five groups. (P>0.05) 4) There was a significant difference between cortical bone and cancellous bone in BIC. (P<0.05) and bone density. (P<0.05) 5) There was a correlation between the RFA value of implants at 10 weeks and BIC in cancellous bone, and between the RFA value of implants at 10 weeks and bone density in cortical bone. (P<0.05). Conclusions. These results indicate that surface treatment does not affect the implant stability in case of good bone quality.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.235-240
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• 2014

Ethylene glycol (EG) has been successfully used as a cryoprotectant for vitrification of mammalian embryos (including human embryos) due to its low formula weight and high permeation into cells compared with other cryoprotectants, including propylene glycol (PROH). Cryopreservation is able to store the surplus pre-embryos for freezing and furthermore thawing and transfer in a subsequent cycle. This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Female ICR mice (6~8 weeks old) were induced to superovulate by sequential intraperitoneal injection of 5 IU PMSG and 5 IU hCG 48 h apart. Mouse embryos were collected according to its developmental stage after the injection of hCG. Embryos were cryopreserved not only during cryoprotectant step (1~4 step) but also in a variety of media (HTF, IVF medium, D-PBS) and cell stage. The results were as follows : There is no clear advantage in these freezing media of rapid method, but 4 cell and 8 cell of slow method (2, 3 and 4 step) have advantage in D-PBS. The development of embryos according to cell stage become greater in 8 cell stage. In the treatment steps of cryopreservation, the development of embryo to blastocyst was similar among rapid method, but the development of 4 cell and 8 cell embryos to blastocyst according to slow method was better than rapid method.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.154-155
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• 2012

The promise of nano-crystalites (nc) as a technological material, for applications including display backplane, and solar cells, may ultimately depend on tailoring their behavior through doping and crystallinity. Impurities can strongly modify electronic and optical properties of bulk and nc semiconductors. Highly doped dopant also effect structural properties (both grain size, crystal fraction) of nc-Si thin film. As discussed in several literatures, P atoms or radicals have the tendency to reside on the surface of nc. The P-radical segregation on the nano-grain surfaces that called self-purification may reduce the possibility of new nucleation because of the five-coordination of P. In addition, the P doping levels of ${\sim}2{\times}10^{21}\;at/cm^3$ is the solubility limitation of P in Si; the solubility of nc thin film should be smaller. Therefore, the non-activated P tends to segregate on the grain boundaries and the surface of nc. These mechanisms could prevent new nucleation on the existing grain surface. Therefore, most researches shown that highly doped nc-thin film by using conventional PECVD deposition system tended to have low crystallinity, where the formation energy of nucleation should be higher than the nc surface in the intrinsic materials. If the deposition technology that can make highly doped and simultaneously highly crystallized nc at low temperature, it can lead processes of next generation flexible devices. Recently, we are developing a novel CVD technology with a neutral particle beam (NPB) source, named as neutral beam assisted CVD (NBaCVD), which controls the energy of incident neutral particles in the range of 1~300eV in order to enhance the atomic activation and crystalline of thin films at low temperatures. During the formation of the nc-/pm-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. In the case of phosphorous doped Si thin films, the doping efficiency also increased as increasing the reflector bias (i.e. increasing NPB energy). At 330V of reflector bias, activation energy of the doped nc-Si thin film reduced as low as 0.001 eV. This means dopants are fully occupied as substitutional site, even though the Si thin film has nano-sized grain structure. And activated dopant concentration is recorded as high as up to 1020 #/$cm^3$ at very low process temperature (＜ $80^{\circ}C$) process without any post annealing. Theoretical solubility for the higher dopant concentration in Si thin film for order of 1020 #/$cm^3$ can be done only high temperature process or post annealing over $650^{\circ}C$. In general, as decreasing the grain size, the dopant binding energy increases as ratio of 1 of diameter of grain and the dopant hardly be activated. The highly doped nc-Si thin film by low-temperature NBaCVD process had smaller average grain size under 10 nm (measured by GIWAXS, GISAXS and TEM analysis), but achieved very higher activation of phosphorous dopant; NB energy sufficiently transports its energy to doping and crystallization even though without supplying additional thermal energy. TEM image shows that incubation layer does not formed between nc-Si film and SiO2 under later and highly crystallized nc-Si film is constructed with uniformly distributed nano-grains in polymorphous tissues. The nucleation should be start at the first layer on the SiO2 later, but it hardly growth to be cone-shaped micro-size grains. The nc-grain evenly embedded pm-Si thin film can be formatted by competition of the nucleation and the crystal growing, which depend on the NPB energies. In the evaluation of the light soaking degradation of photoconductivity, while conventional intrinsic and n-type doped a-Si thin films appeared typical degradation of photoconductivity, all of the nc-Si thin films processed by the NBaCVD show only a few % of degradation of it. From FTIR and RAMAN spectra, the energetic hydrogen NB atoms passivate nano-grain boundaries during the NBaCVD process because of the high diffusivity and chemical potential of hydrogen atoms.