• Journal of Chest Surgery
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• v.36 no.6
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• pp.404-410
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• 2003

Different treatment options are available according to the stage and duration of the empyema. Stage I empyema (exudate stage) is treated concurrently by the administration of appropriate antibiotics and chest tube drainage. Stage III empyema (organized stage) is considered for decortication through an open thoracotomy. However, the treatment of fibrinopurulent, stage II empyema remains controversial. Recently, debridement with the use of Video-Assisted Thoracoscopic Surgery (VATS) has been proposed for the treatment of stage II empyema. We analyzed and report our initial experience of 5 cases of stage II empyema, treated with the use of VATS. Material and Method: Between June 2001 and February 2002, 5 patients with fibrinopurulent empyema that did not respond to antibiotics, chest tube drainage or Percutaneous Catheter drainage (PCD), and instillation of fibrinolytic agent were treated by debridement and irrigation with the use of VATS. A CT scan was performed in all patients before the operation to confirm the diagnosis of loculated empyema and to detect additional lung parenchymal diseases. Result: All 5 patients underwent successful debridement and irrigation with the use of VATS and the chest tube was inserted properly. And no patients needed conversion to open thoracotomy. The ratio of sex was 4 : 1 (male : female), the mean age was 53 years old (range, 26~73 years), the mean operative time was 73.4 minutes (range, 52~95 minutes), the mean duration of postoperative chest tube placement was 12.4 days (range, 6~19 days), and the mean duration of postoperative hospital stay was 20.8 days (range, 10~36 days). In all patients, clinical symptoms such as pain and fever subsided and simple chest PA view revealed satisfactory lung expansion. No major postoperative complication was observed during the hospital course and no patient suffered from the recurrence of empyema in the follow-up period. Conclusion: We think that early operation with the use of VATS is safe and efficient for stage II empyema which did not respond to medical treatment(antibiotics and chest tube drainage), therefore, it can prevent stage II empyema from advancing to stage III, organized empyema.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.953-960
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• 2019

The Miller cycle is a diesel engine that has been developed in recent years that it can reduce NOx and improve fuel consumption by reducing the compression ratio through intake valve closing (IVC) time control. The Miller cycle can be divided into the early Miller method of closing the intake valve before the bottom dead center (BDC) and the late Miller method of closing the intake valve after the BDC. At low speeds, the late Miller method is advantageous as it can increase the volumetric efficiency; while at medium and high speeds, the early Miller method is advantageous because of the high internal temperature reduction effect due to the expansion of the intake air during the piston lowering from IVC to BDC. Therefore, in consideration of the ef ects of the early and late Miller methods, it is necessary to adopt the most suitable Miller method for the operating conditions. In this study, a two-stage turbo charge system was applied to four-stroke engines and the process of enhancing the Miller effect through a reduction of the intake and exhaust valve overlap as well as the valve change adjustment mechanism were considered. As a result, the ef ects of fuel consumption and Tmax reduction were confirmed by adopting the Miller cycle with a two-stage supercharge, a reduction of valve overlap, and an increase of suction valve lift.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.28-28
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• 2001

The objective of this study was to the effect on subsequent development of EGF present in defined medium during bovine 1)oocyte maturation or 2)embryo culture. The presence of EGF during IVM, irrespective of concentration(1, 10, 100ng/$m\ell$), stimulated cumulus expansion and significantly increased the proportion of oocytes attaining metaphaseII, the rate of cleavage, and develop to blastocyst. 1. In the group of EGF-added medium(1, 10, 100ng/$m\ell$), nuclear maturation rate for in vitro maturation was 91% to 92% but was not significantly higher than control group(87%). 2. For in vitro maturation, in the group of EGF-added medium(1, 10, 100ng/$m\ell$)the rate of cumulus cell expansion degree 2 ranged from 81% to 87%, which was significantly higher than the control group(medium with EGF not added). The rate of in vitro fertilization, developing to 2-to 4- cell stage, was 76% to 80%, which was also significantly higher(p<0.05)than control group(62%). 3. For in vitro maturation, in the group of EGF added in medium(1, 10, 100ng/$m\ell$)the development rate to blastocyst was 24.3% to 27%, which was significantly higher than control group(13.7%). The total cleavage rate in the group of EGF-added medium was 77% to 82%, which was higher than control group. 4. The development rate to blastocyst for 6 days of cultivation and the hatching blastocyst were 30.6% and 59.1%, respectively, in the group of 100ng/$m\ell$ of EGF, which were significantly higher(p<0.05)than control group(14.0% and 24%, respectively), The numbers of cells in blastocyst were 140.2 and 148, respectively, in 10ng/$m\ell$ and 100ng/$m\ell$ of EGF-added medium, which were higher than 108.5 in control group. 5. The development rate of in vitro fertilized embryos to blastocyst in 10ng/$m\ell$ of EGF-added medium co-cultured with somatic cell was 28%, which was significantly higher(p<0.05)than control group(11.8%). The numbers of cells in blastocyst were 141.6 for EGF-added medium and 145 for EGF+co-culture group, which were higher than control(101.6)and medium co-cultured with somatic cells(110.6). These results showed that in vitro maturation and fertilization, EGF was found a significant effect of increase of development rate to blastocyst and cell number.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.225-233
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• 2011

The volume change in concrete takes place with changes in temperature and water content immediately after concrete casting. In the early age stage, the thermal and drying shrinkages can cause cracks that are very crucial to the durability of concrete. It was reported that when the cement with lightly-burnt MgO powder was used, the shrinkage of concrete can be reduced. This study investigates fundamental properties of cement composites with lightly burnt MgO powder by performing various experiments. The stability test results verified that MgO powder in cement composites does not cause any abnormal expansion. Also, the hydrate product analysis results obtained from MgO cement paste showed that MgO powder reduces the shrinkage at the longterm ages. In addition, the cement composites containing the proper amount of MgO powder could improve compressive strength. Finally, the shrinkage reduction from using MgO powder can be optimized by increasing MgO replacement level and curing temperature.

• Knowledge Management Research
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• v.16 no.2
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• pp.1-27
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• 2015

This paper presents a knowledge-based view of platform-centered collaborations among multiple organizations. Studies of technological innovation and knowledge creation have broadened beyond their initial emphasis on internal development within an organization or simple exchange of ideas between two parties toward complex collaboration among many organizations at the level of platform-based knowledge ecosystems. Platforms serve as an interface between different groups of producers and consumers in a variety of multi-sided knowledge markets such as smartphone operating systems and video games industries. This study is an exploratory examination to offer theoretical understanding of how the organizational capabilities of platform leaders help expand a network of platform participants. The growth of platform participants is particularly important in the early stage of any platforms as the concept of network effects suggests that the platform with the largest number of participants will capture entire markets. Building upon organization studies and network economics theory on multisided markets, this paper focuses on the role of platform leaders in expanding platform-based collaboration. In our view, platform leaders develop varying levels of three organizational capabilities to discern quality of potential participants, to attract them to actually participate in collaboration, and to maintain long-term exchange relations in the ecosystem. We suggest that the capabilities of platform leaders will have a positive effect on the expansion of platform participants to secure network effects, and also examine several contextual factors that moderate the relationship between a platform leader's capacity and platform expansion.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.569-584
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• 1997

The present study assessed the effects of Rapid Maxillary Expansion on head posture and hyoid bone position. For this study, 32 Angle's class III patients - hellman 3c $\~$ adult stage, mean age 12y9m - were selected and divided into two groups, A,B according to craniocervical angulation. Craniocervical angulation Increased in Group A and decreased in Group B after the therapy. And 23 Angle's class I persons $\~$ same hellman stage, mean age 12y7m $\~$ were selected (or the control group. Cephalometric analysis of skeletal pattern, pharyngeal space, head posture, hyoid bone position was performed. The results were as follows, 1. Comparison of skeletal pattern and pharyngeal space 1) All two groups(A,B) had Mandibular plane inclined inferiorly and no pharyngeal space change was obseved after RME therapy 2) Skeletal pattern and pharyngeal space of Group A, B were normal before and after treatment. 2. Comparison of head posture 1) Craniocervical angulation of Group A was increased after treatment. That of Group B was decreased and mandibular plane was inclined inferiorly after treatment. 2) Before treatment, craniocervical inclination was normal in Group A but larger than normal in Group B. After treatment, all two groups(A, B) had normal craniocervical angulation. 3. Comparison of hyoid bone position 1) After treatment, long axis of hyoid in Group A, B was not changed. Antero- posteriorly, hyoid position was changed posteriorly in Group A but no change was founded in Group B after treatment. Vertically, hyoid bone position were not changed in two groups except increase in APHFH in Group A after treatment 2) Long axis of hyoid bone was normal in Group A, B before and after treatment. Anteroposteriorly, hyoid bone position was more anterior than Group B, C before treatment but all the position of two groups had normal position after treatment. Vertical position of hyoid bone was normal in all two groups before and after treatment.

• Journal of Embryo Transfer
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• v.23 no.3
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• pp.223-227
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• 2008

The cryopreservation of Hanwoo embryos has become an integral part of assisted reproduction in animal. The objective of this study was to assess the effect of The objectives of this study were: (1) to evaluate the influence of bovine embryo developmental stage on in vitro embryo development after freezing, (2) to study the efficiency compared with conventional freezed embryos at different embryo source. For conventional slow-freezing, day 7 or 8 expanded blastocysts were collected. The standard freezing medium was 1.8 M ethylene glycol (EG). Embryos were equilibrated in 1.8 Methylene glycol(EG) with 0.1 M sucrose in Dulbecco's phosphate-buffered saline (D-PBS) supplemented with 0.5% bovine serum albumin. Embryos were then loaded individually into 0.25 ml-straw and placed directly into cooling chamber of programmable freezer precooled to $-7^{\circ}C$, after 2 min, the straw was seeded, maintained at $-7^{\circ}C$ for 8 min, and then cooled to $-35^{\circ}C$ at $0.3^{\circ}C$/min, plunged and stored in liquid nitrogen for at least 3 days. For thawing, the straw containing embryos were warmed in air for 10 see and exposed to $37^{\circ}C$ water for 20 sec. Straws were then removed from $37^{\circ}C$ water. Rates of blastocyst survive and hatched were evaluated at 12 to 48h post-warming. The re-expansion and hatched rates of morula embryos were significantly lower than those obtained for blastocysts and expansion blastocysts (31.6%, 10.5% vs, 68.9%, 22.2% vs, 73.7%, 53.6%, respectively). No differences in re-expansion rates were found between in vivo and in vitro blastocysts. whereas hatched rates was significantly higher (51.2%) in vivo compared with in vitro embryos (18.6%). in conclusion, demonstrate that conventional freezing can be used successfully in cryopreservation of in vitro and in vivo bovine embryos, and that it might be considered for use in commercial programs and embryo preservation.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.633-647
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• 2018

Ramyeon is a wheat-food that has been mixed a dietary culture of China, Japan, American and Korea. Simultaneously it was the first convenience food that made of flour in Korea, which had been relatively few recipes until the early 1960's. To examine the changes of Ramyeon which has been consumed in large quantities since the late 1960s, this paper classified 1963~2012 into 6 periods. From political, economic, social, cultural and international perspectives we considered the changes of Ramyeon through the articles analysis of mass media(DongaIlbo, The KyunghyangShinmun, MBC news). The total number of articles was 3,823 with an average of 76.46/y. Each field was summarized as following sub-topics; In political(Election, North Korea), in economic(Price, Economy), in social(Promotion campaign for eating of flour, Incidents, Donation), in cultural(Consumption, Extreme situations, Nutrition) and in international field(Exporting). Each period was named according to the feature; Early stage, Expansion stage, Domestic growth stage, Overseas stage, Advanced stage, Transition stage. Ramyeon has changed in a closely relation with society for past 50 years.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.231-236
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• 2000

This study was conducted to examine the effects of exogenous gonadotropins (PMSG+hCG) and an antioxidant (cysteine) on in vitro maturation of bovine follicular oocytes. Cumulus-oocyte complexes (COCs) aspirated from 2 to 5 mm ovarian follicles were cultured for 22 to 24 hours in a modified bovine embryo culture medium (mBECM) supplemented with 3 mg/mL bovine serum albumin, to which PMSG (10 IU/mL) + hCG (10 IU/mL) and/or cysteine (0.6 mM) were added. When examined the expansion of cumulus ce1ls at the end of maturation culture, greater (p<0.05) expansion was found after addition of PMSG+hCG (79 to 96%) to mBECM than after no addition (0%), regardless of the presence or absence of cysteine in the medium. The addition of cysteine did not stimulate cumulus expansion, but a high proportion (92%) of expansion was achieved when COCs were cultured after the addition of PMSG+hCG and cysteine to the medium. No difference in the proportion of oocytes underwent germinal vesicle breakdown (initiation of maturation) was found after the addition of PMSG+hCG and/or cysteine to mBECM. However, nuclear maturation (development to the metaphase-II stage) of oocytes was significantly stimulated by the combined addition of PMSG+hCG and cysteine, compared with no addition. In conclusion, both exogenous gonadotropins and an antioxidant are important for nuclear maturation of bovine immature oocytes and these factors have a cell-specific stimulatory action.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.75-86
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• 2003

In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.