Automated Bead Design Considering Production Constraints

B. Kronauer,N. Majic,M. Golle,H. Hoffmann,A. Albers 한국소성가공학회 2010 기타자료 Vol.2010 No.6

For design of stiff and lightweight sheet metal parts different construction methods are practicable. One important is weight neutral stiffness increasing using beads. Mostly empiric guidelines are used for designing bead structures until now. Alternatively rudiment simulation based methods for optimizing bead structures exist. But they do not consider production constraints such as formability or forming history. Users have to interpret optimizing results and have to transfer them into forming tools. Thus stiffness properties can be easily changed in a wrong way. Within the framework of a research project funded by the Deutsche Forschungsgemeinschaft a new method for automated design of bead structures considering production constraints, defined as ManuBeadOpt (Manufacturing based Bead Optimization), is developed. The methods substantial goal is linking forming simulation (based on inverse approach) and bead optimization to generate iteratively an optimal production-oriented bead structure. Therefore a forming tool based on the Nakazima-experiment for determining forming limit curves has been developed where punch is scaled on 400 mm diameter. Depending on this punch diameter a selected preformed area on pole of test pieces will be used for bead punching. Thereby specific strain allocations are possible, which accordingly affect the final test piece geometry. Afterwards the beaded area will be blanked and tested concerning stiffness behavior depending on bending, torsion and shear load cases. So relations between forming history, bead geometry, bead depth, stiffness, tool parameters, etc. will be identified. This knowledge is integrated in ManuBeadOpt for automatic evaluation of manufacturing. Tool, experimental and simulation results as well as the optimization method ManuBeadOpt will be shown.

키토산 비드지지체에서 주공극과 미세공극이 연골세포의 부착과 성장에 미치는 영향

박상준 ( Sang Jun Park ),김천호 ( Chun Ho Kim ) 한국조직공학과 재생의학회 2008 조직공학과 재생의학 Vol.5 No.4

The porous structure of scaffold is important parameter for cell and drug delivery. In this study, The chitosan bead scaffolds having open macropores interconnected with micropores were prepared from phase separation process and the effect of quenching rate on pore size of the beads was investigated. The morphology of the beads was analyzed by scanning electron microscopy(SEM). The addition of non-solvent in chitosan solution was to make the homogeneous micropores and improved interconnectivity between macropores without any surface skin layer. The macropore size of the beads was controlled to change of temperature of cooling medium. The macropore size of the new prepared chitosan bead scaffolds(1CS-RT70 and 10B-RT70) was the largest of the chitosan bead scaffolds fabricated from conventional method. Chondrocytes isolated from rabbit costal cartilage were cultured on the beads. Cellular viability and proliferation were assayed by cell counting kit- 8. Initial cell proliferation in the beads with micropores was higher than that in the beads without micropores. Cell attachment and distribution in the beads were also analyzed by SEM and Safrain-O staining after 14 days culture. The proliferation of chondrocytes were exhibited in only surface of the 1CS-LN2 and 10B-LN2 bead scaffolds but exhibited in both surface and center of the 1CS-RT70 and 10B-RT70 bead scaffolds. Therefore the new prepared chitosan bead scaffolds are more suitable for tissue engineering application.

구형화에 의한 커피 비드 제조와 품질특성에 알긴산과 칼슘의 비율 및 반응시간이 미치는 영향

서정희,양희완 한국식품조리과학회 2019 한국식품조리과학회지 Vol.35 No.2

Purpose: This study examined the factors influencing the preparation of coffee beads by spherification for a novel application of coffee. The factors were as follows; alginate-calcium ratio (R) and reaction time between the two reactants. Methods: Based on the fact that negatively-charged alginate molecules are bridged by calcium divalent cations (Ca2+) through electrostatic attractions and a calcium-alginate gel is formed, coffee beads were prepared at different R (0.38 to 1.13) and reaction times (30 to 210 sec). The texture and sensory attributes of the beads were then characterized. Results: At a relatively lower R, the sphericity and hardness of the beads increased with increasing R, showing that the alginate concentration was a critical factor for bead formation. Coffee beads formed at relatively higher R had lower cohesiveness and springiness. This was attributed to the densely cross-linking gel structure surrounding the bead surface that could block the inward diffusion of Ca2+. The phenomenon appeared to improve the sensory preference, presumably due to the loss of less coffee flavor components through the compact bead surface. The coffee beads prepared at R=0.63 showed an increase in sphericity and hardness with increasing reaction time, without any change in cohesiveness. This indicates that Ca2+ ions were used to form a Ca-alginate membrane around the bead surface to increase the gel strength, instead of further diffusing inward. The sensory evaluation showed that the textural properties related to gelation and to the density of the Ca-alginate membrane were the determining factors for preference. Conclusion: These results suggest that the R and reaction time in preparing coffee beads by spherification affect the textural and sensory properties of the coffee beads, which could be due to the possible changes in the structure of the Ca-alginate membrane. This study provides valuable basic information for the production of coffee beads.

Sourdough에서 분리된 유산균의 고농도 배양을 위한 중화제로서 Calcium Carbonate-Alginate Bead의 이용가능성 평가

정승원,이광근,김철우,이수한 한국산업식품공학회 2010 산업 식품공학 Vol.14 No.3

유산균을 고농도로 배양하기 위하여 CaCO3를 각각 15%와 20%씩 첨가하여 직경이 서로 다른 CaCO3-alginate beads를 제조한 후, lactic acid에 대한 CaCO3-alginate beads의 반응 특성과 완충효과를 관찰하였으며, lactic acid에 대하여 완충작용이 있는 CaCO3-alginate beads를 이용하여 S. thermophilus ST-Body 1과 L. amylovorus DU-21을 고농도 배양하여 직접투입식 starter를 제조하였다. 본 연구에서 제조된 CaCO3-alginate beads는 CaCO3, alginate 함량 및 수분 함유율이 beads에 일정하게 고루 분포되어 있으며, 일정한 밀도를 갖는 입자임을 알 수 있었다. 또한 lactic acid에 대한 beads의 반응은 표면으로부터 일어나기 시작하여 내부로 진행됨을 확인하였으며, CaCO3-alginate beads 양의 증가는 결국 lactic acid와 반응할 수 있는 CaCO3 표면적의 증가를 가져오게 되며, 단위시간당 lactic acid와 반응하는 CaCO3의 상대적 증가를 가져오기 때문에 CaCO3-alginate beads 양의 증가는 lactic acid 용액 내부의 중화작용의 증가를 가져온다는 것을 확인하였다. 즉, CaCO3-alginate beads의 직경이 작을수록, 내부의 CaCO3 함량이 높을수록, 단위 부피당 넓은 표면적과 높은 중화작용을 가지므로 CaCO3-alginate beads를 pH neutralizer로 이용하여 유산균을 배양할 경우에는 CaCO3 함량이 높고 직경이 작은 CaCO3-alginate beads의 이용이 유산균 배양에 효과적임을 알 수 있었다. CaCO3-alginate beads를 이용한 유산균의 고농도 배양 시, pH와 생균수와의 상관성과 선형관계를 단순회귀분석법(simple regression)을 이용하여 최소자승추정량(least square estimator; LSE)을 구하여 검증한 결과, 각 X의 회귀계수의 값은 통계적으로 유의한 결과(p<0.05, p<0.01)를 보였다. 또한 R2 값은 S. thermophilus ST-Body 1와 L. amylovorus DU-21의 경우, CaCO3-alginate beads 무첨가구와 첨가구에서 각각 0.6310, 0.7505, 0.7452, 0.7609이였다. 이는 pH가 균 증식에 다소나마 영향을 주는 것을 나타낸다. 고농도로 배양된 S. thermophilus ST-Body 1과 L. amylovorus DU-21 균주를 이용하여 직접투입식 starter를 제조한 결과, 동결건조 보호제로 15% glycerol을 이용하였을 때 각각 91.96±1.35%와 89.09±4.49%의 생존율을 보였다. 본 연구에서 확립된 기법은 probiotics 조제나 정장제 조제방법에 있어서도 공히 적용 가능하므로 미생물 세포의 이용기법으로 그 생존율과 발효에 연관되는 기능보존과 수반되는 여러 분야에 적용한다는 면에서 산업적으로 중요하다고 사료된다. Lab scale experiments were conducted in order to assess the applicability of CaCO3-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of CaCO3-alginate bead became higher. In batch process with CaCO3-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, CaCO3-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

백제 금제구슬의 형태 구분과 금순도 비교

김성곤,김은아,김규호 백제학회 2022 백제학보 Vol.- No.40

In this study, 1,067 gold beads excavated from 15 ruins in Baekje were classified intoⅠ, Ⅱ, and Ⅲ types according to the physical shape and the gold purity was compared. Type I identified in ruins of the Hanseong and Ungjin period was oval with 22 beads, and two holes were observed on one side. Type Ⅰ was divided into 3 groups according to the decoration of the gold plate. Ⅰ-A Type of 6 beads with gold plate only, Ⅰ-B Type of 7 beads with thin lines engraved on the gold plate, and Ⅰ-C Type of 9 beads with granulation on the gold plate. Type II identified in ruins of the Ungjin and Sabi period is 857 beads, which is a combination of two hemispherical gold plates with one hole. Type Ⅱ was divided into 2 groups according to their shape. The Round Ⅱ-A Type of 709 beads, and the flower shape beads Ⅱ-B Type of 148 beads. Type Ⅲ is confirmed from the remains of the Ungjin and Sabi periods, but many of them were excavated from the tomb of King Muryeong of Gongju. Aspherical Ⅲ-A Type with the small gold ring has 4 beads, Ⅲ-B Type with thin lines has 2 beads, and Ⅲ-C Type with granules decorations has 199 beads. In the comparison of gold purity according to shape, type I shows the characteristic of the various distribution of gold purity. Ⅰ-A Type is 15.1∼23.0K, Ⅰ-B Type is 15.8∼23.7K, andⅠ-C Type is 20.9∼21.3K. Type Ⅱ is close to pure gold, Ⅱ-A Type is 23.6∼23.8K, and Ⅱ-B Type is 23.8∼24.0K. Type Ⅲ shows a characteristic that the purity of gold increases from 20.0∼20.9K, Ⅲ-A Type to 22.9∼23.2, Ⅲ-B type, 23.0∼23.8K, and Ⅲ-C type. In summary, type I gold beads which are relatively low in the purity of gold, are found mainly in ruins presumed to be local power and aristocratic groups, and types II and III gold beads with high gold purity are mainly found in ruins related to the royal family of Ungjin and Sabi period. Therefore, it is presumed that the Baekje gold beads, which show the relationship between the shape and purity of gold a correlation according to period and local. 본 연구는 백제지역 15개 유적에서 출토된 금제구슬 1,067점을 형태에 따라 Ⅰ, Ⅱ, Ⅲ 유형으로 구분하고 이에 따른 금 순도를 비교하였다. 한성기와 웅진기 유적에서 확인되는 Ⅰ유형은 22점으로 타원형이고 한면에 두 개의 투공이 관찰된다. Ⅰ유형은 세부 특징에 따라 금판으로 구성된 Ⅰ-A형이 6점, 각목대가 둘러진Ⅰ-B형이 7점, 금판에 장식이 있는 Ⅰ-C형이 9점으로 구분하였다. 웅진기와 사비기의 주요 유적에서 확인되는 Ⅱ유형은 857점으로 투공이 한 개 있는 반구체 금판 2매를 결합한 형태이다. Ⅱ유형은 세부 특징에 따라구형(Ⅱ-A형) 709점과 화형(Ⅱ-B형) 148점으로 구분된다. 웅진기와 사비기 유적에서 확인되나 다수가 공주무령왕릉에서 출토된 Ⅲ유형은 205점으로 소환과 누금을 연접한 구슬이다. Ⅲ유형은 소환을 연접한 형태인Ⅲ-A형 4점, 소환에 각목문이 장식된 Ⅲ-B형 2점, 누금장식이 확인되는 Ⅲ-C형 199점으로 구분하였다. 형태에 따른 금 순도의 비교에서, Ⅰ유형은 금 순도가 다양하게 분포하는 특징을 보인다. Ⅰ-A형이 15.1~23.0 K, Ⅰ-B형이 15.8~23.7 K, Ⅰ-C형이 20.9~21.3 K이다. Ⅱ유형은 순금에 가까운 편이다. Ⅱ-A형이23.6~23.8 K, Ⅱ-B형이 23.8~24.0 K으로 확인된다. Ⅲ유형은 세부 유형에 따라 금 순도가 차이를 보인다. Ⅲ-A형이 20.0~20.9 K, Ⅲ-B형이 22.9~23.2 K, Ⅲ-C형이 23.0~23.8 K로 금 순도가 높아지는 특징을보인다. 이를 종합하면 상대적으로 금 순도가 낮은 금제구슬 Ⅰ유형은 지방재지 세력과 귀족 집단으로 추정되는 유적에서, 금 순도가 높은 금제구슬 Ⅱ, Ⅲ유형은 웅진기와 사비기의 왕실과 관련된 유적에서 주로 확인되는 것을 알 수 있다. 따라서 형태와 금 순도가 상관성을 보이는 백제 금제구슬은 시기와 지역에 따른 특성도 나타난다.

Sourdough에서 분리된 유산균의 고농도 배양을 위한 중화제로서 Calcium Carbonate-Alginate Bead의 이용가능성 평가

정승원 ( Seung Won Jung ),이광근 ( Kwang Geun Lee ),김철우 ( Cheol Woo Kim ),이수한 ( Su Han Lee ) 한국산업식품공학회 2010 산업 식품공학 Vol.14 No.3

유산균을 고농도로 배양하기 위하여 CaCO3를 각각 15%와 20%씩 첨가하여 직경이 서로 다른 CaCO3-alginate beads를 제조한 후, lactic acid에 대한 CaCO3-alginate beads의 반응 특성과 완충효과를 관찰하였으며, lactic acid에 대하여 완충작용이 있는 CaCO3-alginate beads를 이용하여 S. thermophilus ST-Body 1과 L. amylovorus DU-21을 고농도 배양하여 직접투입식 starter를 제조하였다. 본 연구에서 제조된 CaCO3-alginate beads는 CaCO3, alginate 함량 및 수분 함유율이 beads에 일정하게 고루 분포되어 있으며, 일정한 밀도를 갖는 입자임을 알 수 있었다. 또한 lactic acid에 대한 beads의 반응은 표면으로부터 일어나기 시작하여 내부로 진행됨을 확인하였으며, CaCO3-alginate beads 양의 증가는 결국 lactic acid와 반응할 수 있는 CaCO3 표면적의 증가를 가져오게 되며, 단위시간당 lactic acid와 반응하는 CaCO3의 상대적 증가를 가져오기 때문에 CaCO3-alginate beads 양의 증가는 lactic acid 용액 내부의 중화작용의 증가를 가져온다는 것을 확인하였다. 즉, CaCO3-alginate beads의 직경이 작을수록, 내부의 CaCO3 함량이 높을수록, 단위 부피당 넓은 표면적과 높은 중화작용을 가지므로 CaCO3-alginate beads를 pH neutralizer로 이용하여 유산균을 배양할 경우에는 CaCO3 함량이 높고 직경이 작은 CaCO3-alginate beads의 이용이 유산균 배양에 효과적임을 알 수 있었다. CaCO3-alginate beads를 이용한 유산균의 고농도 배양 시, pH와 생균수와의 상관성과 선형관계를 단순회귀분석법(simple regression)을 이용하여 최소자승추정량(least square estimator; LSE)을 구하여 검증한 결과, 각 X의 회귀계수의 값은 통계적으로 유의한 결과(p<0.05, p<0.01)를 보였다. 또한 R2 값은 S. thermophilus ST-Body 1와 L. amylovorus DU-21의 경우, CaCO3-alginate beads 무첨가구와 첨가구에서 각각 0.6310, 0.7505, 0.7452, 0.7609이였다. 이는 pH가 균 증식에 다소나마 영향을 주는 것을 나타낸다. 고농도로 배양된 S. thermophilus ST-Body 1과 L. amylovorus DU-21 균주를 이용하여 직접투입식 starter를 제조한 결과, 동결건조 보호제로 15% glycerol을 이용하였을 때 각각 91.96±1.35%와 89.09±4.49%의 생존율을 보였다. 본 연구에서 확립된 기법은 probiotics 조제나 정장제 조제방법에 있어서도 공히 적용 가능하므로 미생물 세포의 이용기법으로 그 생존율과 발효에 연관되는 기능보존과 수반되는 여러 분야에 적용한다는 면에서 산업적으로 중요하다고 사료된다. Lab scale experiments were conducted in order to assess the applicability of CaCO3-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of CaCO3-alginate bead became higher. In batch process with CaCO3-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, CaCO3-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

고정화 Aspergillus niger Bead를 이용한 포도당과 호박으로부터 구연산 생성

방병호 한국식품영양학회 2000 韓國食品營養學會誌 Vol.13 No.4

Aspergillus niger KCTC 6144 포자를 alginate bead로 고정화하여 호박배지(포도당 9%, 호박가루 1%, pH 6)를 이용하여 구연산 발효를 수행하였다. 고정화된 A. niger 포자가 bead 내에서 발아하여 균사가 bead를 뚫고 자라났으며 30℃에서 4일간 배양 후 그 크기는 2.0∼2.5㎜에서 6∼8㎜로 커졌다. 30℃에서 5일간 진탕배양(150rpm)으로, 50ml 호박 배지가 든 250ml 삼각 flask를 사용하여. 구연산 생성의 최적 발효 조건을 검토한 결과는 다음과 같다. 탄소원으로 포도당을 12%로 올렸을 때 구연산의 생성이 최고에 달하였고, 질소 및 무기질원으로 1%의 호박가루가 구연산 생성에 가장 알맞는 농도였다. 초기 pH는 6.0, bead의 수가 100개로 하였을 때 구연산 생성이 가장 좋았으며, 포토당 12%, 호박가루 1%로 한 최적 배양 조건에서, 5일만에 구연산이 23.5g/l로 최고로 생성되었다. The spore of Aspergillus niger KCTC-6144 was immobilized on alginate gel beads. When pumpkin powder was used with glucose for a medium of citric acid fermentation by Aspergillus niger beads, the beaded Aspergillus niger grew up inside the bead and mycelia penetrated through the pore of the bead membrane. The bead size became largely from 2.0∼2.5㎜ to 6∼8㎜ after growing at 30℃ for 4 days. Studies of optimum culture conditions on citric acid fermentation using Aspergillus niger beads on pumpkin medium (pumpkin powder 1% + glucose 9%, pH 6.0) were carried out in submerged cultures on 250ml Erlenmeyer flask. As a result, it was found that to reinforce 12% as carbon source was good for citric acid production and that 1% pumpkin powder was good as nitrogen and mineral source in orbital shaker (150rpm) at 30℃ for 5 days. The optimum initial pH on citric acid production was pH 6.0 and it was found that 100 beads of immobilized Aspergillus niger was adequate for citric acid production in a 250ml Erlenmeyer flask containing 50ml of pumpkin medium solution with orbital shaker at 30℃ for 5 days. We also found that maximal production of citric acid was 23.5g/ℓ at optimal condition (at 30℃ for 5 days, pH 6.0, and 100 beads and medium containing 1% pumpkin powder plus 12% glucose).

울진 덕천리 신라묘군 출토 구슬류의 특성 고찰

이민희,김규호 국립중앙박물관 2019 박물관보존과학 Vol.22 No.-

본 연구에서는 울진 덕천리 신라묘군에서 출토된 구슬류 80점에 대해 형태적 특징 관찰 및 화학적 조성분석을 실시하여 제작기법과 원료의 특성을 제시하고 이를 바탕으로 유구별 출토 양상을 살펴보고자 하였다. 울진 덕천리 신라묘군 출토 구슬류는 곡옥 1점과 관옥 1점, 환옥 78점으로 구별된다. 그 중 곡옥과 관옥, 환옥 3점은 광물제 구슬, 75점은 유리제 구슬로 확인되며 유리제 구슬은 대부분 유리 융액을 늘여서 제작된 것으로 추정된다. 조성특성을 유구별로 살펴보면, 상대적으로 상부에 위치하는 유구에서는 다양한 색상의 소다유리군이 확인되는데 비해 중부는 다양한 융제의 유리제 구슬이 출토되고 하부는 감청색 소다유리군이 주로 확인된다. 따라서 유구 위치에 따라 유리제 구슬의 양상이 다름이 확인된다. 또한 5~6C 초의 유구에서 집중적으로 구슬이 출토되어 6C 이전, 울진을 중심으로 구슬을 수용하고 부장했던 집단이 있었을 가능성을 시사하며 신라가 중앙집권화가 되어가는 6C 이후 해당 지역에서 구슬이 자취를 감추게 되는 특징을 보인다. This study investigated the formal characteristics and chemical compositions of eighty beads excavated from a Silla tomb complex at Deokcheon-ri, Uljin in order to reveal the methods of production and the characteristics of the raw materials involved, thereby illuminating characteristics of the relics from each tomb. The beads excavated from these Silla tombs include one curved bead, one tubular bead, and 78 globular beads. Among them, the curved and tubular beads and three globular beads were identified to be made of minerals, and the remaining 75 beads are made of glass. Most of the glass beads are thought to have been produced using the drawing technique. The characteristics of the beads were classified according to their site of excavation. The globular beads from Tomb No. 34 belong to the lead barium glass and potash glass groups, indicating that these beads were produced at a relatively earlier period in time. The glass beads excavated from the tombs in the northern portion of the complex differ in color and chemical composition from those in the southern portion, which indicates the character that each group of beads had different aspect according to site location. Considering that the excavated beads were mainly from fifth- and sixth-century tombs, it is likely that certain groups of people living around Uljin used and buried beads in their tombs. As the governance of Silla became more centralized in the sixth century, the use of beads for burial purpose appears to have come to an end in this region.

<여우구슬>과 성(性)불안의 극복

나지영 ( Na Ji-young ) 한국고전문학교육학회 2007 고전문학과 교육 Vol.14 No.-

This paper is to interpret < the glass beads of fox > in a psychoanalytical way. After analyzing the structure of < the glass beads of fox >, it is shown that < the glass beads of fox >can be read as a story of overcoming sexual anxiety. There are important features of < the glass beads of fox >. First, the main character of < the glass beads of fox > is always a boy. The boy is influenced by adults all the time, he is not yet able to make his own decision. He is still under control of parents and teacher. Second, The boy is forced to make a relationship with a fox. He kisses with the fox while the glass beads are coming and going between their mouths. This is very first sexual experiences to him. But he doesn't tell about the incident, he is avoiding to tell the truth to adults. He is scared, but pleased at the same time. Third, as time goes by, the boy gets thinner and paler. because of the fox. The teacher finds out about the fox, and instructs to the boy that he should swallow the glass beads of fox during the kiss. The teacher knows that this is the only way for the boy to survive. It means that if the boy wants to survive, he must kiss the fox once more, and swallow the beads. Fourth, The boy succeeds to swallow the beads, but fails to look up the sky. The teacher indicates to him that after swallowing the beads, the boy should look up the sky. But the boy can't look up the sky out of fear, instead he falls down on the ground. After he falls down with beads, he becomes a gifted geomancer. Therefore, he now has a job, and be able to take care of himself, not by his parents anymore. In conclusion, < the glass beads of fox > can be interpreted to the story of overcoming sexual anxiety. The boy experiences sexual anxiety. At first, he can't over come it, that's why he is almost killed. But he follows what the teacher indicates, and do swallow the beads. Despite of his falling down, he gets still extraordinary talent, and becomes a adult. He now is no longer under control of his parents. He can live his own life. It's because he overcomes sexual anxiety.

Novel fabrication of PCL porous beads for use as an injectable cell carrier system

Lim, Sung Mook,Lee, Hyo Jung,Oh, Se Heang,Kim, Jin Man,Lee, Jin Ho Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of Biomedical Materials Research Part B Vol. No.

<P>Injectable polycaprolactone (PCL) porous beads were fabricated for use as cell carriers by a novel isolated particle-melting method (for nonporous beads) and the following melt-molding particulate-leaching method (for porous beads). The prepared beads showed highly porous and uniform pore structures with almost the same surface and interior porosities (porosity, over 90%). The PCL porous beads (bead size, 400–550 μm) with different pore sizes (25–50 and 50–100 μm) were compared for their in vitro cell (human chondrocyte) growth behavior with the nonporous beads. The porous beads showed higher cell seeding density and growth than the nonporous beads. The pore size effect between the porous beads was not significant up to 7 days, but after that time the beads with pore sizes of 50–100 μm showed significantly higher cell growth than those of 25–50 μm. To evaluate the tissue compatibility of the PCL porous beads, the beads were dispersed, uniformly, in cold Pluronic F127 solution and injected into hairless mice, subcutaneously, in the gel state of Pluronic F127 at room temperature, leading to the homogeneous bead delivery. The histological findings confirmed that the PCL porous beads in Pluronic F127 gel are biocompatible: surrounding tissues gradually infiltrated into the porous beads for up to 4 weeks with little inflammatory response. The PCL porous beads with highly porous and uniform pore structures fabricated in this study can be widely applicable as cell carriers. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009</P>