Local BMP-7 release from a PLGA scaffolding-matrix for the repair of osteochondral defects in rabbits

Jung, M.R.,Shim, I.K.,Chung, H.J.,Lee, H.R.,Park, Y.J.,Lee, M.C.,Yang, Y.I.,Do, S.H.,Lee, S.J. Elsevier Science Publishers 2012 Journal of controlled release Vol.162 No.3

The use of tissue engineering to repair large osteochondral defects has been impeded by the limited regenerative capacity of cartilage. Herein, we describe the local release of bone morphogenetic protein 7 (BMP-7) to stimulate the bone marrow-derived progenitors to repair osteochondral defects. BMP-7-releasing poly(d,l-lactide-co-glycolide) (PLGA) matrix was specially designed to retain the dual-function of local BMP-7 release and progenitor-scaffolding with its defect-fitting architecture. To optimize the release kinetics during the repair period, BMP-7/PLGA film was cast on the surface of a cylindrical PLGA matrix. The matrix demonstrated a release profile of BMP-7 in a sustained manner over 28days, maintaining its biological activity. The cylindrical PLGA matrices loaded with BMP-7 were implanted into the osteochondral defects (2mm in diameter, 3mm in depth) in rabbit knees. Histological observations revealed that neo-cartilage generation was completed in a well-integrated morphology with its surrounding normal cartilage and subchondral bone at 12weeks post-implantation. Partial degradation of the PLGA matrix during the repair period guided neo-cartilage formation, which verified the effective scaffolding function of the matrix. Regenerated cartilage in BMP-7-treated defects stained positive for type II collagen and glycosaminoglycan (GAG). Adjacent BMP-7-untreated defects were also repaired with cartilage regeneration, suggesting the effect of local BMP-7 release in the synovial fluid. The BMP-7-unloaded PLGA matrix demonstrated guided cartilage regeneration to a certain extent, whereas the adjacent defects without the matrix revealed only fibrous tissue infiltration. These results indicated that a strategy employing the combined functions of local BMP-7 release and the cell scaffolding of a PLGA matrix might be a potential modality for osteochondral repair.

Adaptive location of repaired blade for multi-axis milling

Wu, Baohai,Wang, Jian,Zhang, Ying,Luo, Ming Society for Computational Design and Engineering 2015 Journal of computational design and engineering Vol.2 No.4

Free-form blades are widely used in different industries, such as aero-engine and steam turbine. Blades that are damaged during service or have production deficiencies are usually replaced with new ones. This leads to the waste of expensive material and is not sustainable. However, material and costs can be saved by repairing of locally damaged blades or blades with localized production deficiencies. The blade needs to be further machined after welding process to reach the aerodynamic performance requirements. This paper outlines an adaptive location approach of repaired blade for model reconstruction and NC machining. Firstly, a mathematical model is established to describe the localization problem under constraints. Secondly, by solving the mathematical model, localization of repaired blade for NC machining can be obtained. Furthermore, a more flexible method based on the proposed mathematical model and the continuity of the deformation process is developed to realize a better localization. Thirdly, by rebuilding the model of the repaired blade and extracting repair error, optimized tool paths for NC machining is generated adaptively for each individual part. Finally, three examples are given to validate the proposed method.

Inguinal hernia repair in patients with liver cirrhosis accompanied by ascites

Young Hoe Hur,Jung Chul Kim,Dong Yi Kim,Shin Kon Kim,Chan Yong Park 대한외과학회 2011 Annals of Surgical Treatment and Research(ASRT) Vol.80 No.6

Purpose: We describe the clinical characteristics and assess the outcomes and stability of inguinal hernia repair under local anesthesia for patients with liver cirrhosis accompanied by ascites. Methods: We retrospectively reviewed the medical records of 22 patients with cirrhosis and ascites who underwent mesh plug hernia repair performed by a single surgeon from January 2002 to August 2009, and the clinical characteristics and outcomes of the patients were analyzed. Results: Twenty-two patients were included in the study. Fifteen (68.2%) were Child’s class B and seven (31.8%) were Child’s class C. Hernia repairs were successful without major complications or recurrence in all patients. Minor complications occurred in only three patients, consisting of two hematomas and one case of scrotal swelling. Complications were resolved spontaneously without the need for blood transfusion or reintervention. Thirteen patients died during follow-up (59.1%); eight of these patients died within 1 year after hernia repair. However, there was no 30-day postoperative mortality. Five of the eight patients who died were Child’s class B and the remaining three patients were Child’s class C. Deaths were all related to cirrhotic complications, and there was no operation-related mortality. Conclusion: Inguinal hernia repairs under local anesthesia in patients with cirrhosis accompanied by ascites were performed safely and effectively. Therefore, surgical repair is recommended even in patients with refractory ascites and poor hepatic function to prevent life-threatening complications or severe pain and improve quality of life.

선형 재생 부호 앙상블의 평균 복구 접속 비용

박진수(Jin Soo Park),김정현(Jung-Hyun Kim),박기현(Ki-Hyeon Park),송홍엽(Hong-Yeop Song) 한국통신학회 2014 韓國通信學會論文誌 Vol.39 No.11(네트워크)

본 논문에서는 임의의 선형 재생 부호 앙상블에 대하여 복구 대역폭(Repair bandwidth)과 접속 비용(Repair read cost)의 평균을 유도한다. 한 데이터가 여러 노드에 부호화 되어 분산 저장된 상황에서 하나의 노드가 소실될 경우, 이를 복구하기 위해 필요한 데이터 량을 복구 대역폭, 접속해야 하는 노드 수를 복구 접속 비용이라 한다. 이 때, 선형 재생 부호 앙상블은 데이터 심볼의 수 k와 패리티 심볼의 수 m, 그리고 그들의 차수 분포로 주어진다. 우리는 이러한 부호들이 시스터메틱(Systematic)이며 정확한 복구(Exact repair)를 수행하고 n=k+m개의 모든 저장소(Storages)들이 전부 연결되어 있는 상황을 가정한다. 본 논문의 결과는 파운틴 부호 등과 같이 위와 같은 파라미터들로 랜덤하게 만들어진 부호들에 바로 적용 가능하다. 최종 결과식은 평균 복구 접속 비용이 차수 분포와 n, k에 따라 결정됨을 보여준다. In this paper, we derive the average repair bandwidth and/or read cost for arbitrary repairable linear code ensembles. The repair bandwidth and read cost are the required amount of data and access number of nodes to restore a failed node, respectively. Here, the repairable linear code ensemble is given by such parameters as the number k of data symbols, the number m of parity symbols, and their degree distributions. We further assume that the code is systematic, and no other constraint is assumed, except possibly that the exact repair could be done by the parity check-sum relation with fully connected n=k+m storages. This enables one to apply the result of this paper directly to any randomly constructed codes with the above parameters, such as linear fountain codes. The final expression of the average repair read cost shows that it is highly dependent on the degree distribution of parity symbols, and also the values n and k.

Minimum Bandwidth Regenerating Codes Based on Cyclic VFR Codes

( Jing Wang ),( Shuxia Wang ),( Tiantian Wang ),( Xuefei Zhang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.7

In order to improve the reliability and repair efficiency of distributed storage systems, minimum bandwidth regenerating (MBR) codes based on cyclic variable fractional repetition (VFR) codes are constructed in this thesis, which can repair failed nodes accurately. Specifically, in order to consider the imbalance of data accessed by the users, cyclic VFR codes are constructed according to that data with different heat degrees are copied in different repetition degrees. Moreover, we divide the storage nodes into groups, and construct MBR codes based on cyclic VFR codes to improve the file download speed. Performance analysis and simulation results show that, the repair locality of a single node failure is always 2 when MBR codes based on cyclic VFR codes are adopted in distributed storage systems, which is obviously superior to the traditional MBR codes. Compared with RS codes and simple regenerating codes, the proposed MBR codes based on cyclic VFR codes have lower repair locality, repair complexity and bandwidth overhead, as well as higher repair efficiency. Moreover, relative to FR codes, the MBR codes based on cyclic VFR codes can be applicable to more storage systems.

Effects of Correction by Heating/Pressing on Mechanical Behavior of Steel Bridge Pier

Mikihito Hirohata,Takuya Morimoto,You-Chul Kim 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.1

A series of experiments was conducted in order to elucidate effects of correction by heating/pressing on mechanical behavior of steel bridge piers. Local buckling deformation of specimens due to loading considering the situation of an earthquake was corrected by heating/pressing, with or without water-cooling. Some out-of-plane deformations were inevitably left to avoid cracking in the welds. This geometric imperfection was defined as residual imperfection. After the correction, the same loading experiment was conducted. From the results, no deterioration was confirmed in mechanical properties of the steel even with water-cooling only if heating temperature was kept below A1 transformation temperature. Although it is ideal to have local buckling deformation repaired within the allowance of initial deflection in correction by heating/pressing, it was elucidated that making the residual imperfection mode opposite to local buckling mode was reasonable for guarantee of the maximum load of the corrected structure. A series of experiments was conducted in order to elucidate effects of correction by heating/pressing on mechanical behavior of steel bridge piers. Local buckling deformation of specimens due to loading considering the situation of an earthquake was corrected by heating/pressing, with or without water-cooling. Some out-of-plane deformations were inevitably left to avoid cracking in the welds. This geometric imperfection was defined as residual imperfection. After the correction, the same loading experiment was conducted. From the results, no deterioration was confirmed in mechanical properties of the steel even with water-cooling only if heating temperature was kept below A1 transformation temperature. Although it is ideal to have local buckling deformation repaired within the allowance of initial deflection in correction by heating/pressing, it was elucidated that making the residual imperfection mode opposite to local buckling mode was reasonable for guarantee of the maximum load of the corrected structure.

Real-Time Repairable Interpolation Scheme for CNC Tool Path Processing

Wei Fan,Chen-Han Lee,Ji-Hong Chen 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.12

G01 trajectory is widely-adopted for CNC machining. The piecewise linear trajectory is geometrically discontinuous, bringing about drastic fluctuation of feedrate and acceleration, and causing low machining efficiency and quality. Many methods of trajectory smoothing are developed and applied in CNC system. However some shortcomings exist when these methods were applied in CNC machining. In the existing methods, the following requirements are not satisfied simultaneously: not less than G2 continuity, confined chord error, shape preservation, interpolating G01 points, spatial applicability, real-time performance of algorithm, free geometric form. Considering various requirements of CNC machining, this work develops an interpolation scheme with local repairing function to deal with the possible shape deficiencies of trajectory. The resulting tool path has G2 continuity and is optimized in bending energy under shape-preserving and chord error constraints. Combining with jerk-limited feedrate scheduling, a real-time tool path processing strategy is developed. The simulation demonstrates the proposed method eliminates shape deficiencies, and has apparent advantage in the reduction of contour error, curvature, bending energy and machining time, compared with Zhao’s and Fan’s methods. The experiment demonstrates the advantages of the proposed algorithm in improving the quality of machined surface and machining efficiency, compared with previous methods.

DSR 기반의 무선 에드 혹 네트워크에서 계층적인 라우팅 캐쉬를 이용한 지역 경로 복구

한승진 ( Seung-jin Han ) 한국고등직업교육학회 2005 한국고등직업교육학회논문집 Vol.6 No.1

Compared with wired networks, wireless networks are usually limited bandwidth, QoS, and battery power, so that their routing protocols should have efficient routing protocols between mobile hosts. In Ad Hoc Networks, a connection frequently breaks due to the irregular movement of mobile hosts. When a link in DSR (Dynamic Source Routing) is broken, the upstream node of the broken link sends RERR message to the source node. In this paper, I propose an efficient route maintenance scheme using hierarchical routing caches. The proposed scheme, named as HDSR, applies to all nodes in DSR-based Ad Hoc networks. The HDSR scheme can efficiently recover some link breaks without relying on the existing DSR route maintenance scheme, thereby reducing the repair time and data packet transmission time. The simulation results show that the proposed scheme can reduce the repair time efficiently and thus, reduce the overall packet delivery time.

초고령 환자에서 국소마취를 이용한 서혜부 탈장교정술

김훈진(Hun Jin Kim),류희선(Hee Seon Ryu),허영회(Young Hoe Hur),김정철(Jung Chul Kim),김신곤(Shin Kon Kim),박찬용(Chan Yong Park) 대한외과학회 2009 Annals of Surgical Treatment and Research(ASRT) Vol.77 No.5

Purpose: We are to describe the clinical characteristics and treatment outcomes in patients aged between 80 and 89 years who underwent inguinal hernia repair under local anesthesia. Methods: We retrospectively reviewed the medical records of patients aged between 20 and 89 years who underwent tension free hernia repair under local anesthesia by a single surgeon between June 2001 and January 2009 and compared clinical characteristics and outcomes between octogenarians who were the eldest and sexagenarians whose incidence was the highest. Results: Of the 514 patients, the number of octogenarians was 52 (8.6%) and sexagenarians were 225 (35.0%). Body mass index (BMI) was 22.5 ㎏/㎡ in octogenarians and 23.7 ㎏/㎡ in sexagenarians (P=0.003). Underlying diseases were present in 67.3% of octogenarians and 73.5% of sexagenarians (P=0.238). The incidence of liver disease was significantly lower in the octogenarians (1.9% vs 15.7%, P=0.004). The proportion of patients who underwent local anesthesia was significantly higher among the octogenarians (94.5% vs 82.2%, P=0.014). Operative time and postoperative hospital stay had no significant difference between both groups. Postoperative complications developed in 4 (7.7%) of the octogenarians and in 18 (9.7%) of the sexagenarians. Scrotal swelling was developed most frequently and surgery-related mortality did not developed in both groups. Conclusion: If local anesthesia is used appropriately, inguinal hernia repair in octogenarians is a safe procedure as like in sexagenarians and may reduce the psychiatric burden related to complications for both surgeons and elderly patients.

일제강점기 초기 역사적 건조물 보존수리의 특징에 관한 연구

서동천(Seo, Dongchun) 대한건축학회 2018 대한건축학회논문집 Vol.34 No.1

The society for conservation of local historical properties in Korea originated in Japan. It was transplanted by Joseon Governor-General to represent their positions in the field of the conservations of the cultural properties. Also the society for conservation of local historic properties represented the positions of the provincial government office because the representatives of that societies were the chief of local government offices. At that time, the fundamental concept of the historical property conservations was not settled, so they accomplished the conservation activities as the necessary way for themselves. They often made a proposal about repairs for conservation of historical building and suggested a application for the national budget. And they contributed to carry out the repair works of the historical properties in the early Japanese colonial period. But they was usually used to invigorate the tourism and to publicize the regional characteristics through the historical properties. Although the societies were privately-managed as a matter of form, they were governmentally-managed as a matter of fact. It was the limits of the societies for conservation of local historical properties at that time.