CONTROL OF BLISTER RUST OF TAIWAN RED PINE IN TAIWAN

Peng,Lin Feng,Chung Yi Tsai,Zuei Ching Chen 한국산림과학회 1985 한국산림과학회지 Vol.71 No.1

In 1966, the outbreak of a rust disease was discovered from the young plantation of Taiwan red pine (Pines taiwanensis Hay.) at the northeastern part of Taiwan Island. The plantation of about 2,000㏊ planted with 3-4 years old saplings is located on the mountain slopes of a valley of the upper stream of Ta-Chia River. The rust disease was first discovered sporadically from the narrow margin of plantation surrounding the pine nursery which was located at the center of valley. The disease spread rapidly and the total infected area in 1968 had been recorded for 186 ha. The rust fungus was first identified as Cronartium ribicola J.C. Fischer. The alternative hosts of this rust fungus, Ribes spp. were not recovered from the area of infectian sites nor from the area of 20Km radius from the infected site. Instead of Ribes host, Paeonia suffruticosa Andr. were planted in the nursery near by the pine nursery from 1966. It was thus identified the rust fungus as Cronartium flaccidum (Alb. et Schw.) Wint. The extensive control measures were practiced from 1968 and the eradication of infected saplings, shrubs and weeds of forest floors was given the first priority. In total, 111,852 trees infected were felled down from 1966 to 1971. All infected branches or parts of the trees were first wrapped with the vinyl film to prevent the dispersion of rust spores and then trees were felled down and finally were burnt at the site. Rest of pine trees of the whole plantation were sprayed with the fungicides; 0.2% Dithane Z-78 or 4-4 Bordeux mixture with addition of 1% Uspulun. Spraying of fungicides was carried out at least twice a month and continued to 1971. In 1973 and 1974, reforestation by some resistance tree species such as Pines armandi Fr., Taiwania, Cryptomeria, or Chamaecyparis, etc, were practiced. In total, 148,500 seedlings of tree species mentioned above were replaced the infected pine trees. Since the first outbreak of the disease in 1966, 20 years have been passed without any new outbreak of the rust disease by C. flaccidum in the same site or any other plantations in Taiwan. The control of the rust disease erupted in Taiwan red pine plantation in 1966 in thus concluded as very successful.

Computational Screening of Nanoporous Materials for Hexane and Heptane Isomer Separation

Chung, Yongchul G.,Bai, Peng,Haranczyk, Maciej,Leperi, Karson T.,Li, Peng,Zhang, Hongda,Wang, Timothy C.,Duerinck, Tim,You, Fengqi,Hupp, Joseph T.,Farha, Omar K.,Siepmann, J. Ilja,Snurr, Randall Q. American Chemical Society 2017 Chemistry of materials Vol.29 No.15

<P>Computational high-throughput screening was carried out to assess a large number of-experimentally reported metal-organic frameworks (MOFs) and zeolites for their utility in hexane isomer separation. Through the work, we identified many MOFs and zeolites with high selectivity (SL+M > 10) for the group of n-hexane, 2-methylpentane, and 3-methylpentane (linear and monobranched isomers) versus 2,2-dimethylbutane and 2,3-dimethylbutane (dibranched isomers). This group of selective sorbents includes VICDOC (Fe-2(BDP)(3)), a MOF with triangular pores that is known to exhibit high isomer selectivity and capacity. For three of these structures, the adsorption isotherms for a 10-component mixture of hexane and heptane isomers were calculated. Subsequent simulations of column breakthrough curves showed that the DEYVUA MOF exhibits a longer process cycle time than VICDOC MOF or MRE zeolite, which are previously reported, high-performing materials, illustrating the importance of capacity in designing MOFs for practical applications. Among the identified candidates, we synthesized and characterized a MOF in a new copper form with high predicted adsorbent capacity (q(L+M) > 1.2 mol/L) and moderately high selectivity (SL+M approximate to 10). Finally, we examined the role of pore shape in hexane isomer separations, especially of triangular-shaped pores. We show through the potential energy surface and three-dimensional siting analyses that linear alkanes do not populate the corners of narrow triangular channels and that structures with nontriangular pores can efficiently separate hexane isomers. Detailed thermodynamic analysis illustrates how differences in the free energy of adsorption contribute to shape selective separation in nanoporous materials.</P>

The role of Asia-Pacific organizations in maintaining regional security

Chien Peng Chung 한국국방연구원 2008 The Korean Journal of Defense Analysis Vol.20 No.2

There are two regular regional security organizations in Asia*the Shanghai Cooperation Organization (SCO) and ASEAN Regional Forum (ARF)-through which regional states are involved in managing security pertaining to Eurasia and the Asia-Pacific, respectively. Since 2001, Asia-Pacific Economic Cooperation (APEC) leaders' meetings have addressed aspects of economic security. Whereas the SCO seems well institutionalized and purposeful, the ARF appears weakly structured and ineffective. This is because, while member states of the SCO are generally trustful of one another and hold in common most security objectives, concerns, and norms in the organization, many member states of the ARF have uneasy relations among themselves and share few security objectives, concerns, and norms in the forum. Moreover, while the SCO represents priority multilateral foreign and security policy interests for the People's Republic of China (PRC) and Russia, its two most important constituents, the ARF represents a secondary or fall-back position for the bilateral-first foreign and security policy relations of its major players like Japan, United States, and the PRC.

Reconstruction and Rejection of Mismatched and Matched Disturbances for a Class of Multivariable Systems

Chao-Chung Peng,Chieh-Li Chen,Christopher Edwards 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

This study proposes a synthetic control strategy for the reconstruction and rejection of mismatched and matched unknown disturbances. For a nonlinear scalar system, a nonlinear proportional-integral (PI) control is developed for dealing with matched disturbances. Next, a 2nd order system subjected to both matched and mismatched disturbances is considered. By incorporating the idea of backstepping design and conventional sliding mode control (SMC), the mismatched disturbance can be transformed into a matched one with respect to a virtual control input, and therefore the matching condition is extended. An extension of the proposed control framework for a class of multi-input multi-output (MIMO) systems is further provided.

A retrospective review of correlative radiological assessment and surgical exploration for hilar cholangiocarcinoma

Darren Chua,Albert Low,Yexin Koh,Brian Goh,Peng Chung Cheow,Juinn Har Kam,Jin Yao Teo,Ek Khoon Tan,Alexander Chung,London Lucien Ooi,Chung Yip Chan,Ser Yee Lee 한국간담췌외과학회 2018 Annals of hepato-biliary-pancreatic surgery Vol.22 No.3

Backgrounds/Aims: Hilar cholangiocarcinomas (HCCAs) are tumors that involve the biliary confluence; at present, radical surgery offers the only chance of long-term survival, but this can be challenging given the complexity of the hilar anatomy. Blumgart and Jarnagin described a preoperative staging system that incorporates the effect of local tumor extent and its impact on adjacent structures and that has been demonstrated to correlate better with actual surgical resectability. The primary aim of this study is to describe the correlation between preoperative Blumgart-Jarnagin staging and its correlation with surgical resectability. Methods: Patients who underwent surgical resection for hilar cholangiocarcinoma at Singapore General Hospital between January 1, 2002, and January 1, 2013, were identified from a prospectively maintained institutional database. All patients were staged based on the criteria described by Blumgart and Jarnagin. Correlation with surgical resectability was then determined. Results: A total of 19 patients were identified. Overall resectability was 57.8% (n=11). Patients with Blumgart-Jarnagin stage T1 had the highest rates of respectability at 80%; patients with stage T2 and T3 disease had resectability rates of 25% and 40% respectively. Median overall survival was 13.6 months. Conclusions: The Blumgart-Jarnagin staging system is useful for predicting tumor respectability in HCCA.

A single institution experience with robotic and laparoscopic distal pancreatectomies

Shi Qing Lee,Tousif Kabir,Ye-Xin Koh,Jin-Yao Teo,Ser-Yee Lee,Juinn-Huar Kam,Peng-Chung Cheow,Prema Raj Jeyaraj,Pierce K. H. Chow,London L. Ooi,Alexander Y. F. Chung,Chung-Yip Chan,Brian K. P. Goh 한국간담췌외과학회 2020 Annals of hepato-biliary-pancreatic surgery Vol.24 No.3

Backgrounds/Aims: This study aims to describe our experience with minimally-invasive distal pancreatectomies, with emphasis on the comparison between robotic distal pancreatectomy (RDP) and laparoscopic distal pancreatectomy (LDP). Methods: Retrospective review of 102 consecutive RDP and LDP from 2006 to 2019 was performed. Results: There were 27 and 75 patients who underwent RDP and LDP, respectively. There were 12 (11.8%) open conversions and 16 (15.7%) patients had major (>grade 2) morbidities. Patients who underwent RDP had significantly higher rates of splenic preservation (44.4% vs. 13.3%, p=0.002), higher rates of splenic-vessel preservation (40.7% vs. 9.3%, p=0.001), higher median difficulty score (5 vs. 3, p=0.002) but longer operation time (385 vs. 245 minutes, p<0.001). The rate of open conversion tended to be lower with RDP (3.7% vs. 14.7%, p=0.175). Conclusions: In our institution practice, both RDP and LDP were safe and effective. The use of RDP appeared to be complementary to LDP, allowing us to perform more difficult procedures with comparable postoperative outcomes.

Outcome of minimally-invasive versus open pancreatectomies for solid pseudopapillary neoplasms of the pancreas: A 2:1 matched case-control study

Hwee Leong Tan,Ek Khoon Tan,Jin Yao Teo,Juinn Huar Kam,Ser Yee Lee,Peng Chung Cheow,Prema Raj Jeyaraj,Pierce K. Chow,Alexander Y. Chung,London L. Ooi,Chung Yip Chan,Brian K. P. Goh 한국간담췌외과학회 2019 Annals of hepato-biliary-pancreatic surgery Vol.23 No.3

Backgrounds/Aims: Solid pseudopapillary neoplasm (SPPN) is typically seen in young healthy females who would likely benefit from minimally-invasive pancreatectomy (MIP). A few comparative studies have suggested that MIP is associated with favorable outcomes when compared to the open approach for SPPN. This study aims to mitigate potential selection bias by performing a matched case-control study comparing MIP vs open pancreatectomy (OP) for SPPN. Methods: We performed a single-institution retrospective electronic chart review of all patients who underwent surgery for pathologically confirmed SPPN between 2000 and 2017. A 2:1 matched comparison using age, gender, tumor size and the type of pancreatectomy was performed between OP and MIP. Results: A total of 40 patients with a median age of 40.3 years (range 16.5-64.4) and female sex predominance (n=34, 85.0%) underwent surgery during the study period. Nine patients underwent MIP. Matched comparison between 18 OP and 9 MIP demonstrated that MIP was associated with a longer median operating time (305 vs 180 min, p=0.046) and shorter median postoperative stay (6 vs 9 days, p=0.015). There were no significant differences in intraoperative blood loss, blood transfusion requirements, postoperative morbidity (including postoperative pancreatic fistula) and mortality, resection margins, lymph node yield and long-term survival. Conclusions: MIP is a safe and viable option in the management of SPPN with the benefit of a shorter postoperative length of stay at the expense of a longer operation time. There was no significant difference in oncologic outcomes between both groups of patients.

Repeat liver resection versus salvage liver transplant for recurrent hepatocellular carcinoma: A propensity score-adjusted and -matched comparison analysis

Yuxin Guo,Ek-Khoon Tan,Nicholas L. Syn,Thinesh-Lee Krishnamoorthy,Chee-Kiat Tan,Reina Lim,Ser-Yee Lee,Chung-Yip Chan,Peng-Chung Cheow,Alexander Y. F. Chung,Prema Raj Jeyaraj,Brian K. P. Goh 한국간담췌외과학회 2019 Annals of hepato-biliary-pancreatic surgery Vol.23 No.4

Backgrounds/Aims: Repeat liver resection (RLR) and salvage liver transplantation (SLT) are viable treatment options for recurrent hepatocellular carcinoma (HCC). With possibly superior survival outcomes than RLR, SLT is however, limited by liver graft availability and poses increased perioperative morbidity. In this study, we seek to compare the outcomes of RLR and SLT for patients with recurrent HCC. Methods: Between 1999 and 2018, 94 and 16 consecutive patients who underwent RLR and SLT respectively were identified. Further retrospective subgroup analysis was conducted, comparing 16 RLR with 16 SLT patients via propensity-score matching. Results: After propensity-score adjusted analyses, SLT demonstrated inferior short-term perioperative outcomes than RLR, with increased major morbidity (57.8% vs 5.4 %, p=0.0001), reoperations (39.1% vs 0, p<0.0001), renal insufficiency (30.1% vs 3%, p=0.0071), bleeding (19.8% vs 2.2%, p=0.0289), prolonged intensive care unit stay (median=4 vs 0 days, p<0.0001) and hospital stay (median= 19.8 vs 7.1days, p<0.001). However, SLT showed significantly lower recurrence rate (15.4% versus 70.3%, p=0.0005) and 5-year cumulative incidence of recurrences (19.4% versus 68.4%, p=0.005). Propensity-matched subgroup analysis showed concordant findings. Conclusions: While SLT offers potentially reduced risks of recurrence and trended towards improved long-term survival outcomes relative to RLR, it has poorer short-term perioperative outcomes. Patient selection is prudent amidst organ shortages to maximise allocated resources and optimise patient outcomes.

Predictors of post-hepatectomy liver failure in patients undergoing extensive liver resections for hepatocellular carcinoma

Ken Min Chin,John Carson Allen,Jin Yao Teo,Juinn Huar Kam,Ek Khoon Tan,Yexin Koh,Kim Poh Brian Goh,Peng Chung Cheow,Prema Raj,Kah Hoe Pierce Chow,Yaw Fui Alexander Chung,London Lucien Ooi,Chung Yip Ch 한국간담췌외과학회 2018 Annals of hepato-biliary-pancreatic surgery Vol.22 No.3

Backgrounds/Aims: To determine the prevalence of post-hepatectomy liver failure/insufficiency (PHLF/I) in patients undergoing extensive hepatic resections for hepatocellular carcinoma (HCC) and to assess the predictive value of preoperative factors for post-hepatectomy liver failure or insufficiency (PHLF/I). Methods: A retrospective review of patients who underwent liver resections for HCC between 2001 and 2013 was conducted. Preoperative parameters were assessed and analyzed for their predictive value of PHLF/I. Definitions used included the 50-50, International Study Group of Liver Surgery (ISGLS) and Memorial Sloan Kettering Cancer Centre (MSKCC) criteria. Results: Among the 848 patients who underwent liver resections for HCC between 2001 and 2013, 157 underwent right hepatectomy (RH) and extended right hepatectomy (ERH). The prevalence of PHLF/I was 7%, 41% and 28% based on the 50-50, ISGLS and MSKCC criteria, respectively. There were no significant differences in PHLF/I between RH and ERH. Model for End-Stage Liver Disease (MELD) score and bilirubin were the strongest independent predictors of PHLF/I based on the 50-50 and ISGLS/MSKCC criteria, respectively. Predictive models were developed for each of the criteria with multiple logistic regression. Conclusions: MELD score, bilirubin, alpha-fetoprotein and platelet count showed significant predictive value for PHLF/I (all p<0.05). A composite score based on these factors serves as guideline for physicians to better select patients undergoing extensive resections to minimize PHLF.

Outcomes of salvage liver transplant for recurrent hepatocellular carcinoma

Yuxin Guo,Ek-Khoon Tan,Thinesh-Lee Krishnamoorthy,Chee-Kiat Tan,Ban-Hock Tan,Thuan-Tong Tan,Ser-Yee Lee,Chung-Yip Chan,Peng-Chung Cheow,Alexander Y. F. Chung,Prema Raj Jeyaraj,Brian K. P. Goh 한국간담췌외과학회 2019 Annals of hepato-biliary-pancreatic surgery Vol.23 No.1

Backgrounds/Aims: Salvage liver transplantation (SLT) is a therapeutic strategy for recurrent hepatocellular carcinoma (HCC). However, it remains controversial with compromised survival outcomes and increased perioperative morbidity compared to primary liver transplant (PLT). In the present work, we describe our institution’s experience on SLT by comparing outcomes of SLT to PLT for HCCs. Methods: Retrospective analysis was conducted for 49 transplant patients from 2006-2017. A comparative analysis was carried out between 14 SLT patients and 35 PLT patients. Results: SLT patients demonstrated significantly shorter time to recurrence than PLT patients (median=5.5 versus 23 months, p<0.001) with a trend towards increased perioperative major morbidity (42.9% versus 37%, p=0.711), inferior 5-year overall survival (61% versus 75%, p=0.345) and inferior 5-year recurrence-free survival (57% versus 72%, p=0.263). However, overall survival from the point of primary resection over a 10-year period showed no statistical difference between the 2 groups (SLT=60% versus PLT=61%, p=0.685). Conclusions: SLT is a viable treatment strategy for HCCs. However, it exhibited poorer short-term perioperative and oncologic outcomes than PLT. SLT requires better patient selection with liver donor grafts for optimization of resource allocation in this era of organ shortage. Considering the worldwide shortages in liver grafts, it is hypothesized that optimization of a salvage transplant strategy may improve resource allocation and reap optimal patient outcomes.