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Assessing the Influence of Quiescence Eggs on the Dynamics of mosquito <i>Aedes aegypti</i>

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Applied Mathematics 2014年第17期5卷 2696-2711页

作者： hyun mo yang UNICAMP IMECC DMA Pra&#231 a Sérgio Buarque de Holanda Campinas Brazil

The anthropophilic and peridomestic female Aedes aegypti bites humans to suck blood to maturate fertilized eggs, which are laid in appropriate recipients (breeding sites). These eggs can hatch in contact with water releasing larvae, or can be stored in a dormant state (quiescence), which last for extended periods. Taking into account this ability of eggs of A. aegypti mosquitoes, mathematical model is developed taking into account four successive quiescence stages. The analysis of the model shows that the ability of the eggs surviving in dormant state in adverse abiotic conditions, depending on the model parameters, can increase the fitness of mosquito population;in other words, the capacity of the mosquitoes generating offsprings is increased.

关键词： Compartmental modeling Basic Offspring Number Stability Analysis Fitness Seasonality

The Assessment of the Arising of Food Allergy among Antiacid Users Using Mathematical model

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Applied Mathematics 2012年第3期3卷 293-307页

作者： hyun mo yang* Ariana Campos yang Keity Souza Santos Clovis Eduardo Galvao Fabio Fernandes morato Castro UNICAMP-IMECC-DMA Praca Sergio Buarque de HolandaCampinasBrazil Division of Allergy Clinics Hospital of FM-USPSao PauloBrazil

The first case of a new food allergy, an anaphylactic reaction to Manioc (Manihot esculenta or Manihot utilissima), also called cassava and tapioca, was described in 2001. Cassava is a tuber widely consumed in Brazil, which has been consumed by native Indians, i.e., more than 500 years ago, so why are the first cases just emerging now? We address this question by developing a mathematical model considering the fact that proton pump inhibitors (PPIs) for digestive disorders maintain the cassava allergen intact due to the elevation in pH of gastric juice, thereby facilitating its presentation to the immune system. The model assumed the mass action law including saturation to describe the recruitment of PPIs users, and Hill function to describe the sensitization of immune system by the allergens and the acquisition of full food allergy. Analytical results were obtained from the model, and numerical simulations were done. The estimated period of time elapsed since the introduction of antiacids before the diagnosis of food allergy was 15 years. The food allergy may become a public health problem, if PPIs are being used indiscriminately and irregularly. The results obtained from the analysis of the model suggest that the use of nonprescription antiacids, like PPIs, may be recommended or approved by the physician in order to avoid the rising of food allergy.

关键词： Deterministic model Sensitization of Immune System Cassava Allergens Proton Pump Inhibitors Public Health

An Optimal Control Approach to HIV Immunology

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Applied Mathematics 2015年第6期6卷 1115-1130页

作者： Edilson F. Arruda Claudia M. Dias Camila V. de Magalhã es Dayse H. Pastore Roberto C. A. Thomé hyun mo yang Instituto Alberto Luiz Coimbra de Pó s Graduaç ã o e Pesquisa de Engenharia Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Instituto Multidisciplinar Universidade Federal Rural do Rio de Janeiro Nova Igua&ccedil u Brazil Departamento de Matemá tica Centro Federal de Educa&ccedil ã o Tecnoló gica Celso Suckow da Fonseca Rio de Janeiro Brazil Departamento de Matemá tica Aplicada Universidade Estadual de Campinas Campinas Brazil

This paper introduces a mathematical model which describes the dynamics of the spread of HIV in the human body. This model is comprised of a system of ordinary differential equations that involve susceptible cells, infected cells, HIV, immune cells and immune active cells. The distinguishing feature in the proposed model with respect to other models in the literature is that it takes into account cells that represent two distinct mechanisms of the immune system in the defense against HIV: the non-HIV-activated cells and the HIV-activated cells. With a view at minimizing the side effects of a treatment that employs a drug combination designed to attack the HIV at various stages of its life cycle, we introduce control variables that represent the infected patient’s medication. The optimal control rule that prescribes the medication for a given time period is obtained by means of Pontryagin’s Maximum Principle.

关键词： HIV Mathematical modelling Optimal Control Pontryagin’s Maximum Principle

Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

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World Journal of Gastrointestinal Oncology 2024年第1期16卷 51-60页

作者： Ga Hee Kim Yeong Chan Lee Tae Jun Kim Sung Noh Hong Dong Kyung Chang Young-Ho Kim Dong-Hoon yang Chang mo moon Kyunga Kim hyun Gun Kim Eun-Ran Kim Division of Gastroenterology Department of Internal MedicineAsan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Department of Digital Health Samsung Advanced Institute for Health Science and TechnologySungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineEwha Womans UniversitySeoul 07985South Korea Biomedical Statistics Center Samsung Medical CenterSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineSeoul 04401South Korea

BACKGROUND The incidence of colorectal cancer(CRC)and preinvasive CRC(e.g.,early colon cancer and advanced adenoma)is gradually increasing in several countries.AIM To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in Korea.METHODS This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC,and assess the numbers of diagnostic colonoscopies and colonoscopic polypectomies.Colonoscopy-related complications by age group were also determined.RESULTS The incidence of CRC showed a rapid increase,then decreased after 2012 in the 50-75 year-age group.During the study period,the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of age.Since 2009,the increase has been rapid,showing a pattern similar to the increase in colonoscopies.The rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after 2007.The rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of age.CONCLUSION The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies performed.As the risk of colonoscopy-related hospitalization and death is high in the elderly,if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75,colonoscopy-related complications can be reduced for those aged 76 years or over.

关键词： Colorectal cancer Preinvasive colorectal cancer Colorectal polypectomy Colonoscopy

Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1639-1650页

作者： Yong Wang Wei Wang Joo hyun Park Wangzhong Mu Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education&Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081China Department of Materials Science and Engineering KTH Royal Institute of TechnologySE-10044StockholmSweden Department of Chemical Engineering Northeast Electric Power UniversityJilin 132012China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Korea Engineering Materials Division of Materials ScienceDepartment of Engineering Science and MathematicsLuleå University of Technology97187 LuleåSweden

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

关键词： high-entropy alloy non-metallic inclusion agglomeration thermodynamics alloying

Evolution of nonmetallic inclusions in 80-t 9CrmoCoB large-scale ingots during electroslag remelting process

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1525-1539页

作者： Shengchao Duan Min Joo Lee Yao Su Wangzhong Mu Dong Soo Kim Joo hyun Park School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Rep.of Korea Department of Materials Science and Engineering KTH Royal Institute of TechnologyBrinellvägen 23Stockholm 10044Sweden Department of Engineering Science and Mathematics Division of Materials ScienceLuleåUniversity of Technology97187 LuleåSweden Casting&Forging Business Unit Nuclear Business GroupDoosan EnerbilityChangwon 51711Rep.of Korea

In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrmoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR furnace.The main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS core.The Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification processes.Therefore,inclusions can act as nucleation sites for carbide layer precipitation.The ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted ingot.The M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy results.The substitution of Cr with W,Fe,or/and mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)carbide.Therefore,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)mo_(4.6)C_(6),and Cr_(16)Fe_(5)mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)carbide.The Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid inclusion.The increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

关键词： nonmetallic inclusion heat-resistant steel electroslag remelting M_(23)C_(6) carbide MnS inclusion supersaturation degree

Extensive complex thoracoabdominal aortic aneurysm salvaged by surgical graft providing landing zone for endovascular graft:A case report

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World Journal of Clinical Cases 2022年第15期10卷 5005-5011页

作者： Albert Youngwoo Jang Pyung Chun Oh Jin mo Kang Chul hyun Park Woong Chol Kang Department of Cardiology Gachon University Gil Medical CenterIncheon 1198South Korea Department of Internal Medicine Gil Medical CenterGachon Cardiovascular Research InstituteGachon University College of MedicineIncheon 1198South Korea Division of Vascular Surgery Gachon University Gil Medical CenterIncheon 1198South Korea Department of Thoracic and Cardiovascular Surgery Gachon University Gil Medical CenterIncheon 1198South Korea Division of Cardiology Gil Medical CenterGachon University of Medicine and ScienceIncheon 1198South Korea

BACKGROUND Surgical repair of complex abdominal aortic aneurysm is associated with a higher perioperative mortality and morbidity.The advent of endovascular aortic repair(EVAR)has reduced perioperative complications,although the utilization of such techniques is limited by lesion characteristics,such as involvement of the visceral or renal arteries(RA)and/or presence of a sealing zone.CASE SUMMARY A 60-year-old male presented with a Crawford type IV complex thoracoabdominal aortic aneurysm(CAAA)starting directly distal to the diaphragm extending to both common iliac arteries(CIAs).The CAAA consist of a proximal and distal aneurysmal sac separated by a 1 cm-healthy zone in the infrarenal level.Due to the poor performance of the patient and the expansive disease,we planned a stepwise-combined surgery and EVAR to minimize invasiveness.A branched graft was implanted after surgical debranching of the visceral and RA.Since the patient had renal and liver injury after surgery,the second stage EVAR was performed 10 mo later.The stent graft was implanted from the distal portion of surgical branched graft to both CIAs during EVAR.The patient has been uneventful for 5-years after discharge and is being followed in the outpatient clinic.CONCLUSION The current case demonstrates that the surgical graft can provide a landing zone for second stage EVAR to avoid aggressive surgery in patients with poor performance with a long hostile CAAA.

关键词： Complex thoracoabdominal aortic aneurysm Abdominal aortic aneurysm surgery Endovascular aortic repair Common iliac artery aneurysm Case report

Endoscopic retrograde cholangiopancreatography in pancreatic and biliary tract disease in Korean children

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World Journal of Gastroenterology 2010年第4期16卷 490-495页

作者： Joo Young Jang Chong hyun Yoon Kyung mo Kim Department of Pediatrics Asan Medical Center Children's HospitalUniversity of Ulsan College of MedicineSeoul 138-736South Korea Department of Pediatrics Ajou University School of MedicineSuwon 443-721South Korea Department of Pediatric Radiology Asan Medical Center Children's HospitalUniversity of Ulsan College of MedicineSeoul 138-736South Korea Department of Pediatrics Asan Medical Center Children’s HospitalUniversity of Ulsan College of MedicineSeoul 138-736South Korea

AIM:To assess the indications,findings,therapeutic procedures,safety,and complications of endoscopic retrograde cholangiopancreatography(ERCP) performed in Korean children.METHODS:The demographic characteristics,indications for ERCP,findings,therapeutic procedures,and complications of 122 pediatric patients who underwent 245 ERCPs in the Asan Medical Center between June 1994 and March 2008 were investigated.RESULTS:The mean age of the 122 patients was 8.0 ± 4.2 years.Indications were biliary pathology in 78(64.0%),pancreatic pathology in 43(35.2%),and chronic abdominal pain in one.Biliary indications included choledochal cysts in 40,choledocholithiasis in 24,suspected sclerosing cholangitis in 8,trauma in 2,and other conditions in 4.Pancreatic indications includedacute pancreatitis in 7,acute recurrent pancreatitis in 11,chronic pancreatitis in 20,trauma in 3,and pancreatic mass in 2.Of the 245 ERCPs,success rate was 98.4% and 190(77.6%) were for therapeutic purposes,including endoscopic nasal drainage(51.8%),biliary sphincterotomy(38.0%),pancreatic sphincterotomy(23.3%),stent insertion(15.1%),stone extraction(18.8%),and balloon dilatation(11.0%).Complications were postERCP pancreatitis in 16(6.5%),ileus in 23(9.4%),hemorrhage in 2(0.8%),perforation in 2(0.8%),sepsis in 1(0.4%),and impacted basket in 1(0.4%).There were no procedure-related deaths,and most complications improved under supportive care.CONCLUSION:This study showed that there is a high incidence of choledochal cyst and diagnostic and therapeutic ERCP for the management of various biliary and pancreatic diseases was safe and effective in Korean children.

关键词： Endoscopic retrograde cholangiopancreatography Pancreatic diseases Biliary tract diseases Choledochal cyst Pancreatitis Pediatrics

Early extrahepatic recurrence as a pivotal factor for survival after hepatocellular carcinoma resection:A 15-year observational study

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World Journal of Gastroenterology 2022年第36期28卷 5351-5363页

作者： Jae hyun Yoon Sung Kyu Choi Sung Bum Cho Hee Joon Kim yang Seok Ko Chung Hwan Jun Department of Gastroenterology and Hepatology Chonnam National University Hospital and College of MedicineGwangju 61469South Korea Department of Gastroenterology and Hepatology Hwasun Chonnam National University Hospital and College of MedicineHwasun 58128South Korea Department of Surgery Chonnam National University Hospital and College of MedicineGwangju 61469South Korea Department of Surgery Hwasun Chonnam National University Hospital and College of MedicineHwasun 58128South Korea Department of Internal Medicine Mokpo Hankook HospitalMokpo 58643South Korea

BACKGROUND Surgical resection is one of the most widely used modalities for the treatment of hepatocellular carcinoma(HCC).Early extrahepatic recurrence(EHR)of HCC after surgical resection is considered to be closely associated with poor prognosis.However,data regarding risk factors and survival outcomes of early EHR after surgical resection remain scarce.AIM To investigate the clinical features and risk factors of early EHR and elucidate its association with survival outcomes.METHODS From January 2004 to December 2019,we enrolled treatment-naïve patients who were≥18 years and underwent surgical resection for HCC in two tertiary academic centers.After excluding patients with tumor types other than HCC and/or ineligible data,this retrospective study finally included 779 patients.Surgical resection of HCC was performed according to the physicians’decisions and the EHR was diagnosed based on contrast-enhanced computed tomography or magnetic resonance imaging,and pathologic confirmation was performed in selected patients.Multivariate Cox regression analysis was performed to identify the variables associated with EHR.RESULTS Early EHR within 2 years after surgery was diagnosed in 9.5%of patients during a median followup period of 4.4 years.The recurrence-free survival period was 5.2 mo,and the median time to EHR was 8.8 mo in patients with early EHR.In 52.7%of patients with early EHR,EHR occurred as the first recurrence of HCC after surgical resection.On multivariate analysis,serum albumin100 U/L,surgical margin involvement,venous and/or lymphatic involvement,satellite nodules,tumor necrosis detected by pathology,tumor size≥7 cm,and macrovascular invasion were determined as risk factors associated with early EHR.After sub-categorizing the patients according to the number of risk factors,the rates of both EHR and survival showed a significant correlation with the risk of early EHR.Furthermore,multivariate analysis revealed that early EHR was associated with substantially worse survi

关键词： Early extrahepatic recurrence Hepatocellular carcinoma Prognosis Surgery Survival