检索结果-南通市图书馆

Comparative study of chitosan/fibroin–hydroxyapatite and collagen membranes for guided bone regeneration in rat calvarial defects: micro-computed tomography analysis

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2014年第2期6卷 87-93页

作者： jae Min Song Sang Hun Shin Yong Deok Kim jae Yeol Lee Young jae Baek Sang Yong yoon Hong sung Kim Department of Oral and Maxillofacial Surgery School of Dentistry Pusan National University Yangsan Korea Department of Biomaterial Science Pusan National University Miryang Korea

This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD）（P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.

关键词： chitosan/fibroin-hydroxyapatite collagen membrane guided bone regeneration micro-computed tomography rat calva rial defect

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

在线全文

学校读者我要写书评

暂无评论

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 ***,data regarding risk factors and survival outcomes of early EHR after surgical resection remain *** To investigate the clinical features and risk factors of early EHR and elucidate its association with survival *** 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 *** excluding patients with tumor types other than HCC and/or ineligible data,this retrospective study finally included 779 *** 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 *** Cox regression analysis was performed to identify the variables associated with *** Early EHR within 2 years after surgery was diagnosed in 9.5%of patients during a median followup period of 4.4 *** recurrence-free survival period was 5.2 mo,and the median time to EHR was 8.8 mo in patients with early *** 52.7%of patients with early EHR,EHR occurred as the first recurrence of HCC after surgical *** 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 *** 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 ***,multivariate analysis revealed that early E

关键词： Early extrahepatic recurrence Hepatocellular carcinoma Prognosis Surgery Survival

A macroscopic constitutive model of shape memory alloy considering cyclic effects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 755-764页

作者： ZHOU Bo yoon sung-Ho College of Pipeline and Civil Engineering China University of Petroleum School of Mechanical Engineering Kumoh National Institute of Technology

This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (SMA) under cyclic loading. The progressive increase of residual strain with the increased cycle number in such materials is assumed to be a consequence of the progressive increase of residual stress-induced martensitic volume fraction upon the cyclic effects. The progressive decrease of phase transformation critical stresses with the increased cycle number in such materials is assumed to be a result from the progressive increase of phase transformation critical temperatures upon the cyclic effects. A cyclic evolution equation is supposed to describe the influences of cycle effects on the material properties of the SMA under cyclic loading. A phase transformation equation expressing the phase transformation behaviors of the SMA under cyclic loading is established based on the differential relationship between martensitic volume fraction and the free energy increment of phase transformation. A mechanical constitutive equation predicting the mechanical characteristics of the SMA under cyclic loading is developed on the basis of thermodynamics and continuum mechanics. The cyclic evolution equation, phase transformation equation, and mechanical constitutive equation together compose the presented macroscopic constitutive model considering cyclic effects. Results of the numerical simulations illustrate that it can well reproduce the superelastic hysteretic behaviors of the SMA under cyclic loading.

关键词： shape memory alloy cyclic effect cyclic evolution equation phase transformation equation mechanical constitutive equation

Variations in dynamic recrystallization behavior and mechanical properties of AZ31 alloy with extrusion temperature

在线全文

学校读者我要写书评

暂无评论

镁合金学报(英文) 2023年第7期11卷 2351-2365页

作者： jae Won Cha sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

This study investigates the effects of extrusion temperature on the dynamic recrystallization(DRX)behavior of a Mg-3Al-1Zn-0.3Mn(AZ31,wt%)alloy during hot extrusion and on the microstructural characteristics and mechanical properties of materials extruded at 350 and 450℃.An increase in the extrusion temperature causes a decrease in the amount of strain energy accumulated in the material during extrusion,because of promoted activation of pyramidalslip and dynamic *** reduced strain energy weakens the DRX behavior during extrusion,which eventually results in a decrease in the area fraction of recrystallized grains of the extruded *** material extruded at 450℃has coarser grains and a stronger basal fiber texture than that extruded at 350℃.As the extrusion temperature increases from 350 to 450℃,the tensile yield strength(TYS)of the extruded material increases from 191.8 to 201.5 MPa,whereas its compressive yield strength(CYS)decreases from 122.5 to 111.0 MPa;consequently,its tension-compression yield stress ratio(CYS/TYS)decreases from 0.64 to *** increase in the TYS is attributed mainly to the stronger texture hardening and strain hardening effects of the extruded material,and the decrease in the CYS is attributed to the reduced twinning stress resulting from grain coarsening and texture *** microstructural and textural evolutions of the materials during extrusion and the deformation and hardening mechanisms of the extruded materials are discussed in detail.

关键词： Mg-Al-Zn alloy Extrusion Dynamic recrystallization Microstructure Yield asymmetry

Adsorption properties of polycarboxylate ether-based superplasticizer on cement particles and their resultant dispersion

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2022年第4期16卷 506-514页

作者： Jinyoung yoon Byoung Il CHOI jae Hong KIM Department of Structural Engineering Research Korea Institute of Civil Engineering and Building Technology(KICT)Goyang 10223Republic of Korea System Safety Research Department Korea Shipbuilding and Offshore EngineeringSeongnam 13591Republic of Korea Department of Civil and Environmental Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea

The cement dispersion performance of a polycarboxylate(PCE)-based superplasticizer is highly related to their adsorption behaviors as a function of *** study evaluated effects of PCEs on rheological properties of cementitious ***,characteristics of PCEs were characterized via permeation chromatography(GPC)and Fourier-transform infrared spectrometry(FT-IR).The adsorption behavior of single and blended PCEs on cementitious composites was identified using total organic carbon analyzer(TOC).Based on the measurement of PCE adsorption,the changes of rheological properties of cementitious materials as well as the number of dispersed cement particles were characterized using a rheometer and laser spectroscopy,*** experimental results support the systematic mechanism of PCE adsorption,cement dispersion,and the decrease in viscosity of cementitious materials.

关键词： adsorption polycarboxylate superplasticizer rheology dispersion

The beneficial impacts of splanchnic vasoactive agents on hepatic functional recovery in massive hepatectomy porcine model

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary Surgery and Nutrition 2021年第3期10卷 325-336页

作者： Hye-sung Jo jae Hyun Han yoon Young Choi Jin-I Seok Young-In yoon Dong-Sik Kim Division of HBP Surgery and Liver Transplantation Department of SurgeryKorea University College of MedicineSeoulRepublic of Korea Department of Surgery St.Vincent’s HospitalCollege of MedicineThe Catholic University of KoreaSeoulRepublic of Korea Department of Biomedical Science Korea University College of Medicine Graduate SchoolSeoulRepublic of Korea Division of Hepatobiliary Surgery and Liver Transplantation Department of SurgeryAsan Medical CenterUniversity of Ulsan College of MedicineSeoulRepublic of Korea

Background:Excessive portal pressure after massive hepatectomy can cause hepatic sinusoidal injury and have deleterious impacts on hepatic functional recovery,contributing to developing post-hepatectomy liver *** study aimed to assess the effects of splanchnic vasoactive agents on hepatic functional recovery and regeneration while clarifying the underlying mechanism,using a 70%hepatectomy porcine ***:Eighteen pigs undergoing 70%hepatectomy were involved in this study and divided into three groups:control(n=6),terlipressin(n=6),and octreotide(n=6).Terlipressin(0.5 mg)and octreotide(0.2 mg)were administered 3 times a day for each group with the first dose starting just before surgery until the 7th postoperative day,at which time the surviving pigs were *** the period,portal pressure,liver weight,biochemical analysis,histological injury score,and molecular markers were evaluated and compared between ***:The 7-day survival rates in the octreotide,terlipressin,and control groups were 100%,83.3%,and 66.7%,*** portal pressures decreased in both terlipressin and octreotide groups than the control group at 30 minutes,1 hour and 6 hours after *** amount of regeneration measured by liver weight to body weight ratio at the time of sacrifice in the terlipressin group was smaller than that in the control group(117%vs.129%,P=0.03).Serum aspartate aminotransferase(AST)and total bilirubin levels at 1 and 6 hours after hepatectomy and prothrombin time/international normalized ratio(PT/INR)at 6 hours after hepatectomy were significantly improved in the terlipressin and octreotide groups compared to the control *** endothelin-1(ET-1)was significantly lower in the terlipressin group than that in the control group 6 hours after hepatectomy(P<0.01).The histological injury score in the control group was significantly higher than that in the terlipressin group on the 7th postoperative day(P<0.01).Conclusions:Splanc

关键词： Hepatectomy portal pressure terlipressin somatostatin

Endoscopic repair of delayed stomach perforation caused by penetrating trauma:A case report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2021年第5期9卷 1228-1236页

作者： jae Hyun yoon Chung Hwan Jun jae Pil Han Ji-Woong Yeom Seung-Ku Kang Hyun Yi Kook sung KyuChoi Department of Gastroenterology and Hepatology Chonnam National University Hospital and College of MedicineGwangju 61469South Korea Department of Internal Medicine Mokpo Hankook HospitalMokpo 58643South Korea Department of Surgery Mokpo Hankook HospitalMokpo 58643South Korea Department of Cardiothoracic Surgery Mokpo Hankook HospitalMokpo 58643South Korea Department of Nursing Chonnam National University Hospitaland College of NursingGwangju 61469South Korea

BACKGROUND Primary endoscopic closure of a perforated gastric wall during endoscopic procedures is mostly effective and well-tolerated;however,there are very few studies on the efficacy of endoscopic management of delayed traumatic gastric ***,we report a novel case of a patient who was successfully treated for delayed traumatic stomach perforation using an alternative endoscopic *** SUMMARY A 39-year-old woman presented with multiple penetrating traumas in the back and left abdominal *** imaging studies revealed left diaphragmatic disruption and peri-splenic hemorrhage without gastric *** emergency primary repair of the disrupted diaphragm with omental reduction and suturing of the lacerated lung was performed;however,delayed free perforation of the gastric wall was noted on computed tomography after 3 *** an emergency abdominal surgery for the primary repair of the gastric wall,re-perforation was noted 15 d *** high risk associated with re-surgery prompted an endoscopic intervention using 2 endoloops and 11 endoscopic clips using a novel modified purse-string suture *** free perforated gastric wall was successfully repaired without additional surgery or *** patient was discharged after 46 d without any *** Endoscopic closure with endoloops and clips can be a useful therapeutic alternative to re-surgery for delayed traumatic gastric perforation.

关键词： Surgical endoscopy Trauma Stomach Re-perforation Endoloop Case report

Features of extrahepatic metastasis after radiofrequency ablation for hepatocellular carcinoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2020年第32期26卷 4833-4845页

作者： jae H yoon Young J Goo Chae-Jun Lim sung K Choi sung B Cho Sang S Shin Chung H Jun Department of Gastroenterology Chonnam National University Hospital and Medical SchoolGwangju 61469South Korea Department of Gastroenterology Hwasun Chonnam National University Hospital and Medical SchoolHwasun 58128South Korea Department of Radiology Chonnam National University Hospital and Medical SchoolGwangju 61469South Korea Department of Internal Medicine Mokpo Hankook HospitalMokpo 58643South Korea

BACKGROUND Extrahepatic metastasis(EHM)of hepatocellular carcinoma(HCC)is associated with poor ***,the clinical features and risk factors of EHM of HCC after radiofrequency ablation(RFA)remain *** To elucidate the characteristics and risk factors of EHM after RFA for *** From January 2008 to December 2017,we retrospectively enrolled 661 patients who underwent RFA as first-line treatment for HCC at 2 tertiary *** inclusion criteria were age≥18 years,a diagnosis of HCC,and *** computed tomography(CT)or magnetic resonance imaging(MRI)and alpha-fetoprotein measurements were routinely performed at 1 mo after RFA and followed-up at intervals of 3-6 *** analyses were performed using the chi-squared test or Student’s t-test,and univariate and multivariate analyses were performed via logistic regression,as *** EHM was diagnosed in 44 patients(6.7%)during a median follow-up period of 1204 *** 10-year cumulative rate of HCC recurrence and EHM was 92.7%and 33.7%,*** recurrence was most often intrahepatic,and the rate of extrahepatic recurrence at initial recurrence was only 1.2%.The median time to the diagnosis of EHM was 2.68 years,and 68.2%of patients developed EHM within 2 years of the first recurrence,regardless of recurrence-free survival and 75.0%of patients developed EHM within 5 years after first *** was mostly diagnosed via abdominal CT/MRI in 33(75.0%)and 38 of 44 patients(86.4%)with EHM had either positive abdominal CT scan results or serum AFP level *** multivariate analysis,recurrence-free survival400 IU/mL were associated with a high EHM *** EHM occurs following multiple intrahepatic recurrences after RFA and combined contrast-enhanced abdominal CT and serum AFP were useful for *** especially with high-risk factors require close follow-up for

关键词： Hepatocellular carcinoma Metastasis Radiofrequency ablation Surveillance Risk factor

Grade-4 commercially pure titanium with ultrahigh strength achieved by twinning-induced grain refinement through cryogenic deformation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第7期66卷 193-201页

作者： Seong-Woo Choi jae Sukjeong Jong Woo Won jae Keun Hong yoon Suk Choi Titanium Department.Korea Institute of Materials Science Changwon51508Republic of Korea School of Materials Science and Engineering Pusan National UniversityPusan.46241Republic of Korea Materials and Manufacturing Development Team Doosan Heavy Industries and ConstructionChangwon51711Republic of Korea

The yield strength of commercially pure(CP) Ti of ASTM grade 4, the strongest among all the CP-Ti grades, is too low for structural applications that require high-strength materials. Here, we demonstrate the strengthening of grade-4 CP Ti by cryogenic-temperature rolling(CTR), which enables deformation twinning in grade-4 CP Ti to achieve twinning-induced grain refinement. CTR activated {11.22} twinning and {10.12} twinning, which are the most common twinning systems in pure Ti, whereas room-temperature rolling(RTR) did not activate any twinning system. CTR with imposing an area reduction of just 30% significantly increased the yield strength of the CP Ti to 946 MPa, which is not achievable through typical processes performed at or above room temperature and is comparable to that of commercial Ti-6 Al-4 V. The significant increase in strength was due to microstructural strengthening caused by twinning-induced grain refinement, combined with dislocation accumulation. In contrast to RTR, CTR greatly increased the stress concentration at grain boundaries(GBs), which caused the unusual activation of twinning in the grade-4 CP Ti by facilitating twin nucleation at GBs. The stress concentration increased because CTR activated the slip to a lesser extent compared to RTR, thereby reducing the strain compatibility between neighboring grains. These results will contribute to development of ultrahigh-strength CP Ti and may thereby extend its use to structural applications that require high-strength materials.

关键词： Titanium Twinning Cryogenic deformation Grain refinement Tensile properties