AIM:To describe our own experience with pyogenic liver abscesses over the past 10 years and investigate the risk factors associated with failure of initial percutaneous therapy.METHODS:A retrospective study of records...AIM:To describe our own experience with pyogenic liver abscesses over the past 10 years and investigate the risk factors associated with failure of initial percutaneous therapy.METHODS:A retrospective study of records of 63 PLA patients presenting between 1998 and 2008 to Australian tertiary referral centre,were reviewed.Amoebic and hydatid abscesses were excluded.Demographic,clinical,radiological,and microbiological characteristics,as well as surgical/radiological interventions,were recorded.RESULTS:Sixty-three patients(42 males,21 females) aged 65(±14) years[mean±(SD) ]had prodromal symptoms for a median(interquartile range;IQR) of 7(5-14) d.Only 59%of patients were febrile at presentation;however,the serum C-reactive protein was elevated in all 47 in whom it was measured.Liver function tests were non-specifically abnormal.67%of patients had a solitary abscess,while 32%had>3 abscesses with a median(IQR) diameter of 6.3(4-9) cm.Causative organisms were:Streptococcus milleri 25%,Klebsiella pneumoniae 21%,and Escherichia coli 16%.A presumptive cryptogenic cause was most common (34%).Four patients died in this series:one from sepsis,two from advanced cancer,and one from acute myocardial infarction.The initial procedure was radiological aspiration±drainage in 54 and surgery in two patients.17%underwent surgical management during their hospitalization.Serum hypoalbuminaemia[mean (95%CI) :32(29-35) g/L vs 28(25-31) g/L,P=0.045] on presentation was found to be the only factor related to failure of initial percutaneous therapy on univariate analysis.CONCLUSION:PLA is a diagnostic challenge,because the presentation of this condition is non-specific.Intravenous antibiotics and radiological drainage in the first instance allows resolution of most PLAs;However,a small proportion of patients still require surgical drainage.展开更多
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. ...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.展开更多
To evaluate the clinical efficacy of concentrated growth factors(CGFs)combined with mineralized collagen(MC)in guided bone regeneration(GBR).A retrospective study involving 29 patients treated with GBR technique,which...To evaluate the clinical efficacy of concentrated growth factors(CGFs)combined with mineralized collagen(MC)in guided bone regeneration(GBR).A retrospective study involving 29 patients treated with GBR technique,which was performed either CGF and MC complexes or MC alone.Implants were inserted simultaneously and cone-beam computed tomography was taken immediately,at 3 and 6 months postoperation.Questionnaires were completed by all patients so as to evaluate the main symptoms and daily activities during the first week after surgery.The outcomes of the two groups were statistically compared.All implants healed uneventfully.Patients in both groups suffered from different levels of discomfort for the reason of swelling,pain and chewing impairment on 1-2 days.Meanwhile,swelling of the Trial group was weaker than the Control group.When compared with the Control group,pain levels in Trial group were more rapidly reduced and patients took fewer analgesics from Day 3.Furthermore,the reconstitution mean value of the graft was thicker at 3 and 6 months in Trial group.CGFs complex with MC were beneficial to relieve the clinical symptoms,promote the peri-implant bone regeneration and shorten the healing time.展开更多
A novel calcium-phosphate(Ca–P)-coated magnesium(Mg) membrane used for guided bone regeneration(GBR) was studied.The microstructural characterization, electrochemical test, immersion test,fluorescence labeling analys...A novel calcium-phosphate(Ca–P)-coated magnesium(Mg) membrane used for guided bone regeneration(GBR) was studied.The microstructural characterization, electrochemical test, immersion test,fluorescence labeling analysis and histopathological evaluation were carried out.The results showed that Ca–P coating could obviously improve the corrosion resistance of the pure Mg membrane.The in vivo results showed that Mg membrane coated with Ca–P would take 8 weeks to be completely absorbed.However, Mg membrane was completely absorbed within 1 week.Histopathological evaluation showed that the Ca–P-coated Mg membranes were significantly better than Ti membranes at the early implantation time(4 weeks), and with the time prolonging,the performance of the coated Mg membrane was not as good as pure Ti membranes(but still better than blank group) at 8 and 12 weeks.The coated biodegradable Mg membrane had a good promising application in GBR.But further studies have to be done to further decrease the degradation rate of pure Mg membrane.展开更多
The factors influencing the incidence of common complications（pneumothorax and pulmonary hemorrhage） of CT-guided percutaneous needle biopsy of lumps near pulmonary hilum were investigated. CT-guided percutaneous ne...The factors influencing the incidence of common complications（pneumothorax and pulmonary hemorrhage） of CT-guided percutaneous needle biopsy of lumps near pulmonary hilum were investigated. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum was performed on 48 patients. The complications of pneumothorax and pneumorrhagia as well as the contributing factors were analyzed statistically. The major complications associated with CT-guided needle biopsy included pneumothorax（13 cases, 27.1%） and pulmonary hemorrhage（14 cases, 20.24%）. ？2 test revealed that pneumothorax was associated with the lesion size and depth of needle penetration, and pulmonary hemorrhage with the depth of needle penetration and needle retention time with a significant P value. Pneumothorax was observed in 7 cases（17.5%） out of 40 cases with diameter of mass greater than 3 cm, and in 6 cases（60%） out of 10 cases with depth of needle penetration greater than 4 cm. Additionally, pulmonary hemorrhage was identified in 12 cases（41.4%） out of 29 cases with needle retention time longer than 15 min, and pulmonary hemorrhage in 7 cases（70%） out of 10 cases with depth of needle penetration greater than 4 cm. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum is safe and effective. The key factors to prevent the complications include correct evaluation of lesion size, depth of needle penetration and the needle retention time before the operation. Key words： biopsy, CT-guided; hilum; pneumothorax; pulmonary hemorrhage展开更多
The oral and maxillofacial regions have complex anatomical structures and different tissue types,which have vital health and aesthetic functions.Biodegradable metals(BMs)is a promising bioactive materials to treat ora...The oral and maxillofacial regions have complex anatomical structures and different tissue types,which have vital health and aesthetic functions.Biodegradable metals(BMs)is a promising bioactive materials to treat oral and maxillofacial diseases.This review summarizes the research status and future research directions of BMs for oral and maxillofacial applications.Mg-based BMs and Zn-based BMs for bone fracture fixation systems,and guided bone regeneration(GBR)membranes,are discussed in detail.Zn-based BMs with a moderate degradation rate and superior mechanical properties for GBR membranes show great potential for clinical translation.Fe-based BMs have a relatively low degradation rate and insoluble degradation products,which greatly limit their application and clinical translation.Furthermore,we proposed potential future research directions for BMs in the oral and maxillofacial regions,including 3D printed BM bone scaffolds,surface modification for BMs GBR membranes,and BMs containing hydrogels for cartilage regeneration,soft tissue regeneration,and nerve regeneration.Taken together,the progress made in the development of BMs in oral and maxillofacial regions has laid a foundation for further clinical translation.展开更多
Based on guided wave theory and considering the grouted rock bolt as waveguide medium, we have constructed a three dimensional model of grouted rock bolt with the dynamics of finite difference numerical simulation sof...Based on guided wave theory and considering the grouted rock bolt as waveguide medium, we have constructed a three dimensional model of grouted rock bolt with the dynamics of finite difference numerical simulation software FLAC3D4.0, and simulated the propagation behavior of the guided wave in the full grouted rock bolt. The simulated waveform and wave velocity matched well with the experimental results. We have made a more in-depth and comprehensive study of the wave velocity, wave component and attenuation characteristics of the guided wave propagating in rock bolt, and found some new characteristics and phenomena. In addition, some phenomena that haven’t been explained in the previous researches have also been discussed in this paper. The result showed that when guided wave propagates in grouted rock bolt, after the body wave decays, there is still the interface wave-Stoneley wave that does not decay in the axial direction of the bolt. The findings can provide some reference for rock bolt testing and the selection of the optimal excitation wave of testing.展开更多
Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (J...Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (JSSRE) method was proposed to separate multiple modes in long bones. First, the Gabor time-frequency transform was applied to obtain the spectrogram of multimodal signals. Then, a multi-class image segmentation algorithm was used to find the corresponding region of each mode in the spectrogram, including an improved watershed transform and a region growing procedure. Finally, the ridges were extracted and the time domain signals representing individual modes were reconstructed from these ridges in each region. The validations of this method were discussed by simulated multimodal signals with different signal-to-noise ratios (SNR). The correlation coefficients between the original signals without noise and the reconstructed signals were calculated to analyze the results quantitatively. The results showed that the extracted ridges were in good agreement with generated theoretical dispersion curves, and the reconstructed signals were highly related to the original signals, even under the SNR=3 dB situation.展开更多
Appropriately adapted comprehensive mechanical properties,degradation behavior and biocompatibility are prerequisites for the application of Zn-based biodegradable implants.In this study,hot-extruded Zn-0.5Cu-xFe(x=0....Appropriately adapted comprehensive mechanical properties,degradation behavior and biocompatibility are prerequisites for the application of Zn-based biodegradable implants.In this study,hot-extruded Zn-0.5Cu-xFe(x=0.1,0.2 and 0.4 wt%)alloys were fabricated as candidates for biodegradable materials for guided bone regeneration(GBR)membranes.The hot-extrusion process and Cu alloying were expected mostly to enhance the mechanical properties,and the Fe alloying was added mainly for regulating the degradation.The microstructure,mechanical properties and in vitro degradation behavior were systematically investigated.The ZnCuFe alloys were composed of a Zn matrix and FeZn13 phase.With increasing Fe content,a higher FeZn13 phase precipitation with larger particles was observed.Since elongation declined significantly until fracture with increasing Fe content up to 0.4 wt%,the ZnCuFe(0.2 wt%)alloy achieved a good balance between mechanical strength and ductility,with an ultimate tensile strength of 202.3 MPa and elongation at fracture of 41.2%.Moreover,the addition of Fe successfully accelerated the degradation of ZnCuFe alloys.The ZnCuFe(0.2 wt%)alloy showed relatively uniform corrosion in the long-term degradation test.Furthermore,extracts of the ZnCuFe(0.2 wt%)alloy showed no apparent cytotoxic effects against L929 fibroblasts,Saos-2 osteoblasts or TAg periosteal cells.The ZnCuFe(0.2 wt%)alloy exhibited the potential to inhibit bacterial adhesion of Streptococcus gordonii and mixed oral bacteria.Our study provides evidence that the ZnCuFe(0.2 wt%)alloy can represent a promising material for the application as a suitable GBR membrane.展开更多
The linear echoendoscope,introduced in the 1990s,opened the era of interventional endoscopic ultrasound(IEUS).The linear echoendoscope enabled EUS guided Fine Needle Aspiration(EUS-FNA) allowing the path of the needle...The linear echoendoscope,introduced in the 1990s,opened the era of interventional endoscopic ultrasound(IEUS).The linear echoendoscope enabled EUS guided Fine Needle Aspiration(EUS-FNA) allowing the path of the needle to be traced during the puncture process.After EUS-FNA,other interventional procedures were introduced in clinical practice.Tissue acquisition was the first EUS-guided interventional procedure and its higher diagnostic quality has undoubtedly been established.After EUS-FNA,Celiac plexus neurolysis(CPN) and block(CPB),pancreatic pseudocyst drainage,abdominal and mediastinal collections/abscesses drainage,and in selected cases,pancreatic and biliary ductal system drainage,were introduced in clinical practice.EUS-guided fine needle injection with local delivery of antitumor agents is considered a promising modality.We have reviewed published data on EUS guided interventional procedures with the object of summarizing the diagnostic capability of endoscopic ultrasound and elaborates in detail its therapeutic capability and potential.展开更多
Automated Guided Vehicles(AGVs)have been introduced into various applications,such as automated warehouse systems,flexible manufacturing systems,and container terminal systems.However,few publications have outlined pr...Automated Guided Vehicles(AGVs)have been introduced into various applications,such as automated warehouse systems,flexible manufacturing systems,and container terminal systems.However,few publications have outlined problems in need of attention in AGV applications comprehensively.In this paper,several key issues and essential models are presented.First,the advantages and disadvantages of centralized and decentralized AGVs systems were compared;second,warehouse layout and operation optimization were introduced,including some omitted areas,such as AGVs fleet size and electrical energy management;third,AGVs scheduling algorithms in chessboardlike environments were analyzed;fourth,the classical route-planning algorithms for single AGV and multiple AGVs were presented,and some Artificial Intelligence(AI)-based decision-making algorithms were reviewed.Furthermore,a novel idea for accelerating route planning by combining Reinforcement Learning(RL)andDijkstra’s algorithm was presented,and a novel idea of the multi-AGV route-planning method of combining dynamic programming and Monte-Carlo tree search was proposed to reduce the energy cost of systems.展开更多
文摘AIM:To describe our own experience with pyogenic liver abscesses over the past 10 years and investigate the risk factors associated with failure of initial percutaneous therapy.METHODS:A retrospective study of records of 63 PLA patients presenting between 1998 and 2008 to Australian tertiary referral centre,were reviewed.Amoebic and hydatid abscesses were excluded.Demographic,clinical,radiological,and microbiological characteristics,as well as surgical/radiological interventions,were recorded.RESULTS:Sixty-three patients(42 males,21 females) aged 65(±14) years[mean±(SD) ]had prodromal symptoms for a median(interquartile range;IQR) of 7(5-14) d.Only 59%of patients were febrile at presentation;however,the serum C-reactive protein was elevated in all 47 in whom it was measured.Liver function tests were non-specifically abnormal.67%of patients had a solitary abscess,while 32%had>3 abscesses with a median(IQR) diameter of 6.3(4-9) cm.Causative organisms were:Streptococcus milleri 25%,Klebsiella pneumoniae 21%,and Escherichia coli 16%.A presumptive cryptogenic cause was most common (34%).Four patients died in this series:one from sepsis,two from advanced cancer,and one from acute myocardial infarction.The initial procedure was radiological aspiration±drainage in 54 and surgery in two patients.17%underwent surgical management during their hospitalization.Serum hypoalbuminaemia[mean (95%CI) :32(29-35) g/L vs 28(25-31) g/L,P=0.045] on presentation was found to be the only factor related to failure of initial percutaneous therapy on univariate analysis.CONCLUSION:PLA is a diagnostic challenge,because the presentation of this condition is non-specific.Intravenous antibiotics and radiological drainage in the first instance allows resolution of most PLAs;However,a small proportion of patients still require surgical drainage.
文摘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.
基金funded by China Postdoctoral Science Foundation Grant(No.2019M652380).
文摘To evaluate the clinical efficacy of concentrated growth factors(CGFs)combined with mineralized collagen(MC)in guided bone regeneration(GBR).A retrospective study involving 29 patients treated with GBR technique,which was performed either CGF and MC complexes or MC alone.Implants were inserted simultaneously and cone-beam computed tomography was taken immediately,at 3 and 6 months postoperation.Questionnaires were completed by all patients so as to evaluate the main symptoms and daily activities during the first week after surgery.The outcomes of the two groups were statistically compared.All implants healed uneventfully.Patients in both groups suffered from different levels of discomfort for the reason of swelling,pain and chewing impairment on 1-2 days.Meanwhile,swelling of the Trial group was weaker than the Control group.When compared with the Control group,pain levels in Trial group were more rapidly reduced and patients took fewer analgesics from Day 3.Furthermore,the reconstitution mean value of the graft was thicker at 3 and 6 months in Trial group.CGFs complex with MC were beneficial to relieve the clinical symptoms,promote the peri-implant bone regeneration and shorten the healing time.
基金financially supported by the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement (Nos.2016YFC1101804 and 2016YFC1100604)Shenyang Key R&D and Technology Transfer Program (No.Z18-0-027)
文摘A novel calcium-phosphate(Ca–P)-coated magnesium(Mg) membrane used for guided bone regeneration(GBR) was studied.The microstructural characterization, electrochemical test, immersion test,fluorescence labeling analysis and histopathological evaluation were carried out.The results showed that Ca–P coating could obviously improve the corrosion resistance of the pure Mg membrane.The in vivo results showed that Mg membrane coated with Ca–P would take 8 weeks to be completely absorbed.However, Mg membrane was completely absorbed within 1 week.Histopathological evaluation showed that the Ca–P-coated Mg membranes were significantly better than Ti membranes at the early implantation time(4 weeks), and with the time prolonging,the performance of the coated Mg membrane was not as good as pure Ti membranes(but still better than blank group) at 8 and 12 weeks.The coated biodegradable Mg membrane had a good promising application in GBR.But further studies have to be done to further decrease the degradation rate of pure Mg membrane.
基金supported by the National Natural Science Foundation of China(No.81102074)
文摘The factors influencing the incidence of common complications（pneumothorax and pulmonary hemorrhage） of CT-guided percutaneous needle biopsy of lumps near pulmonary hilum were investigated. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum was performed on 48 patients. The complications of pneumothorax and pneumorrhagia as well as the contributing factors were analyzed statistically. The major complications associated with CT-guided needle biopsy included pneumothorax（13 cases, 27.1%） and pulmonary hemorrhage（14 cases, 20.24%）. ？2 test revealed that pneumothorax was associated with the lesion size and depth of needle penetration, and pulmonary hemorrhage with the depth of needle penetration and needle retention time with a significant P value. Pneumothorax was observed in 7 cases（17.5%） out of 40 cases with diameter of mass greater than 3 cm, and in 6 cases（60%） out of 10 cases with depth of needle penetration greater than 4 cm. Additionally, pulmonary hemorrhage was identified in 12 cases（41.4%） out of 29 cases with needle retention time longer than 15 min, and pulmonary hemorrhage in 7 cases（70%） out of 10 cases with depth of needle penetration greater than 4 cm. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum is safe and effective. The key factors to prevent the complications include correct evaluation of lesion size, depth of needle penetration and the needle retention time before the operation. Key words： biopsy, CT-guided; hilum; pneumothorax; pulmonary hemorrhage
基金the National Natural Science Foundation of China[grant numbers 51901003,51931001,51871004,and 81771039]the National Key R&D Program of China[grant number 2018YFE0104200]+1 种基金the Key Research and Development Program of Ningxia Hui Autonomous Region[grant number 2018BEG02012]the Open Project of NMPA Key laboratory for Dental Materials[grant number PKUSS20200401].
文摘The oral and maxillofacial regions have complex anatomical structures and different tissue types,which have vital health and aesthetic functions.Biodegradable metals(BMs)is a promising bioactive materials to treat oral and maxillofacial diseases.This review summarizes the research status and future research directions of BMs for oral and maxillofacial applications.Mg-based BMs and Zn-based BMs for bone fracture fixation systems,and guided bone regeneration(GBR)membranes,are discussed in detail.Zn-based BMs with a moderate degradation rate and superior mechanical properties for GBR membranes show great potential for clinical translation.Fe-based BMs have a relatively low degradation rate and insoluble degradation products,which greatly limit their application and clinical translation.Furthermore,we proposed potential future research directions for BMs in the oral and maxillofacial regions,including 3D printed BM bone scaffolds,surface modification for BMs GBR membranes,and BMs containing hydrogels for cartilage regeneration,soft tissue regeneration,and nerve regeneration.Taken together,the progress made in the development of BMs in oral and maxillofacial regions has laid a foundation for further clinical translation.
基金supported by the Specialized Research Fund for the Doc-toral Program of Higher Education (Grant No. 20090211110016)the Gansu Provincial Natural Science Foundation of China (Grant No. 096RJZA048)
文摘Based on guided wave theory and considering the grouted rock bolt as waveguide medium, we have constructed a three dimensional model of grouted rock bolt with the dynamics of finite difference numerical simulation software FLAC3D4.0, and simulated the propagation behavior of the guided wave in the full grouted rock bolt. The simulated waveform and wave velocity matched well with the experimental results. We have made a more in-depth and comprehensive study of the wave velocity, wave component and attenuation characteristics of the guided wave propagating in rock bolt, and found some new characteristics and phenomena. In addition, some phenomena that haven’t been explained in the previous researches have also been discussed in this paper. The result showed that when guided wave propagates in grouted rock bolt, after the body wave decays, there is still the interface wave-Stoneley wave that does not decay in the axial direction of the bolt. The findings can provide some reference for rock bolt testing and the selection of the optimal excitation wave of testing.
基金supported by the National Natural Science Foundation of China(Grant No. 11174060)the PhD Programs Foundation of the Ministry of Education of China(Grant Nos. 20090071110066 and 20110071130004)the New Century Excellent Talents of the Ministry of Education of China(Grant No. NCET-10-0349)
文摘Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (JSSRE) method was proposed to separate multiple modes in long bones. First, the Gabor time-frequency transform was applied to obtain the spectrogram of multimodal signals. Then, a multi-class image segmentation algorithm was used to find the corresponding region of each mode in the spectrogram, including an improved watershed transform and a region growing procedure. Finally, the ridges were extracted and the time domain signals representing individual modes were reconstructed from these ridges in each region. The validations of this method were discussed by simulated multimodal signals with different signal-to-noise ratios (SNR). The correlation coefficients between the original signals without noise and the reconstructed signals were calculated to analyze the results quantitatively. The results showed that the extracted ridges were in good agreement with generated theoretical dispersion curves, and the reconstructed signals were highly related to the original signals, even under the SNR=3 dB situation.
基金the program of project-related personal exchange of person promoting international mobility of researchers(PPP)jointly funded by the(DAAD)German Academic Exchange Service and(CSC)China Scholarship Council:DAAD grant OsteoZink(Project-ID 57390341)This research was funded by National Key Research and Development Plan(Grant No.2016YFC1102500)+1 种基金Sichuan Science and Technology Program Under(Grant No.2020YFH0077)We would like also to thank the Analytical and Testing Center of Southwest Jiaotong University for the characterization analysis and discussion.The authors would also like to acknowledge scientific advice from Dr.Lutz Scheideler and excellent technical assistance of Mr.Ernst Schweizer and Mrs.Evi Kimmerle-Müller from Section Medical Materials Science and Technology,University Hospital Tübingen.
文摘Appropriately adapted comprehensive mechanical properties,degradation behavior and biocompatibility are prerequisites for the application of Zn-based biodegradable implants.In this study,hot-extruded Zn-0.5Cu-xFe(x=0.1,0.2 and 0.4 wt%)alloys were fabricated as candidates for biodegradable materials for guided bone regeneration(GBR)membranes.The hot-extrusion process and Cu alloying were expected mostly to enhance the mechanical properties,and the Fe alloying was added mainly for regulating the degradation.The microstructure,mechanical properties and in vitro degradation behavior were systematically investigated.The ZnCuFe alloys were composed of a Zn matrix and FeZn13 phase.With increasing Fe content,a higher FeZn13 phase precipitation with larger particles was observed.Since elongation declined significantly until fracture with increasing Fe content up to 0.4 wt%,the ZnCuFe(0.2 wt%)alloy achieved a good balance between mechanical strength and ductility,with an ultimate tensile strength of 202.3 MPa and elongation at fracture of 41.2%.Moreover,the addition of Fe successfully accelerated the degradation of ZnCuFe alloys.The ZnCuFe(0.2 wt%)alloy showed relatively uniform corrosion in the long-term degradation test.Furthermore,extracts of the ZnCuFe(0.2 wt%)alloy showed no apparent cytotoxic effects against L929 fibroblasts,Saos-2 osteoblasts or TAg periosteal cells.The ZnCuFe(0.2 wt%)alloy exhibited the potential to inhibit bacterial adhesion of Streptococcus gordonii and mixed oral bacteria.Our study provides evidence that the ZnCuFe(0.2 wt%)alloy can represent a promising material for the application as a suitable GBR membrane.
文摘The linear echoendoscope,introduced in the 1990s,opened the era of interventional endoscopic ultrasound(IEUS).The linear echoendoscope enabled EUS guided Fine Needle Aspiration(EUS-FNA) allowing the path of the needle to be traced during the puncture process.After EUS-FNA,other interventional procedures were introduced in clinical practice.Tissue acquisition was the first EUS-guided interventional procedure and its higher diagnostic quality has undoubtedly been established.After EUS-FNA,Celiac plexus neurolysis(CPN) and block(CPB),pancreatic pseudocyst drainage,abdominal and mediastinal collections/abscesses drainage,and in selected cases,pancreatic and biliary ductal system drainage,were introduced in clinical practice.EUS-guided fine needle injection with local delivery of antitumor agents is considered a promising modality.We have reviewed published data on EUS guided interventional procedures with the object of summarizing the diagnostic capability of endoscopic ultrasound and elaborates in detail its therapeutic capability and potential.
文摘Automated Guided Vehicles(AGVs)have been introduced into various applications,such as automated warehouse systems,flexible manufacturing systems,and container terminal systems.However,few publications have outlined problems in need of attention in AGV applications comprehensively.In this paper,several key issues and essential models are presented.First,the advantages and disadvantages of centralized and decentralized AGVs systems were compared;second,warehouse layout and operation optimization were introduced,including some omitted areas,such as AGVs fleet size and electrical energy management;third,AGVs scheduling algorithms in chessboardlike environments were analyzed;fourth,the classical route-planning algorithms for single AGV and multiple AGVs were presented,and some Artificial Intelligence(AI)-based decision-making algorithms were reviewed.Furthermore,a novel idea for accelerating route planning by combining Reinforcement Learning(RL)andDijkstra’s algorithm was presented,and a novel idea of the multi-AGV route-planning method of combining dynamic programming and Monte-Carlo tree search was proposed to reduce the energy cost of systems.
