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Novel technique for measurement of coating layer thickness of fine and porous particles using focused ion beam

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Particuology 2019年第1期17卷 190-198页

作者： M. Goslinska I. Selmer C. Kleemann U.Kulozik I. Smirnova S. Heinrich Hamburg University of Technology Institute of Solids Process Engineering and Particle TechnologyDenickestr1521073 HamburgGermany Hamburg University of Technology Institute of Thermal Separation ProcessesEiJ^endorfer Str. 3821073 HamburgGermany Technical University of Munich Chair of Food and Bioprocess EngineeringWeihenstephaner Berg 185354 FreisingGermany

A novel technique for the measurement of the coating layer thickness of fine particles was developed in this work based on cross-sectioning of micrometre-sized single coated particles using focused ion beam (FIB) milling. This technique was tested on two batches of aerogel particles coated with thin coatings in a spouted bed. The FIB milling procedure consisted of two steps. First, the desired part of the coated particle was removed using a high ion beam current. The resulting cross-sectioned area was then polished using a lower ion beam current to make the cross-section clearly visible. The FIB milling process was controlled with simultaneous scanning electron microscopy (SEM). Afterwards, the coating layer thickness was evaluated using the SEM images. The coating layer was successfully applied on the porous aerogel microparticles in the spouted bed. The coating uniformity of the highly porous particles increased with increasing sprayed coating solution amount, with up to 91% of the particle pores being covered. The FIB-cross-sectioning technique using an ion beam of 2.50 nA for the first milling and 0.43 nA for polishing of the surface resulted in successful generation of cross-sections of representative particles with a visible particle core and coating layer. A coating layer thickness of approximately 700 nm was achieved on particles with sizes of below 45 μm.

关键词： Coating layer thickness focused ion beam Microparticle Aerogel Spouted bed Dilute spouting

Nonlinear Simulation of focused Wave Group Action on a Truncated Surface-Piercing Structure

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Journal of Marine Science and Application 2018年第3期17卷 362-370页

作者： Dezhi Ning Xiang Li Chongwei Zhang State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

In this study, we numerically investigated the nonlinear focused wave group action on a truncated surface-piercing structure, and developed a two-dimensional fully nonlinear numerical tank using the higher-order boundary element method. We determined the amplitude of the wave components of the focused wave group based on the JONSWAP wave spectrum. We discuss the effects of the presence of a surface-piercing structure on the characteristics of the focused wave group and find that the location of the structure does not evidently change the focal location or focal time of the focused wave group. The largest amplitudes of the run-up and horizontal force on the structure occur when the front surface of the structure is at the focal location. The critical draught and breadth of the structure occur when the wave run-up reaches its maximum along the structure.

关键词： focused wave Fully nonlinear Numerical wavetank Floating body Boundary element method

Decoding and calibration method on focused plenoptic camera

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Computational Visual Media 2016年第1期2卷 57-69页

作者： Chunping Zhang Zhe Ji Qing Wang School of Computer Science Northwestern Polytechnical University

The ability of light gathering of plenoptic camera opens up new opportunities for a wide range of computer vision applications. An efficient and accurate method to calibrate plenoptic camera is crucial for its development. This paper describes a 10-intrinsic-parameter model for focused plenoptic camera with misalignment. By exploiting the relationship between the raw image features and the depth–scale information in the scene, we propose to estimate the intrinsic parameters from raw images directly,with a parallel biplanar board which provides depth prior. The proposed method enables an accurate decoding of light field on both angular and positional information, and guarantees a unique solution for the 10 intrinsic parameters in geometry. Experiments on both simulation and real scene data validate the performance of the proposed calibration method.

关键词： calibration focused plenoptic camera depth prior intrinsic parameters

High intensity focused ultrasound in clinical tumor ablation

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World Journal of Clinical Oncology 2011年第1期2卷 8-27页

作者： Yu-Feng Zhou Division of Engineering Mechanics School of Mechanical and Aerospace EngineeringNanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

Recent advances in high intensity focused ultrasound(HIFU),which was developed in the 1940s as a viable thermal tissue ablation approach,have increased its popularity.In clinics,HIFU has been applied to treat a variety of solid malignant tumors in a well-defined volume,including the pancreas,liver,prostate,breast,uterine fibroids,and soft-tissue sarcomas.In comparison to conventional tumor/cancer treatment modalities,such as open surgery,radio-and chemo-therapy,HIFU has the advantages of non-invasion,non-ionization,and fewer complications after treatment.Over 100 000 cases have been treated throughout the world with great success.The fundamental principles of HIFU ablation are coagulative thermal necrosis due to the absorption of ultrasound energy during transmission in tissue and the induced cavitation damage.This paper reviews the clinical outcomes of HIFU ablation for applicable cancers,and then summarizes the recommendations for a satisfactory HIFU treatment according to clinical experience.In addition,the current challenges in HIFU for engineers and physicians are also included.More recent horizons have broadened the application of HIFU in tumor treatment,such as HIFU-mediated drug delivery,vessel occlusion,and soft tissue erosion(“histotripsy”).In summary,HIFU is likely to play a significant role in the future oncology practice.

关键词： High intensity focused ultrasound Thermal ablation Image-guided therapy Cancer Bubble cavitation Bioeffects

Retrospective analysis of eFAST ultrasounds performed on trauma activations at an academic level-1 trauma center

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World Journal of Emergency Medicine 2020年第1期11卷 12-17页

作者： Samantha Shwe Lauren Witchey Shadi Lahham Ethan Kunstadt Inna Shniter John C.Fox School of Medicine University of CaliforniaIrvine 92697USA Department of Emergency Medicine University of CaliforniaIrvineOrangeCA 92868USA

BACKGROUND:Point-of-care ultrasound(POCUS)has become increasingly integrated into the practice of emergency medicine.A common application is the extended focused assessment with sonography in trauma(eFAST)exam.The American College of Emergency Physicians has guidelines regarding the scope of ultrasound in the emergency department and the appropriate documentation.The objective of this study was to conduct a review of performed,documented and billed eFAST ultrasounds on trauma activation patients.METHODS:This was a retrospective review of all trauma activation patients during a 10-month period at an academic level-one trauma center.A list comparing all trauma activations was crossreferenced with a list of all billed eFAST scans.Medical records were reviewed to determine whether an eFAST was indicated,performed,and appropriately documented.RESULTS:We found that 1,507 of 1,597 trauma patients had indications for eFAST,but 396(27%)of these patients did not have a billed eFAST.Of these 396 patients,87(22%)had documentation in the provider note that an eFAST was performed but there was no separate procedure note.The remaining 309(78%)did not have any documentation of the eFAST in the patient’s chart although an eFAST was recorded and reviewed during ultrasound quality assurance.CONCLUSION:A significant proportion of trauma patients had eFAST exams performed but were not documented or billed.Lack of documentation was multifactorial.Emergency ultrasound programs require appropriate reimbursement to support training,credentialing,equipment,quality assurance,and device maintenance.Our study demonstrates a significant absence of adequate documentation leading to potential revenue loss for an emergency ultrasound program.

关键词： Point-of-care ultrasound Emergency medicine focused assessment withsonography in trauma Trauma activation Blunt trauma

Techniques and physical properties of 10MHz short pulse focused ultrasonic transducer

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声学技术 2004年第S1期23卷 15-17,22页

作者： ZHU Guozhen, YANG Yong, LU Kean (Department of Physics, Tsinghua University, Beijing 100084, China) Department of Physics Tsinghua University Beijing 100084 China

A focused ultrasonic transducer used for biomedical purposes with a fundamental frequency of 10MHz and a pulse width of one and a half periods is described in this paper. Its physical properties are given including (1) focused acoustic field recorded by an optical means, (2) electric waveform for triggering the transducer and the corresponding waveform of the wave received by another transducer, and (3) result of tests on a sample object.

关键词： focused transducer short pulse ultrasonic medicine nondestructive testing

Systematic review of ablative therapy for the treatment of renal allograft neoplasms

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World Journal of Clinical Cases 2019年第17期7卷 2487-2504页

作者： Evaldo Favi Nicholas Raison Federico Ambrogi Serena Delbue Maria Chiara Clementi Luca Lamperti Marta Perego Matteo Bischeri Mariano Ferraresso Renal Transplantation Fondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoMilan 20122Italy MRC Centre for Transplantation King’s College LondonLondon WC2R 2LSUnited Kingdom Department of Clinical Sciences and Community Health University of MilanMilan 20122Italy Department of Biomedical Surgical and Dental SciencesUniversity of MilanMilan 20100Italy

BACKGROUND To date,there are no guidelines on the treatment of solid neoplasms in the transplanted kidney.Historically,allograft nephrectomy has been considered the only reasonable option.More recently,nephron-sparing surgery (NSS) and ablative therapy (AT) have been proposed as alternative procedures in selected cases.AIM To review outcomes of AT for the treatment of renal allograft tumours.METHODS We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 Checklist.PubMed was searched in March 2019 without time restrictions for all papers reporting on radiofrequency ablation (RFA),cryoablation (CA),microwave ablation (MWA),high-intensity focused ultrasound (HIFU),and irreversible electroporation (IRE) of solid tumours of the kidney allograft.Only original manuscripts describing actual cases and edited in English were considered.All relevant articles were accessed in full text.Additional searches included all pertinent references.Selected studies were also assessed for methodological quality using a tool based on a modification of the Newcastle Ottawa scale.Data on recipient characteristics,transplant characteristics,disease characteristics,treatment protocols,and treatment outcomes were extracted and analysed.Given the nature and the quality of the studies available (mostly retrospective case reports and small retrospective uncontrolled case series),a descriptive summary was provided.RESULTS Twenty-eight relevant studies were selected describing a total of 100 AT procedures in 92 patients.Recipient age at diagnosis ranged from 21 to 71 years whereas time from transplant to diagnosis ranged from 0.1 to 312 mo.Most of the neoplasms were asymptomatic and diagnosed incidentally during imaging carried out for screening purposes or for other clinical reasons.Preferred diagnostic modality was Doppler-ultrasound scan followed by computed tomography scan,and magnetic resonance imaging.Main tumour types were: papillary renal cell carcinoma (RCC) and clear cel

关键词： Ablative therapy Cryoablation Radiofrequency ablation Microwave ablation High-intensity focused ultrasonography Irreversible electroporation Neoplasm Kidney transplant Renal allograft Systematic review

Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment

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World Journal of Radiology 2016年第3期8卷 298-307页

作者： Maythem Saeed Roland Krug Loi Do Steven W Hetts Mark W Wilson Department of Radiology and Biomedical Imaging School of Medicine University of California San Francisco

AIM: To use magnetic resonance-guided high intensity focused ultrasound(MRg-HIFU), magnetic resonance imaging(MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue. METHODS: Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication(n = 24) using a 3T-MRg-HIFU(1.1 MHz frequency and 3000J-4400 J energies). T2-weighted fast spin echo(T2-W), perfusion saturation recovery gradient echo and contrast enhanced(CE) T1-weighted(T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically significant.RESULTS: Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or nonCE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images invivo(0.12-0.36 cm3 for single sonication 3000 J, 0.50-0.84 cm3, for double 3000 J, 0.75-0.78 cm3 for single 4400 J and 0.12-2.65 cm3 for double 4400J) and at postmortem(0.23-0.52 cm3, 0.25-0.82 cm3, 0.45-0.68 cm3 and 0.29-1.80 cm3, respectively) were comparable. The ablated volumes on 3000 J and 4400 J double sonication were significantly larger than single(P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively.CONCLUSION: Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.

关键词： Magnetic resonance-guided high intensity focused ultrasound Renal ablation Magnetic resonance imaging Microscopy High intensity focused ultrasound

High-intensity focused ultrasound ablation:An effective bridging therapy for hepatocellular carcinoma patients

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World Journal of Gastroenterology 2013年第20期19卷 3083-3089页

作者： Tan To Cheung Sheung Tat Fan See Ching Chan Kenneth SH Chok Ferdinand SK Chu Caroline R Jenkins Regina CL Lo James YY Fung Albert CY Chan William W Sharr Simon HY Tsang Wing Chiu Dai Ronnie TP Poon Chung Mau Lo Department of Surgery the University of Hong Kong State Key Laboratory for Liver Research the University of Hong Kong Department of Diagnostic Radiology the University of Hong Kong Department of Anaesthesiology The University of Hong Kong Department of Pathology the University of Hong Kong Department of Medicine the University of Hong Kong

AIM:To analyze whether high-intensity focused ultrasound(HIFU) ablation is an effective bridging therapy for patients with hepatocellular carcinoma(HCC).METHODS:From January 2007 to December 2010,49 consecutive HCC patients were listed for liver transplantation(UCSF criteria).The median waiting time for transplantation was 9.5 mo.Twenty-nine patients received transarterial chemoembolization(TACE) as a bringing therapy and 16 patients received no treatment before transplantation.Five patients received HIFU ablation as a bridging therapy.Another five patients with the same tumor staging(within the UCSF criteria) who received HIFU ablation but not on the transplant list were included for comparison.Patients were comparable in terms of Child-Pugh and model for end-stage liver disease scores,tumor size and number,and cause of cirrhosis.RESULTS:The HIFU group and TACE group showed no difference in terms of tumor size and tumor number.One patient in the HIFU group and no patient in the TACE group had gross ascites.The median hospital stay was 1 d(range,1-21 d) in the TACE group and two days(range,1-9 d) in the HIFU group(P < 0.000).No HIFU-related complication occurred.In the HIFU group,nine patients(90%) had complete response and one patient(10%) had partial response to the treatment.In the TACE group,only one patient(3%) had response to the treatment while 14 patients(48%) had stable disease and 14 patients(48%) had progressive disease(P = 0.00).Seven patients in the TACE group and no patient in the HIFU group dropped out from the transplant waiting list(P = 0.559).CONCLUSION:HIFU ablation is safe and effective in the treatment of HCC for patients with advanced cirrhosis.It may reduce the drop-out rate of liver transplant candidate.

关键词： Ablation Bridging therapy Cirrhosis Hepatocellular carcinoma High-intensity focused ultrasound Liver transplant New technology