• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.473-478
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• 2016

Hepatocellular cancer is a very common cause of cancer related deaths worldwide. Only 30-40% of patients present with early-stage disease open to curative treatments, such as resection or transplantation, while others can only undergo local therapies or palliative care. Various trans-arterial approaches have been used for treatment of hepatocellular carcinoma in patients who need a down-staging to liver transplantation, and who are not candidates for transplantation or radiofrequency ablation. Transarterial chemoembolization (TACE), transarterial embolization (TAE), drug-eluting beads, and radioembolization have been used for locoregional control, and have been shown to prolong the overall survival when compared with supportive care. In this review, we discuss patient selection, pre- and post-procedure imaging, techniques, safety, and clinical outcomes related to these therapies. Newer advances with future directions in various fields related to trans-arterial therapies are also discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.359-370
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• 1994

The reconstruction of major head and neck defects must be an integral part of the overall cancer treatment plan. The priorities of surgical treatment of head and neck tumor are 1) local tumor control, 2) relief of pain, 3) avoidance of difficult dressing, 4) provision of oral continence, and 5) ability to swallow and manage saliva. The recent advances in reconstructive surgery including the development of musculocutaneous flaps and microvascular free tissue transfer have allowed the surgical restoration of head and neck tumor defects that previously were not possible. These techniques have provided the opportunity to undertake larger, more aggressive resection while at the same time permitting functional rehabilitation. The timing of reconstruction demands on the nature of the resection, the ability of the ablative and reconstructive teams to coordinate efforts, the overall health of the patients, the patient's needs and wishes. So, we report to emphasize current methods for restoring major head and neck tumor defects after tumor ablation, reviewing for the reconstructive operations, postoperative complications, and postoperative sequelae etc, of patients from Jan, 1990 to Dec, 1993.

• BMB Reports
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• v.53 no.7
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• pp.349-356
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• 2020

Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.364-364
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• 2009

The solar cell is in the spotlight as a future green energy source. In the solar cells based on silicon wafer, the improvement of efficiency is one of crucial issues. One of techniques for high efficiency is texturing on the surface of solar cells. We studied the laser texturing on the surface of multi-crystalline silicon solar cells. The laser texturing followed by chemical etching is adequate for the multi-crystalline structure which have random crystallographic directions. We used the fiber laser for texturing and the SiNx as a masking layer for etching process. We investigated the shapes of holes for texturing in the various laser power conditions and analyzed the holes after removal of thermal damages caused by laser ablation through a 3D profiler.

• Journal of Powder Materials
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• v.9 no.4
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• pp.267-272
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• 2002

The production of micro components is one of the leading technologies in the fields of information and communiation, medical and biotechnology, and micro sensor and micro actuator system. Microfabrication (micromachining) techniques such as X-ray lithography, electroforming, micromolding and excimer laser ablation are used for the production of micro components out of silicon, polymer and a limited number of pure metals or binary alloys. However, since the first development of microfabrication technologies there have been demands for the cost-effective replication in large scale series as well as the extended range of available material. One such promising process is micro powder injection molding (PIM), which inherits the advantages of the conventional PIM technology, such as low production cost, shape complexity, applicability to many materials, applicability to many materials, and good tolerance. This paper reports on a fundamental investigation of the application of W-Cu powder to micro metal injection molding (MIM), especially in view of achieving a good filling and a safe removal of a micro mold conducted in the experiment. It is absolutely legitimate and meaningful, at the present state of the technique, to continue developing the micro MIM towards production processes for micro components.

• The Journal of the Acoustical Society of Korea
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• v.29 no.2E
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• pp.55-63
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• 2010

High Intensity Focused Ultrasound (HIFU) is a noninvasive surgical method mainly targeting deeply located cancer tissue. Ultrasound is generated from an extemally located transducer and the beam is focused at the target volume, so that selective damage can be achieved without harm to overlying or surrounding tissues. The mechanism for cell killing can be combination of thermal and cavitational damage. Although cavitation can be an effective means of tissue destruction, the possibility of massive hemorrhage and the unpredictable nature of cavitational events prevent clinical application of cavitation. Hence, thermal damage has been a main focus related to HIFU research. 2D phased array transducer systems allow electronic scanning of focus, multi-foci, and anti-focus with multi-foci, so that HIFU becomes more applicable in clinical use. Currently, lack of noninvasive monitoring means of HIFU is the main factor to limit clinical applications, but development in MRI and Ultrasound Imaging techniques may be able to provide solutions to overcome this problem. With the development of advanced focusing algorithm and monitoring means, complete noninvasive surgery is expected to be implemented in the near future.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.25.1-25.4
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• 2018

Background: Some of head and neck cancer patients are in compromised general condition after ablation surgery and chemoradiation therapy, which makes secondary free tissue transfer quite challenging. Elderly cancer patients also have some risk for microvascular surgery with lengthened general anesthesia. In those cases, the pedicled flap vascularized by supraclavicular artery could be considered as an alternative to free flap. Despite several authors have demonstrated the clinical reliability of supraclavicular artery island flap (SCAIF), to date, SCAIF has not been widely used among reconstructive surgeon. In this article, we clarified vascular flow pattern and introduce simple surgical technique of SCAIF with a literature review. Case presentation: Three patients who had underwent previous neck surgery and adjuvant therapy received maxillofacial reconstruction using SCAIF. It required only a few landmarks, flap harvesting was carried out, and the elapsed time gradually decreased to 15 min with experiences. There were no remarkable morbidities in both donor and recipient sites. Conclusion: SCAIF exhibited minimal anatomic variations and short learning curve of surgical techniques, which might be valuable reconstruction modality for beginning surgeon. And it can be beneficial option for the patients with vessel-depleted neck, medically compromised status for lengthened general anesthesia and failed free tissue transfer.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.38-44
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• 2000

In general liquid rocket nozzles are protected from hot combustion gas by regenerative cooling techniques. But due to the complexity of the cooling system, it causes increase of system cost and frequently source of the system malfunction. Recently, instead of regenerative cooing, ablative material are used to protect combustion chamber wall and nozzle. To determine the nozzle material erosion rate and erosion shape, more than 500 hot fire test were performed by using 100 lb thrust experimental liquid rocket. Test variable were propellant feed sequence, injector, position of igniter and liquid oxygen supply temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.873-877
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• 2005

The burr of micro drilling and micro cutting on thin metal film is a major obstacle to mass production for micro PCB boards in micro technologies of personal computing and telecom explosion. As the burr affects on the assembling process, it is necessary to study continuously on control or elimination of the burr. In order to get higher valued products, it is also needed to competitive techniques with the high resolution. In this paper, we studied experimentally the burr generation that when it is processed on the copper foil by laser in micro-hole machining. Unlike mechanical machining the burr produced on substrate is a resultants of melt and re-solidification of a melten metal which was heated and treated by laser. And higher laser energy increases the size of burr. Therefor in micro-drilling with laser, it is difficult to reduce the effects of burr for very thin metal sheets. We investigated the stale of the burr and analyzed the laser ablation Cu micro machining with respect to laser intensity and processing time.

• Archives of Craniofacial Surgery
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• v.22 no.5
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• pp.268-275
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• 2021

Background: The study aimed to evaluate nasal reconstruction techniques customized for Asians. The currently available nasal reconstruction guidelines are based on Caucasian patients, and their applicability is limited in Asian patients due to differences in anatomical and structural features. Methods: A retrospective analysis was performed of the medical records of 76 patients who underwent nasal reconstruction at a single center between January 2010 and June 2020. A comprehensive evaluation was conducted of patients' baseline demographics and clinical characteristics, including age, sex, medical history, defect size and location, reconstructive procedure, pathological diagnosis, postoperative complications, and recurrence. Results: In 59 cases (77%), nasal defects resulted from tumor ablation, and the remaining 17 cases involved post-traumatic (20%) and infection-induced (3%) tissue damage. The most common defect location was the alae, followed by the sidewalls, tip, and dorsum. Forehead flaps were the most commonly used reconstructive technique, followed by nasolabial advancement flaps, rotation flaps, and skin grafts. Each procedure was applied considering aspects of structural anatomy and healing physiology specific to Asians. Complications included nasal deformity, hypertrophic scarring, secondary infection, and partial flap necrosis, but no cases required additional surgical procedures. Tumors recurred in two cases, but tumor recurrence did not significantly affect flap integrity. Conclusion: Nasal reconstruction techniques applied considering Asians' facial features resulted in fewer postoperative complications and higher patient satisfaction than the approaches that are currently in widespread use. Therefore, this study is expected to serve as an essential reference for establishing treatment guidelines for nasal reconstruction in Asians.