Timely assessment of infarct volume and brain atrophy in acute hemispheric infarction for early surgical decompression: strict cutoff criteria with high specificity.

Park, Jaechan,Goh, Duck-Ho,Sung, Joo-Kyung,Hwang, Yang-Ha,Kang, Dong-Hun,Kim, Yongsun Springer-Verlag 2012 Acta neurochirurgica Vol.154 No.1

<P>For a large hemispheric infarction, the clinical decision for decompressive surgery is commonly made on the basis of both radiological data showing brain swelling with herniation and concomitant neurological deterioration. However, for early decompressive surgery before clinical deterioration, strict cutoff criteria with a high specificity are required on the basis of timely assessment of the infarct volume.</P>

Surgical Informed Consent Process in Neurosurgery

Park, Jaechan,Park, Hyojin The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.4

The doctrine of informed consent, as opposed to medical paternalism, is intended to facilitate patient autonomy by allowing patient participation in the medical decision-making process. However, regrettably, the surgical informed consent (SIC) process is invariably underestimated and reduced to a documentary procedure to protect physicians from legal liability. Moreover, residents are rarely trained in the clinical and communicative skills required for the SIC process. Accordingly, to increase professional awareness of the SIC process, a brief history and introduction to the current elements of SIC, the obstacles to patient autonomy and SIC, benefits and drawbacks of SIC, planning of an optimal SIC process, and its application to cases of an unruptured intracranial aneurysm are all presented. Optimal informed consent process can provide patients with a good comprehension of their disease and treatment, augmented autonomy, a strong therapeutic alliance with their doctors, and psychological defenses for coping with stressful surgical circumstances.

Blood Blister-Like Aneurysm with Rupture Point Close to Origin of Anterior Choroidal Artery

Park, Jaechan The Korean Neurosurgical Society 2014 Journal of Korean neurosurgical society Vol.56 No.6

If a ruptured blood blister-like aneurysm (BBA) arises from the lateral or superolateral wall of the internal carotid artery (ICA) at the level of the anterior choroidal artery (AChA), its proximity to the origin of the AChA presents a serious surgical challenge to preserve the patency of the AChA. Two such rare cases are presented, along with successful surgical techniques, including the application of a C-shaped aneurysm clip parallel to the ICA and a microsuture technique to repair the arterial defect. The patency of the AChA and ICA was successfully preserved without recurrence or rebleeding of the BBA during a 1-year follow-up after the operation.

Diagnostic usefulness of intraoperative ultrasonography for unexpected severe brain swelling in ultra-early surgery for ruptured intracranial aneurysms.

Park, Jaechan,Woo, Hyunjin,Kim, Gab Chul Springer-Verlag 2012 Acta neurochirurgica Vol.154 No.10

<P>In ultra-early aneurysm surgery, the few hours from admission to aneurysm clipping present the greatest risk for an in-hospital recurrent hemorrhage, the development of acute hydrocephalus, and severe brain edema. Thus, severe brain swelling encountered after dural opening in a craniotomy can sometimes not be explained by a preoperative computed tomography (CT) scan. Therefore, neurosurgeons need a diagnostic tool to determine the exact cause of the brain swelling to apply appropriate intraoperative management. Accordingly, the authors propose a designated optimal ultrasound window for evaluating brain swelling during a pterional craniotomy, and assess its diagnostic usefulness and clinical impact.</P>

Pterional or Subfrontal Access for Proximal Vascular Control in Anterior Interhemispheric Approach for Ruptured Pericallosal Artery Aneurysms at Risk of Premature Rupture

Park, Jaechan The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.2

Objective : Cases of a ruptured pericallosal artery aneurysm with a high risk of intraoperative premature rupture and technical difficulties for proximal vascular control require a technique for the early and safe establishment of proximal vascular control. Methods : A combined pterional or subfrontal approach exposes the bilateral A1 segments or the origin of the ipsilateral A2 segment of the anterior cerebral artery (ACA) for proximal vascular control. Proximal control far from the ruptured aneurysm facilitates tentative clipping of the rupture point of the aneurysm without a catastrophic premature rupture. The proximal control is then switched to the pericallosal artery just proximal to the aneurysm and its intermittent clipping facilitates complete aneurysm dissection and neck clipping. Results : Three such cases are reported : a ruptured pericallosal artery aneurysm with a contained leak of the contrast from the proximal side of the aneurysm, a low-lying ruptured pericallosal artery aneurysm with irregularities on its proximal wall, and a multilobulated ruptured pericallosal artery aneurysm with the parasagittal bridging veins hindering surgical access to the proximal parent artery. In each case, the proposed combined pterional-interhemispheric or subfrontal-interhemispheric approach was successfully performed to establish proximal vascular control far from the ruptured aneurysm and facilitated aneurysm clipping via the interhemispheric approach. Conclusion : When using an anterior interhemispheric approach for a ruptured pericallosal artery aneurysm with a high risk of premature rupture, a pterional or subfrontal approach can be combined to establish early proximal vascular control at the bilateral A1 segments or the origin of the A2 segment.

Superciliary Keyhole Approach for Unruptured Anterior Circulation Aneurysms : Surgical Technique, Indications, and Contraindications

Park, Jaechan The Korean Neurosurgical Society 2014 Journal of Korean neurosurgical society Vol.56 No.5

Neurosurgeons have been trying to reduce surgical invasiveness by applying minimally invasive keyhole approaches. Therefore, this paper clarifies the detailed surgical technique, its limitations, proper indications, and contraindications for a superciliary keyhole approach as a minimally invasive modification of a pterional approach. Successful superciliary keyhole surgery for unruptured aneurysms requires an understanding of the limitations and the use of special surgical techniques. Essentially, this means the effective selection of surgical indications, usage of the appropriate surgical instruments with a tubular shaft, and refined surgical techniques, including straightforward access to the aneurysm, clean surgical dissection, and the application of clips with an appropriate configuration. A superciliary keyhole approach allows unruptured anterior circulation aneurysms to be clipped safely, rapidly, and less invasively on the basis of appropriate surgical indications.

Time-dependent changes in lipid metabolism in mice with methionine choline deficiency-induced fatty liver disease

Park, Han-Sol,Jeon, Byeong Hwan,Woo, Sung Hoon,Leem, Jaechan,Jang, Jung Eun,Cho, Min Sock,Park, In-Sun,Lee, Ki-Up,Koh, Eun Hee Springer-Verlag 2011 Molecules and cells Vol.32 No.6

Dynamics of Global Catch-up Process in Shipbuilding Industry: A Case of Hyundai Heavy Industries

Jaechan Park,Taewoo Roh 한국국제경영관리학회 2014 국제경영리뷰 Vol.18 No.4

본 연구는 조선산업에서 오랜 기간 1등을 유지한 현대중공업의 성공요인과 중국 조선 기업들의 글로벌 추격, 그리고 이러한 중국 기업들의 추격에 대한 현대중공업의 대응전략을 살펴보았다. 우선, 조선 산업의 역사적 흐름을 이해하고 한국 조선기업들이 일본 조선기업들을 추월하게 된 성공요인, 그리고 최근 중국 조선 기업들의 성장에 대한 배경을 기술하였다. 현대중공업은 조선 산업에 진출했을 때, 초기 정부의 지원으로 원가경쟁력을 가지고 시장을 선도한 뒤 곧이어 뛰어난 기술력을 바탕으로 세계 1위 기업으로 성장하였다. 하지만, 2000년대에 들어서면서 중국 조선 기업들은 정부의 강력한 지원 아래 세계 조선 시장의 시장점유율을 급속도로 장악하고 있다. 세계 1위를 고수하고 있던 현대중공업은 신규 수주량 및 잔고주문량의 상당부분을 중국 기업들에게 빼앗기게 되면서 기존의 지배적인 경쟁력이 흔들리기 시작했다. 본 연구에서는 세계 조선산업에서 오랜 기간 동안 시장을 선도한 현대중공업의 성공요인을 고찰하고, 최근에 진출한 비조선산업분야에 대한 분석을 실시하여 조선산업에서의 다각화 전략에 관한 시사점을 도출하고자 하였다. 첫째, 현대중공업의 글로벌 경쟁력은 중국 조선업체들에 비해 여전히 우위에 있다고 볼 수 있다. 현대중공업은 처음 조선 산업에 진출했을 때, 저원가 전략으로 성공했지만 곧바로 기술적 차별화를 통해 글로벌 시장에서 수주량을 획득한 반면, 중국 조선업체들은 자국 내 수주량에 상당히 의존적이기 때문에 글로벌 경쟁력은 상대적으로 미흡하다고 볼 수 있다. 둘째, 고부가가치선의 수주에 있어서도 여전히 현대중공업의 입지는 견고하다고 볼 수 있다. 셋째, 비조선산업으로의 진출은 고부가가치선에서 창출되는 역량을 보완할 수 있는 것으로 사료된다. 본 연구에서는 추가적으로 허핀달 지수와 관련/비관련 다각화 지수 등을 이용해 현대중 공업이 선택한 비조선산업으로의 다각화를 평가해 보았으며, 비조선산업으로의 다각화전략은 글로벌 시장에서 선박 수주의 주기적 불확실성을 낮추는 역할을 하는 것으로 나타났다. This study aims to identify the dynamic process by which shipbuilding companies keep up with competitors. The Korean shipbuilding companies have transformed themselves from cheap imitators of Japanese shipbuilders into the world’s most competitive shipbuilding powerhouses. As an example of this phenomenon, Hyundai Heavy Industries has developed into one of the world's leading shipbuilding and offshore contractors in terms of advanced information technologies, systematized shipbuilding technologies, and a vast quantity of large plant and offshore structure management experience. However, as Korean shipbuilders’ cost advantages are eventually eroded away through competition, the question remains whether fast-growing Chinese shipbuilders as late-movers pose a threat to Hyundai Heavy Industries. To answer the question, this research focuses on success factors of which Hyundai Heavy Industries can take up the lead in shipbuilding industry and confrontational strategies to the chase of Chinese shipbuilders by using SWOT analysis.

Preoperative percutaneous mapping of the frontal branch of the facial nerve to assess the risk of frontalis muscle palsy after a supraorbital keyhole approach

Park, Jaechan,Jung, Tae-du,Kang, Dong-Hun,Lee, So-Hyun Journal of Neurosurgery Publishing Group 2013 Journal of Neurosurgery Vol.118 No.5

<B>Object</B><P>Although a supraorbital keyhole approach utilizing an eyebrow incision and supraorbital minicraniotomy is one of the most commonly used keyhole approaches for treating cerebral aneurysms, the risk of frontalis muscle palsy due to an injury of the frontal branch of the facial nerve remains a serious drawback to a supraorbital keyhole approach as a minimally invasive surgical technique. Therefore, the authors attempted to evaluate the risk of frontalis muscle palsy by mapping the frontal nerve branch in the lower forehead using a nerve conduction study in individual patients.</P><B>Methods</B><P>Percutaneous mapping of the frontal nerve branch was performed preoperatively on 52 patients who underwent supraorbital keyhole approaches for aneurysmal clipping. The maximal compound muscle action potentials (CMAPs) in the lower forehead were observed at 5 points along a laterally inclined line angled 30° from the midpupillary line, in which the points were 1.0, 1.5, 2.0, 2.5, and 3.0 cm as measured from the supraorbital margin.</P><B>Results</B><P>Severe frontalis muscle palsy was observed in 11 patients (21.2%), yet recovery occurred 2-5 months after surgery. No patients experienced permanent palsy. The incidence of severe palsy was 7.4% in those patients showing clear CMAPs with a high location (exclusively at 2.0, 2.5, or 3.0 cm), 14.3% in those with a bimodal distribution, 40.0% in those with a low location (exclusively at 1.5 cm), and 83.3% in those with an extremely low location (exclusively at 1.0 cm).</P><B>Conclusions</B><P>Percutaneous mapping of the frontal branch of the facial nerve using a nerve conduction study can be used to assess the risk of postoperative frontalis muscle palsy following a supraorbital keyhole approach. The patients with the highest risk of postoperative palsy showed a clear CMAP exclusively at 1.0 cm along the inclined line measured from the supraorbital margin.</P>

A Study on the Uncertainty of Radiochronometry Based on Bateman Equation

JaeChan Park,TaeHoon Jeon,JungHo Song,MinSu Ju,KiNam Kwon,WooCheol Choi,JinYoung Chung 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Nuclear Forensics is recognized as a essential component in the nuclear non-proliferation verification sector by the international community. It is being advanced under the leadership of the IAEA, the U.S., and the EU. Both the U.S.’s Lawrence Livermore National Laboratory (LLNL) and the international collaborative organization, the Nuclear Forensics International Technical Working Group (ITWG), have proposed to establish a relationship between the production timing and radiochronometry of nuclear materials or samples to utilize in the field of nuclear forensics. Radiochronometry of nuclear materials is calculated based on the Bateman equation, incorporating factors with uncertainties derived from tests, experiments, and analyses. The results from the nuclear activity radiochronometry also encompass uncertainties, affecting their reliability. This study examined the mathematical uncertainty calculations related to the results of nuclear activity radiochronometry, focusing on calculation methods, contribution rates per factor, and sensitivities. Uncertainty factors for the Bateman equation-based radiochronometry were observed in the decay constants for each nuclide type and the uncertainty in the radioactive ratio of the tracer nuclide. The sensitivity for each factor revealed that the uncertainty in the radioactive ratio of the signature nuclide contributed more significantly than the uncertainty in decay constants for each nuclide type. Each factor displayed a distinct sensitivity curve relative to the radioactive ratio. As it approaches a radioactive equilibrium, the sensitivity tends to increase infinitely, indicating a corresponding trend of infinite increase in uncertainty. Because the time and curve shape to reach radioactive equilibrium vary depending on the signature nuclide, it’s essential to choose an appropriate signature nuclide based on the anticipated period and analysis requirements for nuclear activity radiochronometry. However, radiochronometry using mathematical methods is limited to the relationship between parent and daughter nuclides, presenting the potential for underestimation of uncertainty factors like decay constants. Future research will need to focus on uncertainty calculation methods through computational simulations, especially using the Monte Carlo method, to overcome the limitations of mathematical approaches and potential underestimations.