Design rules for a tunable merged-tip microneedle

Lim, Jungeun,Tahk, Dongha,Yu, James,Min, Dal-Hee,Jeon, Noo Li Nature Publishing Group UK 2018 Microsystems & nanoengineering Vol.4 No.-

<▼1><P>This publication proposes the use of an elasto-capillarity-driven self-assembly for fabricating a microscale merged-tip structure out of a variety of biocompatible UV-curable polymers for use as a microneedle platform. In addition, the novel merged-tip microstructure constitutes a new class of microneedles, which incorporates the convergence of biocompatible polymer micropillars, leading to the formation of a sharp tip and an open cavity capable of both liquid trapping and volume control. When combined with biocompatible photopolymer micropillar arrays fabricated with photolithography, elasto-capillarity-driven self-assembly provides a means for producing a complex microneedle-like structure without the use of micromolding or micromachining. This publication also explores and defines the design rules by which several fabrication aspects, such as micropillar dimensions, shapes, pattern array configurations, and materials, can be manipulated to produce a customizable microneedle array with controllable cavity volumes, fracture points, and merge profiles. In addition, the incorporation of a modular through-hole micropore membrane base was also investigated as a method for constitutive payload delivery and fluid-sampling functionalities. The flexibility and fabrication simplicity of the merged-tip microneedle platform holds promise in transdermal drug delivery applications.</P></▼1><▼2><P><B>Drug delivery: self-assembly of microneedles</B></P><P>The fabrication of merged-tip microneedles by elasto-capillarity-driven self-assembly is investigated in photocurable polymers, revealing design parameters for their potential use in drug delivery. Microneedles can be used for delivery of drug payloads by perforating the skin. However, existing needle fabrication processes typically rely on expensive approaches such as etching, embossing, and molding. Now, a team from Seoul National University led by Noo Li Jeon, explore design parameters for fabrication by elastic-capillary-driven self-assembly: photolithography is used to fabricate closely spaced polymer micropillars, the tips of which crosslink to form a microneedle. A number of microneedle geometries are studied, for different UV-curable polymers, suggesting the possibility of their use in drug delivery.</P></▼2>

Cross-linguistic Differences of Temporal Information Processing Between L1 and L2 in Narrative Text Comprehension: An Eye-Tracking Study

JungEun Choi,Moongee Jeon 한국영어학회 2021 영어학 Vol.21 No.-

실시간 승차 공유 알고리즘

이정은(Jungeun Lee),도경민(Kyeong min Do),전정환(Jeong hwan Jeon) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.11

3차원 세포 장벽의 동적의 미세환경을 구축하기 위한 다층구조 플랫폼 개발

임정은(Jungeun Lim),이형록(Stephen Rhee),전누리(Noo Li Jeon) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

Cellular barrier layers play an important role in the body in regulating the diffusion between two microenvironments. Biological barriers such as the blood-brain barrier, blood-cerebrospinal fluid barrier, and the small intestine villi all utilize these epithelial barriers to control the diffusion of solutes into their system. This research describes a method to analyze the effects of microfluidic flow on cellular barriers through the use of a pumpless rocker. A barrier layer was recapitulated using brain epithelial cells cultured on a 3D-printed mesh platform, and a rocker system was used to induce microfluidic flow within the system. This study can provide insight into the mechanisms and effects of microfluidic flow on epithelial barriers for future studies.

Cooperative Sensing Protocol for Cognitive Radio

Hyoungsuk Jeon,Sunghun Kim,Jungeun Kim,Joongsoo Ma,Hyuckjae Lee 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

As the wireless communication services grow quickly, the seriousness of spectrum scarcity has been on the rise gradually. The cognitive radio (CR), an emerging technology, has been come out to solve today’s spectrum scarcity. In this paper, we focus on spectrum sensing part, the most critical part in the CR, and propose the notification protocol to exchange sensing information efficiently. It is designed to avoid overlapped information by inserting broadcast phases. Hence, it makes possible to dynamically coordinate sensing period in the CR network. The simulation result shows that required packets of proposed protocol are not directly proportional to the number of CR nodes even in the large network.

A Study on Performance Analysis of V2V Communication Based AEB System Considering Road Friction at Slopes

Sangduck Jeon,Jungeun Lee,Byeongwoo Kim 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.11

An autonomous emergency braking (AEB) system based on Vehicle to Vehicle (V2V) communication considering road friction at slopes was proposed in this study. Conventional AEB systems have limited performance of effective braking according to road conditions because they mostly consider only particular road conditions on straight roads. To solve this limitation, a new control logic was proposed to calculate the braking timing by considering road condition at slopes. The TTC (time to collision) method, which is the collision risk, was introduced in the proposed AEB system based on information of the host vehicle and a nearby vehicle. To verify the proposed AEB system, various road conditions, vehicle speeds and slopes were reflected in this scenario. The AEB system proposed through this analysis showed enhanced braking and collision avoidance performances compared to conventional AEB systems.

Extramammary Paget’s disease of the vulva : The clinicopathological characteristics, treatment, and outcomes in a study of 43 cases

( Suin Yoon ),( Jungeun Jeon ),( Jihee Jung ),( Jeong Won Lee ) 대한산부인과학회 2022 대한산부인과학회 학술대회 Vol.108 No.-

Objective: Extramammary Pagets disease (EMPD) is a rare tumor that commonly affects the vulva in postmenopausal women. Due to its low incidence, there is a lack of information on the clinical manifestation and treatment outcomes of EMPD. The objective of the current study was to analyze the clinicopathologic features, treatment, and outcome of patients with primary EMPD of the vulva. Methods: We conducted a retrospective review of 43 patients with EMPD of the vulva from Jaunary 2003 to January 2022 at a single institution. Results: The mean age of the patients was 64.3 years (range, 50-78). Among 43 patients, 27 (62.8%) patients were diagnosed with intraepithelial EMPD, and 16 (37.2%) patients were diagnosis with invasive EMPD. Surgical treatment were performed in all patients. 29 (67.4%) patients underwent wide local excision, 8 (18.6%) patients received simple vuvlectomy, and 6 (14.0%) patients received radical vulvectomy. 10 patients underwent postoperative radiotherapy due to a positive surgical margin and clinically suspected residual tumor. After a median follow-up of 38.4 months (range, 2 to 132 months), recurrence was observed in 9 (20.9%). The modalities of treatment, either surgery alone or surgery with radiotherapy, and the type of surgery were not related to the recurrence. Furthermore, there was no association between disease recurrence and surgical margin status. The 4-year tumor free rates were 51.5% for surgical margin positive tumors and 85.6% for surgical margin negative tumors. 9 (52.9%) of the 17 patients who had positive surgical margin received postoperative radiotherapy, and 2 (22.2%) patients developed recurrent disease, whereas 7 (77.8%) patients are disease-free. Conclusion: Surgical excision is the established standard treatment for EMPD, and positive margins are common finding after surgery. Although local recurrence is frequent regardless of the treatment modalities and margin status, postoperative radiotherapy may be a strategy to treat EMPD with positive surgical margins.

From microchannels to microphysiological systems: Development of application specific devices

Yu, James,Lim, Jungeun,Choi, MunSeok,Chung, Minhwan,Jeon, Noo Li Elsevier 2018 MICROELECTRONIC ENGINEERING Vol.202 No.-

<P><B>Abstract</B></P> <P>Microphysiological systems are an emerging field of biomimetic technologies which utilize microfluidics to reconstitute tissue functions within an <I>in vitro</I> environment. Microfluidic organ-on-a-chip platforms exist at the intersection of biology and engineering, straddling the forefront of cutting edge biological research, fluidics, and microfabrication technologies to emulate complex <I>in vitro</I> tissue systems within a highly controllable, accessible, and observable, <I>in vitro</I> environment. Although the advance of cell culture technologies from comparatively rudimentary conventional 2D petri dish based cultures to sophisticated 3D tissue engineering may seem futuristic, the microfluidic engineering concepts behind organ-on-a-chip technologies have deep historical roots which span over half a century. In this paper, we will discuss the shortcomings of conventional cell culture and organ modeling platforms which contributed to the demand for <I>in vitro</I> tissue engineering, as well as provide a background in the technological foundations of microfluidics. We will further recount a brief history of microfluidic cell culture, with emphasis on important developments in fabrication practices and methods of engineering biologically relevant microenvironmental conditions, before discussing the present state of organ specific microfluidic platforms and the future directions that the field may take to overcome present challenges.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of AZT-based cationic lipids and <i>in vitro</i> evaluation of siRNA delivery

Park, Sun Min,Woo, Jungeun,Jeon, Eunmi,Kim, Byeang Hyean Royal Society of Chemistry 2010 Chemical communications Vol.46 No.9

<P>New types of cationic lipids based on AZT were evaluated for their biological effects in terms of their cytotoxicity and their cellular delivery of siRNA.</P> <P>Graphic Abstract</P><P>New types of cationic lipids based on AZT were evaluated for their biological effects in terms of their cytotoxicity and their cellular delivery of siRNA. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b919845h'> </P>

Initial good response to neoadjuvant chemotherapy was not related to survival benefit of ovarian cancer in the maintenance therapy era

( Young Joo Lee ),( Jungeun Jeon ),( Yoon Kyung Shin ),( Nae Ri Kim ),( Se Ik Kim ),( Yoo-young Lee ),( Jeong-yeol Park ),( Jae-weon Kim ),( Hyun-woong Cho ),( Jung-yun Lee ) 대한산부인과학회 2022 대한산부인과학회 학술대회 Vol.108 No.-

Objective: The aim of the study is to re-validate CRS as a prognostic factor for ovarian cancer patients who received front-line maintenance therapy or intra-operative chemotherapy. Methods: The retrospective analysis was performed with the medical records from tubo-ovarian high grade serous carcinoma patients who received neoadjuvant chemotherapy followed by interval debulking surgery between January 2007 to December 2021 at five tertiary medical institutions in South Korea. Progression-free survival (PFS) and overall survival (OS) were obtained using Kaplan-Meier analysis; the aforementioned was used to evaluate the effect of BRCA mutation, Poly-ADP Ribose Polymerase (PARP) inhibitor, bevacizumab, hyperthermic intraperitoneal chemotherapy (HIPEC), and CRS. Results: A total 549 patients were analyzed. BRCA 1/2 mutations were detected in 178(32.4%) patients and 117(21.3%) patients were treated with PARP inhibitors, and 57(10.4%) patients were treated with bevacizumab as a front-line maintenance therapy. CRS3 in patients with BRCA wildtype was associated with improved PFS (25.9 vs 15.2 months, p<0.001) compared to CRS 1 or 2. However, there is no significant PFS prolongation of CRS3 in patients with BRCA mutation compared to CRS 1 or 2 (22.0 vs 19.3 months, p=0.17). In addition, CRS3 in PARP inhibitors-naive patients improved PFS significantly longer than CRS 1 or 2 (24.7 vs 15.5 months, p<0.001), whereas CRS3 in patients with PARP inhibitors as a front-line maintenance therapy were not significantly associated with prolongation of PFS (24.3 vs 22.4, p=0.85). Similarly, in opposition to bevacizumab-naïve patients, no statistically significant PFS prolongation of CRS3 was revealed compared to CRS1 or 2 in patients with front-line bevacizumab maintenance therapy (27.5 vs 17.5 months, p=0.202). Conclusion: Contrary to previous research, the CRS system may not be a prognostic factor in patients affected by BRCA mutation or treated with front-line maintenance therapy such as PARP inhibitors or bevacizumab.