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Search Results: 1 - 10 of 197214 matches for " Jung G. Lim "
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Ballistic Behavior of Heracron®-Based Composites: Effect of the Number Multifilaments on High-Speed Projectiles  [PDF]
Jung Seop Lim
Modeling and Numerical Simulation of Material Science (MNSMS) , 2013, DOI: 10.4236/mnsms.2013.33011
Abstract: In this study, two Heracron? woven fabrics, HT840-1 and HT840-2, were fabricated with different multifilament fibers, and their resistance to ballistic impact was investigated. For the same weight and number of plies, the HT840-2 fabric showed improved ballistic properties, compared with HT840-1; this result is contrary to the fiber and fabric properties. With the exception of the yarn’s physical properties, this behavior can be explained in terms of the number of multifilaments, which strongly influenced the ballistic mechanism, i.e., a greater number of multifilament fibers facilitates energy dissipation from a high-speed ballistic projectile. In summary, establishing this optimal number of multifilaments is the key to optimizing the ballistic properties of any given fabric.
Self-Encoded Multiple Access Multiuser Convolutional Codes in Uplink and Downlink Cellular Systems  [PDF]
Jong Hak JUNG, Won Mee JANG, Lim NGUYEN
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.24027
Abstract: Self-encoded spread spectrum eliminates the need for traditional pseudo noise (PN) code generators. In a self-encoded multiple access (SEMA) system, the number of users is not limited by the number of available sequences, unlike code division multiple access (CDMA) systems that employ PN codes such as m-, Gold or Kassami sequences. SEMA provides a convenient way of supporting multi-rate, multi-level grades of service in multimedia communications and prioritized heterogeneous networking systems. In this paper, we propose multiuser convolutional channel coding in SEMA that provides fewer cross-correlations among users and thereby reducing multiple access interference (MAI). We analyze SEMA multiuser convolutional coding in additive white Gaussian noise (AWGN) channels as well as fading channels. Our analysis includes downlink synchronous system as well as asynchronous system such as uplink mobile-to-base station communication.
Significant Reduction of the Microwave Surface Resistance of MgB2 Films by Surface Ion Milling
Sang Young Lee,J. H. Lee,Jung Hun Lee,J. S. Ryu,J. Lim,S. H. Moon,H. N. Lee,H. G. Kim,B. Oh
Physics , 2001, DOI: 10.1063/1.1418026
Abstract: The microwave surface resistance Rs of MgB2 films with the zero-resistance temperature of - 39 K was measured at 8.0 - 8.5 GHz. The MgB2 films were prepared by deposition of boron films on c-cut sapphire, followed by annealing in a vaporized magnesium environment. The Rs appeared significantly reduced by ion milling of the as-grown MgB2 film surface, with the observed Rs of ~ 0.8 mohm at 24 K for an ion-milled MgB2 film as small as 1/15 of the value for the corresponding as-grown MgB2 film. The reduced Rs of the ion-milled MgB2 films is attributed to the effects of the Mg-rich metallic layer existing at the surfaces of the as-grown MgB2 films.
Two Gnaphosid Spiders (Araneae: Gnaphosidae) New to Korean Spider Fauna  [PDF]
Sue Yeon Lee, Seung Tae Kim, Joon-Ho Lee, Jung Sun Yoo, Jong Kook Jung, Jae Won Lim
Open Journal of Animal Sciences (OJAS) , 2014, DOI: 10.4236/ojas.2014.43018
Abstract: Drassyllus yaginumai Kamura, 1987 and Zelotes tortuosus Kamura, 1987 belonging to Gnaphosidae were captured by pitfall trap in maize and soybean fields during the survey of arthropod fauna of agricultural ecosystem in Korea. Present work describes these 2 species with illustrations of taxonomic characters.
Cyanidine-3-O-Galactoside Enriched Aronia melanocarpa Extract Inhibits Adipogenesis and Lipogenesis via Down-Regulation of Adipogenic Transcription Factors and Their Target Genes in 3T3-L1 Cells  [PDF]
Su-Min Lim, Jae In Jung, Nam Young Kim, Jung-Shik Bae, Hyun Sook Lee, Eun Ji Kim
Food and Nutrition Sciences (FNS) , 2019, DOI: 10.4236/fns.2019.102011
Abstract: Aronia melamocarpa (AM) is a rich source of anthocyanins, which are known to help prevent obesity. The cyanidine-3-O-galactoside enriched AM extract (AM-Ex) containing more cyanidine-3-O-galactoside than conventional AM extract was recently developed. The objective of this study was to examine the effect of AM-Ex on adipogenesis and its action mechanisms in vitro using 3T3-L1 adipocytes. To examine the anti-obesity effect of AM-Ex, 3T3-L1 cells were induced adipocyte differentiation and incubated with various concentration of AM-Ex. Lipid accumulation, cellular triglyceride content, mRNA expression of transcription factors and adipogenic genes were analyzed. Treatment with 100 - 400 μg/mL of AM-Ex resulted in a dose-dependent decrease in adipocyte differentiation and triglyceride accumulation. mRNA expression of adipogenic transcription factors, such as peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein α, sterol regulatory element-binding protein 1 were decreased. The level of gene expression of adipogenesis and lipogenesis-related genes, such as adipocyte protein 2, lipoprotein lipase, acetyl-CoA carboxylase, ATP-citrate lyase and fatty acid synthase were decreased. These results suggest that AM-Ex alleviated risk factors related to obesity by modulating multiple pathways associated with adipogenesis.
Parasitic-Element-Loaded UWB Antenna with Band-Stop Function for Mobile Handset Wireless USB
Yohan Lim,Young Joong Yoon,Byungwoon Jung
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/427841
Abstract: A UWB antenna loaded by parasitic elements for wireless USB of mobile handsets is proposed for UWB service in which a band-stop function of 5.725–5.825？GHz WLAN band is required. Two kinds of parasitic elements are incorporated into a rectangular radiator to obtain enhanced impedance bandwidth and band-stop function. The proposed antenna is very compact in size. Wide bandwidths of 3.15–4.75？GHz and 7.2–10.2？GHz are achieved while 5.725–5.825？GHz is notched. Three different shapes of conventional mobile terminals are also considered for measurement. 1. Introduction Ultra-wideband (UWB) antenna technology has been one of the most fascinating design areas in indoor communications, and it has been used with a variety of antennas [1–10]. It has the merits of high-speed transmission rate, low power consumption, and simple hardware configuration over conventional wireless communication systems. The main challenge for UWB antennas is to maintain high performance over a large bandwidth while having small dimensions. Another design concern is that a UWB antenna can allow a potential interference with a wireless local area network (WLAN) [11–13]. Recently, there have been attempts to include UWB systems in USB dongles [14–17]. However, previous UWB antennas for wireless USB devices are too large to be inserted into the terminals of mobile handsets, and interference with the WLAN was not considered in these designs. In this paper, a UWB antenna for wireless USB for mobile handsets is proposed that has both small size and a band-stop function at the upper WLAN band of 5.725–5.825？GHz. Two parasitic elements are used to achieve wideband characteristics and the band-stop function. A tapered and folded feed line is also used to obtain an enhanced impedance matching characteristic [18]. All simulations in this work were carried out using CST Microwave Studio. A design example of the proposed antenna is demonstrated. 2. Antenna Structure The three dimensional configuration of the proposed antenna with its planar figure is shown in Figure 1. A rectangular radiator and parasitic elements are fabricated on the FR4 substrate with a dielectric constant of 4.5 and a height of 1？mm and mounted in the top left-hand corner of a mobile handset board. The optimum design parameters are: AW = 6.4？mm, AL = 6？mm, SL = 4.95？mm, GW = 8？mm, GL = 2.5？mm, BW = 2.6？mm, FL = 7？mm, and FW = 1.5？mm. The size of the radiator is 6.4？mm × 6？mm × 3？mm, and the antenna clearance is 14.4？mm × 16？mm. It has not only very compact size, but also low profile. The PCB size is 35？mm × 80？mm × 1？mm, which
Macro and Microfluidic Flows for Skeletal Regenerative Medicine
Brandon D. Riehl,Jung Yul Lim
Cells , 2012, DOI: 10.3390/cells1041225
Abstract: Fluid flow has a great potential as a cell stimulatory tool for skeletal regenerative medicine, because fluid flow-induced bone cell mechanotransduction in vivo plays a critical role in maintaining healthy bone homeostasis. Applications of fluid flow for skeletal regenerative medicine are reviewed at macro and microscale. Macroflow in two dimensions (2D), in which flow velocity varies along the normal direction to the flow, has explored molecular mechanisms of bone forming cell mechanotransduction responsible for flow-regulated differentiation, mineralized matrix deposition, and stem cell osteogenesis. Though 2D flow set-ups are useful for mechanistic studies due to easiness in in situ and post-flow assays, engineering skeletal tissue constructs should involve three dimensional (3D) flows, e.g., flow through porous scaffolds. Skeletal tissue engineering using 3D flows has produced promising outcomes, but 3D flow conditions (e.g., shear stress vs. chemotransport) and scaffold characteristics should further be tailored. Ideally, data gained from 2D flows may be utilized to engineer improved 3D bone tissue constructs. Recent microfluidics approaches suggest a strong potential to mimic in vivo microscale interstitial flows in bone. Though there have been few microfluidics studies on bone cells, it was demonstrated that microfluidic platform can be used to conduct high throughput screening of bone cell mechanotransduction behavior under biomimicking flow conditions.
Synthesis of a Dual-Labeled Probe of Dimethyl Lithospermate B with Photochemical and Fluorescent Properties
Eunyoung Lim,Jeremy Ricci,Mankil Jung
Molecules , 2011, DOI: 10.3390/molecules16129886
Abstract: Dimethyl lithosermate B (DLB) is a highly potent natural antioxidant and antidiabetic polyphenol with unknown mode of action. To determine its cellular targets, a photochemical and fluorescent dimethyl lithopermate B probe was designed and efficiently synthesized. The dual-labeled chemical probe for biological application was evaluated by UV and fluorescence to determine its electrochemical absorption and emission properties. This probe could be valuable for investigating ligand-protein interactions and subcellular localization.
Induction of G1 and G2/M cell cycle arrests by the dietary compound 3,3'-diindolylmethane in HT-29 human colon cancer cells
Hyun Choi, Do Lim, Jung Park
BMC Gastroenterology , 2009, DOI: 10.1186/1471-230x-9-39
Abstract: HT-29 cells were cultured with various concentrations of DIM (0 – 30 μmol/L) and the DNA was stained with propidium iodide, followed by flow cytometric analysis. [3H]Thymidine incorporation assays, Western blot analyses, immunoprecipitation and in vitro kinase assays for cyclin-dependent kinase (CDK) and cell division cycle (CDC)2 were conducted.The percentages of cells in the G1 and G2/M phases were dose-dependently increased and the percentages of cells in S phase were reduced within 12 h in DIM-treated cells. DIM also reduced DNA synthesis in a dose-dependent fashion. DIM markedly reduced CDK2 activity and the levels of phosphorylated retinoblastoma proteins (Rb) and E2F-1, and also increased the levels of hypophosphorylated Rb. DIM reduced the protein levels of cyclin A, D1, and CDK4. DIM also increased the protein levels of CDK inhibitors, p21CIP1/WAF1 and p27KIPI. In addition, DIM reduced the activity of CDC2 and the levels of CDC25C phosphatase and cyclin B1.Here, we have demonstrated that DIM induces G1 and G2/M phase cell cycle arrest in HT-29 cells, and this effect may be mediated by reduced CDK activity.Epidemiologic data continue to support the hypothesis that the intake of Brassica plants, including turnips, kale, broccoli, cabbage, Brussels sprouts, and cauliflower, may exert protective effects against various types of cancers [1-4]. Dietary glucosinolates present in Brassica species have been previously shown to protect against several types of cancer [5,6]. Indole-3-carbinol (I3C) is the principal hydrolysis product of the glucosinolate glucobrassicin [7], and has been shown to offer significant protection against cancer in animal models induced by a variety of chemical carcinogens [8-10], as well as in cultured human cancer cells [11-13]. Initial clinical trials in women have shown that I3C may prove to be a promising agent against cervical and breast cancers (reviewed in [14]).I3C is chemically unstable in the low pH environment of the stomach, and
Caring for family members with chronic physical illness: A critical review of caregiver literature
Jung-won Lim, Brad Zebrack
Health and Quality of Life Outcomes , 2004, DOI: 10.1186/1477-7525-2-50
Abstract: Recent reforms in U.S. health care systems mean that individuals with long-term, complex health problems are being cared for at home by family members [1]. Specifically, changes in medical practice resulting in shorter impatient hospital stays and the search for outpatient substitutes such as home-based care have brought cost savings to both hospitals and consumers. A study reported that home-based care reduced the cost per patient treated by 44% overall compared with hospital-based treatment [2]. Despite such cost-effectiveness, this trend means that an increased financial, physical, and emotional responsibility falls upon family members who care for a person with chronic physical illness [3]. Now, more than 25 million Americans serve as family caregivers for that population. Their work, if it were part of the market economy, would have an economic value of nearly $257 billion in 2000, which is equal to 20 % of the total for all health-care expenditures [4]. For example, family caregivers are more frequently called upon to use daunting and complex equipment at home. They also deal with extensive coordination of care, including symptom management, disability, mobility, and dressings. In the face of these increasing challenges and responsibilities, caregivers often feel tired, isolated, and overwhelmed, because they lack support, training, information and a sympathetic ear. Furthermore, some family caregivers who are employed report missing work, taking personal days, and quitting or retiring early to provide care [5]. Thus, chronic illness affects not only the lives of those suffering from disease but also those of family members who care for them. Attending to the impacts of chronic illness on family members is important because the physical and emotional health of family caregivers has the potential to influence the health, welfare and successful rehabilitation of persons with such chronic illness [6].Existing studies document how caring for chronically ill family
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