Kyungpook National University

About: Kyungpook National University is a education organization based out in Daegu, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 20497 authors who have published 42107 publications receiving 834608 citations.

DFR: Directional flooding-based routing protocol for underwater sensor networks

Abstract: Unlike terrestrial sensor networks, underwater sensor networks (UWSNs) have different characteristics such as a long propagation delay, a narrow bandwidth and high packet loss. Hence, existing path setup-based routing protocols proposed for terrestrial sensor networks are not applicable in the underwater environment. For example, they take much time when establishing a path between source and destination nodes due to the long propagation delay. In addition, the path establishment requires much overhead of control messages. Moreover, the dynamic and high packet loss degrades reliability, which invokes more retransmissions. Even though exiting routing protocols such as VBF were proposed to improve the reliability, they did not take into account the link quality. That is, there is no guarantee that packets reach the sink safely especially when a link is error-prone. In this paper, we therefore propose a directional flooding-based routing protocol, called DFR. Basically, DFR relies on a packet flooding technique to increase the reliability. However, the number of nodes which flood a packet is controlled in order to prevent a packet from flooding over the whole network and the nodes to forward the packet are decided according to the link quality. In addition, DFR also addresses a well-known void problem by allowing at least one node to participate in forwarding a packet. Our simulation study using ns-2 proves that DFR is more suitable for UWSNs especially when links are prone to packet loss.

First exploration of parasitoids of Drosophila suzukii in South Korea as potential classical biological agents

Abstract: The invasive spotted wing drosophila, Drosophila suzukii Matsumura (Dipt.: Drosophilidae), a native of East Asia, has widely established in North America and Europe, where it is a serious pest of small and stone fruit crops. The lack of effective indigenous parasitoids of D. suzukii in the recently colonized regions prompted the first foreign exploration for co-evolved parasitoids in South Korea during 2013 and 2014. We collected the larval parasitoids Asobara japonica Belokobylskij, A. leveri (Nixon) and A. brevicauda Guerrieri & van Achterberg (Hym.: Braconidae), Ganaspis brasiliensis (Ihering), Leptopilina japonica japonica Novkovic & Kimura and L. j. formosana Novkovic & Kimura (Hym.: Figitidae); and the pupal parasitoids Pachycrepoideus vindemiae (Rondani) (Hym.: Pteromalidae) and Trichopria drosophilae Perkins (Hym.: Diapriidae). From UC Berkeley quarantine records, percentage parasitism ranged from 0 to 17.1 % and varied by geography, season, and collection methods. Asobara japonica was the most common parasitoid species. Higher numbers of parasitoids were reared from field-picked fruit as opposed to traps baited with uninfested fruit. Quarantine bioassays confirmed that A. japonica, G. brasiliensis, L. j. japonica, P. vindemiae, and T. drosophilae developed from D. suzukii. Female individuals of the endoparasitoid, A. japonica, were larger when reared on the larger D. suzukii larvae compared with those reared on the smaller larvae of D. melanogaster Meigen. Larger parasitoid size was associated with longer developmental time. Several of the South Korean parasitoid species have the potential for use in classical biological control and may contribute to the suppression of D. suzukii in the newly invaded regions.

Identification of Developmental Endothelial Locus-1 on Circulating Extracellular Vesicles as a Novel Biomarker for Early Breast Cancer Detection.

Abstract: Purpose Currently, there are no molecular biomarkers for the early detection of breast cancer (BC). This study focused on identifying surface proteins found on circulating extracellular vesicles (EVs) for detecting early-stage BC. Experimental Design Circulating EVs, isolated from the plasma of 10 patients with BC (stages I and II), and 5 healthy controls, were analyzed using LC-MS/MS. Developmental endothelial locus-1 protein (Del-1) was selected as a candidate biomarker. Two different enzyme-linked immunosorbent assays (ELISAs) were used to measure Del-1 in plasma samples from healthy controls (n = 81), patients with BC (n = 269), BC patients after surgical resection (n = 50), patients with benign breast tumors (n = 64), and patients with non-cancerous diseases (n = 98), in two cohorts. Results Plasma Del-1 levels were significantly higher (P < 0.0001) in patients with BC than in all controls and returned to almost normal after tumor removal. The diagnostic accuracy of Del-1 was area under the curve (AUC), 0.961 [95% CI, 0.924-0.983], sensitivity of 94.70% and specificity of 86.36% in test cohort, and 0.968 [0.933-0.988], 92.31% and 86.62% in validation cohort for early-stage BC by one type of ELISA. Furthermore, Del-1 maintained diagnostic accuracy for patients with early-stage BC using the other type of ELISA (0.946 [0.905-0.972], 90.90%, and 77.14% in the test cohort; 0.943 [0.900-0.971], 89.23%, and 80.99% in the validation cohort). Conclusions Del-1 on circulating EVs is a promising marker to improve identification of patients with early-stage BC and distinguish BC from benign breast tumors and non-cancerous diseases.

A Dual Role of Lipocalin 2 in the Apoptosis and Deramification of Activated Microglia

Abstract: Activated microglia are thought to undergo apoptosis as a self-regulatory mechanism. To better understand molecular mechanisms of the microglial apoptosis, apoptosis-resistant variants of microglial cells were selected and characterized. The expression of lipocalin 2 (lcn2) was significantly down-regulated in the microglial cells that were resistant to NO-induced apoptosis. lcn2 expression was increased by inflammatory stimuli in microglia. The stable expression of lcn2 as well as the addition of rLCN2 protein augmented the sensitivity of microglia to the NO-induced apoptosis, while knockdown of lcn2 expression using short hairpin RNA attenuated the cell death. Microglial cells with increased lcn2 expression were more sensitive to other cytotoxic agents as well. Thus, inflammatory activation of microglia may lead to up-regulation of lcn2 expression, which sensitizes microglia to the self-regulatory apoptosis. Additionally, the stable expression of lcn2 in BV-2 microglia cells induced a morphological change of the cells into the round shape with a loss of processes. Treatment of primary microglia cultures with the rLCN2 protein also induced the deramification of microglia. The deramification of microglia was closely related with the apoptosis-prone phenotype, because other deramification-inducing agents such as cAMP-elevating agent forskolin, ATP, and calcium ionophore also rendered microglia more sensitive to cell death. Taken together, our results suggest that activated microglia may secrete LCN2 protein, which act in an autocrine manner to sensitize microglia to the self-regulatory apoptosis and to endow microglia with an amoeboid form, a canonical morphology of activated microglia in vivo.

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

Abstract: . We present the organization, instrumentation, datasets, data interpretation, modeling, and accomplishments of the multinational global atmospheric measurement program AGAGE (Advanced Global Atmospheric Gases Experiment). AGAGE is distinguished by its capability to measure globally, at high frequency, and at multiple sites all the important species in the Montreal Protocol and all the important non-carbon-dioxide (non- CO2 ) gases assessed by the Intergovernmental Panel on Climate Change ( CO2 is also measured at several sites). The scientific objectives of AGAGE are important in furthering our understanding of global chemical and climatic phenomena. They are the following: (1) to accurately measure the temporal and spatial distributions of anthropogenic gases that contribute the majority of reactive halogen to the stratosphere and/or are strong infrared absorbers (chlorocarbons, chlorofluorocarbons – CFCs, bromocarbons, hydrochlorofluorocarbons – HCFCs, hydrofluorocarbons – HFCs and polyfluorinated compounds (perfluorocarbons – PFCs), nitrogen trifluoride – NF3 , sulfuryl fluoride – SO2F2 , and sulfur hexafluoride – SF6 ) and use these measurements to determine the global rates of their emission and/or destruction (i.e., lifetimes); (2) to accurately measure the global distributions and temporal behaviors and determine the sources and sinks of non- CO2 biogenic–anthropogenic gases important to climate change and/or ozone depletion (methane – CH4 , nitrous oxide – N2O , carbon monoxide – CO, molecular hydrogen – H2 , methyl chloride – CH3Cl , and methyl bromide – CH3Br ); (3) to identify new long-lived greenhouse and ozone-depleting gases (e.g., SO2F2 , NF3 , heavy PFCs ( C4F10 , C5F12 , C6F14 , C7F16 , and C8F18 ) and hydrofluoroolefins (HFOs; e.g., CH2 = CFCF3 ) have been identified in AGAGE), initiate the real-time monitoring of these new gases, and reconstruct their past histories from AGAGE, air archive, and firn air measurements; (4) to determine the average concentrations and trends of tropospheric hydroxyl radicals (OH) from the rates of destruction of atmospheric trichloroethane ( CH3CCl3 ), HFCs, and HCFCs and estimates of their emissions; (5) to determine from atmospheric observations and estimates of their destruction rates the magnitudes and distributions by region of surface sources and sinks of all measured gases; (6) to provide accurate data on the global accumulation of many of these trace gases that are used to test the synoptic-, regional-, and global-scale circulations predicted by three-dimensional models; and (7) to provide global and regional measurements of methane, carbon monoxide, and molecular hydrogen and estimates of hydroxyl levels to test primary atmospheric oxidation pathways at midlatitudes and the tropics. Network Information and Data Repository: http://agage.mit.edu/data or http://cdiac.ess-dive.lbl.gov/ndps/alegage.html ( https://doi.org/10.3334/CDIAC/atg.db1001 ).