Quadratic Derivations on non-Archimedean Banach Algebras

Park, C.,Shagholi, S.,Javadian, A.,Savadkouhi, M.B.,Gordji, M.E. Eudoxus Press LLC 2014 Journal of computational analysis and applications Vol.16 No.3

Let A be an algebra and X be an A-module. A quadratic mapping D : A X is called a quadratic derivation ifD(ab) = D(a)b(2) + a(2) D(b)for all a(1), a(2) is an element of A. We investigate the Hyers-Ulam stability of quadratic derivations from a non-Archimedean Banach algebra A into a non-Archimedean Banach A-module.

Restricted growth of U‐type infectious haematopoietic necrosis virus (IHNV) in rainbow trout cells may be linked to casein kinase II activity

Park, J W,Moon, C H,Harmache, A,Wargo, A R,Purcell, M K,Bremont, M,Kurath, G Blackwell Publishing Ltd 2011 Journal of fish diseases Vol.34 No.2

<P><B>Abstract</B></P><P>Previously, we demonstrated that a representative M genogroup type strain of infectious haematopoietic necrosis virus (IHNV) from rainbow trout grows well in rainbow trout‐derived RTG‐2 cells, but a U genogroup type strain from sockeye salmon has restricted growth, associated with reduced genome replication and mRNA transcription. Here, we analysed further the mechanisms for this growth restriction of U‐type IHNV in RTG‐2 cells, using strategies that assessed differences in viral genes, host immune regulation and phosphorylation. To determine whether the viral glycoprotein (G) or non‐virion (NV) protein was responsible for the growth restriction, four recombinant IHNV viruses were generated in which the G gene of an infectious IHNV clone was replaced by the G gene of U‐ or M‐type IHNV and the NV gene was replaced by NV of U‐ or M‐type IHNV. There was no significant difference in the growth of these recombinants in RTG‐2 cells, indicating that G and NV proteins are not major factors responsible for the differential growth of the U‐ and M‐type strains. Poly I:C pretreatment of RTG‐2 cells suppressed the growth of both U‐ and M‐type IHNV, although the M virus continued to replicate at a reduced level. Both viruses induced type 1 interferon (IFN1) and the IFN1 stimulated gene Mx1, but the expression levels in M‐infected cells were significantly higher than in U‐infected cells and an inhibitor of the IFN1‐inducible protein kinase PKR, 2‐aminopurine (2‐AP), did not affect the growth of U‐ or M‐type IHNV in RTG‐2 cells. These data did not indicate a role for the IFN1 system in the restricted growth of U‐type IHNV in RTG‐2 cells. Prediction of kinase‐specific phosphorylation sites in the viral phosphoprotein (P) using the NetPhosK program revealed differences between U‐ and M‐type P genes at five phosphorylation sites. Pretreatment of RTG‐2 cells with a PKC inhibitor or a p38MAPK inhibitor did not affect the growth of the U‐ and M‐type viruses. However, 100 μ<SMALL>m</SMALL> of the casein kinase II (CKII) inhibitor, 5,6‐dichloro‐1‐β‐<SMALL>d</SMALL>‐ribofuranosylbenzimidazole (DRB), reduced the titre of the U type 8.3‐fold at 24 h post‐infection. In contrast, 100 μ<SMALL>m</SMALL> of the CKII inhibitor reduced the titre of the M type only 1.3‐fold at 48 h post‐infection. Our data suggest that the different growth of U‐ and M‐type IHNV in RTG‐2 cells may be linked to a differential requirement for cellular protein kinases such as CKII for their growth.</P>

Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

Won, M,Park, K A,Byun, H S,Sohn, K-C,Kim, Y-R,Jeon, J,Hong, J H,Park, J,Seok, J H,Kim, J M,Yoon, W-H,Jang, I-S,Shen, H M,Liu, Z G,Hur, G M Macmillan Publishers Limited 2010 CELL DEATH AND DIFFERENTIATION Vol.17 No.12

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

Calcium nitrate (Ca(NO₃)₂)-based inorganic salt electrode for supercapacitor with long-cycle life performance

Cho, S.,Han, J.,Kim, J.,Jo, Y.,Woo, H.,Lee, S.,Aqueel Ahmed, A.T.,Chavan, H.C.,Pawar, S.M.,Gunjakar, J.L.,Kwak, J.,Park, Y.,Inamdar, A.I.,Kim, H.,Kim, H.,Im, H. ELSEVIER 2017 Current Applied Physics Vol.17 No.9

<P>A novel water-soluble inorganic Ca(NO3)(2) salt electrode is investigated for its pseudocapacitance in an aqueous KOH electrolyte. Commercially available Ca(NO3)(2) salt is directly used as the key electrode material. The supercapacitor electrode contains Ca(NO3)(2) salt, carbon black, and polyvinylidene fluoride (PVDF) in a ratio of 80:10:10. The Ca(NO3)(2)-based electrode demonstrates an exceptionally long life cycling stability, and a reasonably sound specific capacitance of 234 F/g is obtained at a current density of 3 A/g. Via chemical and electrochemical reactions, the in-situ activation of the Ca(NO3)(2) forms an intermediate CaO which contributes to the pseudocapacitance of the electrode. The electrode undergoes a reversible redox reaction between Cu2+ <-> Cu+ during the charge-discharge process. Superior rate capability and excellent specific capacitance retention of similar to 120% over 2000 cycles are achieved compared with other inorganic salt electrodes. (C) 2017 Elsevier B.V. All rights reserved.</P>

Sensitivity of surface characteristics on the simulation of wind-blown-dust source in North America

Park, S.H.,Gong, S.L.,Gong, W.,Makar, P.A.,Moran, M.D.,Stroud, C.A.,Zhang, J. Pergamon Press ; Elsevier [distribution] 2009 Atmospheric environment Vol.43 No.19

Recently, a wind-blown-dust-emission module has been built based on a state-of-the-art wind erosion theory and evaluated in a regional air-quality model to simulate a North American dust storm episode in April 2001 (see Park, S.H., Gong, S.L., Zhao, T.L., Vet, R.J., Bouchet, V.S., Gong, W., Makar, P.A., Moran, M.D., Stroud, C., Zhang, J. 2007. Simulation of entrainment and transport of dust particles within North America in April 2001 (''Red Dust episode''). J. Geophys. Res. 112, D20209, doi:10.1029/2007JD008443). A satisfactorily detailed assessment of that module, however, was not possible because of a lack of information on some module inputs, especially soil moisture content. In this paper, the wind-blown-dust emission was evaluated for two additional dust storms using improved soil moisture inputs. The surface characteristics of the wind-blown-dust source areas in southwestern North America were also investigated, focusing on their implications for wind-blown-dust emissions. The improved soil moisture inputs enabled the sensitivity of other important surface characteristics, the soil grain size distribution and the land-cover, to dust emission to be investigated with more confidence. Simulations of the two 2003 dust storm episodes suggested that wind-blown-dust emissions from the desert areas in southwestern North America are dominated by emissions from dry playas covered with accumulated alluvial deposits whose particle size is much smaller than usual desert sands. As well, the source areas in the northwestern Texas region were indicated to be not desert but rather agricultural lands that were ''activated'' as a wind-blown-dust sources after harvest. This finding calls for revisions to the current wind-blown-dust-emission module, in which ''desert'' is designated to be the only land-cover category that can emit wind-blown dust.

Improvement of hydrogenated amorphous silicon germanium thin film solar cells by different p-type contact layer

Cho, J.,Pham, D.P.,Jung, J.,Shin, C.,Park, J.,Kim, S.,Tuan Le, A.H.,Park, H.,Iftiquar, S.M.,Yi, J. Pergamon 2016 Materials science in semiconductor processing Vol.41 No.-

In this study, we report an appreciably increased efficiency from 6% up to 9.1% of hydrogenated amorphous silicon germanium (a-SiGe:H) thin film solar cells by using a combination of different p-doped window layers, such as boron doped hydrogenated amorphous silicon (p-a-Si:H), amorphous silicon oxide (p-a-SiO<SUB>x</SUB>:H), microcrystalline silicon (p-@?c-Si:H), and microcrystalline silicon oxide (p-@?c-SiO<SUB>x</SUB>:H). Optoelectronic properties and the role of these p-layers in the enhancement of a-SiGe:H cell efficiency were also examined and discussed. An improvement of 1.62mA/cm<SUP>2</SUP> in the short-circuit current density (J<SUB>sc</SUB>) is attributed to the higher band gap of p-type silicon oxide layers. In addition, an increase in open-circuit voltage (V<SUB>oc</SUB>) by 150mV and fill factor (FF) by 6.93% is ascribed to significantly improved front TCO/p-layer interface contact.

간호대학생의 정보활용능력의 영향 요인에 대한 연구 : 셀프 리더십을 중심으로

최선엽,최가을,이현정,유명혜,안서현,박수현,하재영,홍신해,김한나,김지아 이화여자대학교 간호과학대학 2015 이화간호학회지 Vol.- No.49

Purpose: This study identifies the factors in nursing undergraduate curriculum related to improved information literacy, and the degree of relationship between information literacy and self-leadership among nursing undergraduate students. Method: Participants were 338 nursing undergraduates selected by convenience sampling at 19 Korean universities. Instruments were the self-leadership tool by Manz(1983), modified by Cho(2003) and the information literacy tool developed by Rhee(2008). The data were analyzed by t-test, ANOVA, and hierarchial multiple regression analysis with SPSS 22.0 Windows software. Results: Participants’ age(F=2.962, p<.001), grade(F=5.757, p=.001), experience in clinical nursing-practice(t=3.792, p<.001), GPA(F=3.373, p=.019) and experience in informatics education (t=3.291, p<.001) were statistically significant differences in the information literacy. Age(F=4.995, p=.007), Religion (t=3.593, p<.001), GPA (F=8.878, p<.001), satisfaction with the major subject (t=-4.399, p<.001) and the degree of information education necessity(t=1.993, p=.047) showed statistically significant differences in the self-leadership. Also there was a strong correlation between information literacy and self-leadership (Pearson’s r=.578, p<.001). Hierarchical-regression analysis revealed that the better self-leadership was associated with the higher information literacy(Adjusted R²=.355, R²=.382, p<.001). However, age, time using a computer, grade, religion, GPA, satisfaction with nursing as a major, and experience in informatics education were not significantly associated with information literacy. Conclusion: These findings implied the importance of educating information literacy which is a foundation for evidence-based-practice for nursing students. Considering the importance of self-leadership on information literacy, it is also essential to develop the current nursing undergraduate curriculum for maximizing the effectiveness of information literacy education reflecting the relationship between self-leadership and information literacy.

Differential growth of U and M type infectious haematopoietic necrosis virus in a rainbow trout–derived cell line, RTG-2

Park, J W,Moon, C H,Wargo, A R,Purcell, M K,Kurath, G Blackwell Publishing Ltd 2010 Journal of fish diseases Vol.33 No.7

<P>Abstract</P><P>Infectious haematopoietic necrosis virus (IHNV) is one of the most important viral pathogens of salmonids. In rainbow trout, IHNV isolates in the M genogroup are highly pathogenic, while U genogroup isolates are significantly less pathogenic. We show here that, at a multiplicity of infection (MOI) of 1, a representative U type strain yielded 42-fold less infectious virus than an M type strain in the rainbow trout–derived RTG-2 cell line at 24 h post-infection (p.i.). However, at an MOI of 10, there was only fivefold difference in the yield of infectious virus between the U and M strains. Quantification of extracellular viral genomic RNA suggested that the number of virus particles released from cells infected with the U strain at a MOI of 1 was 47-fold lower than from M-infected cells, but U and M virions were equally infectious by particle to infectivity ratios. At an MOI of 1, U strain intracellular viral genome accumulation and transcription were 37- and 12-fold lower, respectively, than those of the M strain at 24 h p.i. Viral nucleocapsid (N) protein accumulation in U strain infections was fivefold lower than in M strain infections. These results suggest that the block in U type strain growth in RTG-2 cells was because of the effects of reduced genome replication and transcription. The reduced growth of the U strain does not seem to be caused by defective genes, because the U and M strains grew equally well in the permissive <I>epithelioma papulosum cyprini</I> cell line at an MOI of 1. This suggests that host-specific factors in RTG-2 cells control the growth of the IHNV U and M strains differently, leading to growth restriction of the U type virus during the RNA synthesis step.</P>

p21-Activated kinase 4 promotes prostate cancer progression through CREB

Park, M-H,Lee, H-S,Lee, C-S,You, S T,Kim, D-J,Park, B-H,Kang, M J,Heo, W D,Shin, E-Y,Schwartz, M A,Kim, E-G Macmillan Publishers Limited 2013 Oncogene Vol.32 No.19

Prostate cancer is initially androgen-dependent but, over time, usually develops hormone- and chemo-resistance. The present study investigated a role for p21-activated kinase 4 (PAK4) in prostate cancer progression. PAK4 activation was markedly inhibited by H89, a specific protein kinase A (PKA) inhibitor, and PAK4 was activated by the elevation of cAMP. The catalytic subunit of PKA interacted with the regulatory domain of PAK4, and directly phosphorylated PAK4 at serine 474 (S474). Catalytically active PAK4 enhanced the transcriptional activity of CREB independent of S133 phosphorylation. Stable knockdown of PAK4 in PC-3 and DU145 prostate cancer cells inhibited tumor formation in nude mice. Decreased tumorigenicity correlated with decreased expression of CREB and its targets, including Bcl-2 and cyclin A1. Additionally, in androgen-dependent LNCap-FGC cells, PAK4 regulated cAMP-induced neuroendocrine differentiation, which is known to promote tumor progression. Finally, PAK4 enhanced survival and decreased apoptosis following chemotherapy. These results suggested that PAK4 regulates progression toward hormone- and chemo-resistance in prostate cancer, and this study identified both a novel activation mechanism and potential downstream effector pathways. Therefore, PAK4 may be a promising therapeutic target in prostate cancer.

Comparative study on photocatalytic performances of crystalline a- and b-Bi2O3 nanoparticles under visible light

Mohammed Jalalah,Adel A. Ismail,M. Faisal,Houcine Bouzid,Jea-Gun Park,S.A. Al-Sayari 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

a- and b-Bi2O3 nanoparticles were synthesized in the presence of either urea or polyethylene glycol. TheXRD, TEM, and Raman analysis indicated that a-(monoclinic) Bi2O3 nanoparticles were obtained usingeither sol–gel or hydrothermal method in the presence of urea; however b-(tetragonal) phase of Bi2O3was formed using hydrothermal method in the presence of polyethylene glycol. The b-Bi2O3nanoparticles exhibited higher photocatalytic activity than a-Bi2O3. MB was completely photodegradedafter 6 h of visible light illumination using b-Bi2O3 photocatalyst whereas only 30% was photodegradedusing a-Bi2O3. The photodegradation rate of b-Bi2O3 was 5.7 times greater than that a-Bi2O3nanoparticles.