Influence of polar solvents on photovoltaic performance of Monascus red dye-sensitized solar cell

Lee, J. W.,Kim, T. Y.,Ko, H. S.,Han, S.,Lee, S. H.,Park, K. H. Elsevier Science B.V., Amsterdam. 2014 Spectrochimica acta. Part A, Molecular and biomole Vol.126 No.-

Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from Monascus red pigment as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in Monascus red DSSC using different solvents. The effect of polar aprotic and protic solvents including water, ethanol, and dimethylsulfoxide (DMSO) used in the sensitization process was investigated for the improvement in conversion efficiency of a cell. As for the Monascus red dye-sensitized electrode in DMSO solvent, the solar cell yields a short-circuit current density (J(sc)) of 1.23 mA/cm(2), a photovoltage (V-oc) of 0.75 V. and a fill factor of 0.72, corresponding to an energy conversion efficiency (eta) of 0.66%. (C) 2014 Elsevier B.V. All rights reserved.

NF-κB signaling is key in the wound healing processes of silk fibroin

Park, Ye Ri,Sultan, Md. Tipu,Park, Hyun Jung,Lee, Jung Min,Ju, Hyung Woo,Lee, Ok Joo,Lee, Dong Jin,Kaplan, David L.,Park, Chan Hum Elsevier Science B.V. Amsterdam 2018 ACTA BIOMATERIALIA Vol. No.

<P><B>Abstract</B></P> <P>Silk fibroin (SF) is a well-studied biomaterial for tissue engineering applications including wound healing. However, the signaling mechanisms underlying the impact of SF on this phenomenon have not been determined. In this study, through microarray analysis, regulatory genes of NF-ĸB signaling were activated in SF-treated NIH3T3 cells along with other genes. Immunoblot analysis confirmed the activation of the NF-ĸB signaling pathway as SF induced protein expression levels of IKKα, IKKβ, p65, and the degradation of IκBα. The treatment of NIH3T3 cells with SF also increased the expression of cyclin D1, vimentin, fibronectin, and vascular endothelial growth factor (VEGF). The expression of these factors by SF treatment was abrogated when NF-ĸB was inhibited by a pharmacological inhibitor Bay 11-7082. Knockdown of NF-ĸB using siRNA of IKKα and IKKβ also inhibited the SF-induced wound healing response of the NIH3T3 cells in a wound scratch assay. Collectively, these results indicated that SF-induced wound healing through the canonical NF-κB signaling pathway via regulation of the expression of cyclin D1, vimentin, fibronectin, and VEGF by NIH3T3 cells. Using an <I>in vivo</I> study with a partial-thickness excision wound in rats we demonstrated that SF-induced wound healing via NF-κB regulated proteins including cyclin D1, fibronectin, and VEGF. The <I>in vitro</I> and <I>in vivo</I> data suggested that SF induced wound healing via modulation of NF-ĸB signaling regulated proteins.</P> <P><B>Statement of Significance</B></P> <P>Silk fibroin has been effectively used as a dressing for wound treatment for more than a century. However, mechanistic insight into the basis for wound healing via silk fibroin has not been elucidated. Here we report a key mechanism involved in silk fibroin induced wound healing both <I>in vitro</I> and <I>in vivo.</I> Using genetic- and protein-level analyses, NF-κB signaling was found to regulate silk fibroin-induced wound healing by modulating target proteins. Thus, the NF-κB signaling pathway may be utilized as a therapeutic target during the formulation of silk fibroin-based biomaterials for wound healing and tissue engineering.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Threading dislocation reduction in epitaxial GaN using V-groove patterned sapphire substrate with embedded silica nanospheres

Han, N.,Park, Y. J.,Han, M.,Ryu, B. D.,Ko, K. B.,Chandramohan, S.,Choi, C. J.,Cuong, T. V.,Hong, C. H. Elsevier Science B.V., Amsterdam. 2014 Materials letters Vol.123 No.-

dramatic reduction in threading dislocation density and stress-relaxation was simultaneously achieved in GaN epilayer using a silica nanosphere embedded structure on V-groove patterned sapphire substrate by metal-organic chemical vapor deposition. By depositing silica nanospheres at two different instances during a growth process, a two-step growth that included selective area growth and lateral overgrowth was initiated. This approach led to GaN template of high crystal quality, which was confirmed from x-ray diffraction rocking curve and micro-Raman measurements and further corroborated by transmission electron microscopy. GaN light-emitting diode fabricated by this strategy showed a significant enhancement in the light output power. (C) 2014 Elsevier B.V. All rights reserved.

Simultaneous determination of nine bioactive compounds in Yijin-tang via high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry

Yang, Hye Jin,Yim, Nam-Hui,Lee, Kwang Jin,Gu, Min Jung,Lee, Bohyoung,Hwang, Youn-Hwan,Ma, Jin Yeul Elsevier Science B.V., Amsterdam 2016 Integrative medicine research Vol.7 No.4

<P><B>Background</B></P><P>Yijin-tang (YJ) has been used traditionally for the treatment of cardiovascular conditions, nausea, vomiting, gastroduodenal ulcers, and chronic gastritis. In this study, a simple and sensitive high-performance liquid chromatography (HPLC) method was developed for the quantitation of nine bioactive compounds in YJ: homogentisic acid, liquiritin, naringin, hesperidin, neohesperidin, liquiritigenin, glycyrrhizin, 6-gingerol, and pachymic acid.</P><P><B>Methods</B></P><P>Chromatographic separation of the analytes was achieved on an RS Tech C<SUB>18</SUB> column (4.6 mm × 250 mm, 5 μm) using a mobile phase composed of water containing 0.1% (v/v) trifluoroacetic acid (TFA) and acetonitrile with a gradient elution at a flow rate of 1.0 mL/min.</P><P><B>Results</B></P><P>Calibration curves for all analytes showed good linearity (R<SUP>2</SUP> ≥ 0.9995). Lower limits of detection and lower limits of quantification were in the ranges of 0.03–0.17 μg/mL and 0.09–0.43 μg/mL, respectively. Relative standard deviations (RSDs; %) for intra- and interday assays were < 3%. The recovery of components ranged from 98.09% to 103.78%, with RSDs (%) values ranging from 0.10% to 2.59%.</P><P><B>Conclusion</B></P><P>This validated HPLC method was applied to qualitative and quantitative analyses of nine bioactive compounds in YJ and fermented YJ, and may be a useful tool for the quality control of YJ.</P>

Boronic acid-tethered amphiphilic hyaluronic acid derivative-based nanoassemblies for tumor targeting and penetration

Jeong, Jae Young,Hong, Eun-Hye,Lee, Song Yi,Lee, Jae-Young,Song, Jae-Hyoung,Ko, Seung-Hak,Shim, Jae-Seong,Choe, Sunghwa,Kim, Dae-Duk,Ko, Hyun-Jeong,Cho, Hyun-Jong Elsevier Science B.V. Amsterdam 2017 ACTA BIOMATERIALIA Vol. No.

<P><B>Abstract</B></P> <P>(3-Aminomethylphenyl)boronic acid (AMPB)-installed hyaluronic acid–ceramide (HACE)-based nanoparticles (NPs), including manassantin B (MB), were fabricated for tumor-targeted delivery. The amine group of AMPB was conjugated to the carboxylic acid group of hyaluronic acid (HA) <I>via</I> amide bond formation, and synthesis was confirmed by spectroscopic methods. HACE-AMPB/MB NPs with a 239-nm mean diameter, narrow size distribution, negative zeta potential, and >90% drug encapsulation efficiency were fabricated. Exposed AMPB in the outer surface of HACE-AMPB NPs (in the aqueous environment) may react with sialic acid of cancer cells. The improved cellular accumulation efficiency, <I>in vitro</I> antitumor efficacy, and tumor penetration efficiency of HACE-AMPB/MB NPs, compared with HACE/MB NPs, in MDA-MB-231 cells (CD44 receptor-positive human breast adenocarcinoma cells) may be based on the CD44 receptor-mediated endocytosis and phenylboronic acid-sialic acid interaction. Enhanced <I>in vivo</I> tumor targetability, infiltration efficiency, and antitumor efficacies of HACE-AMPB NPs, compared with HACE NPs, were observed in a MDA-MB-231 tumor-xenografted mouse model. In addition to passive tumor targeting (based on an enhanced permeability and retention effect) and active tumor targeting (interaction between HA and CD44 receptor), the phenylboronic acid-sialic acid interaction can play important roles in augmented tumor targeting and penetration of HACE-AMPB NPs.</P> <P><B>Statement of Significance</B></P> <P>(3-Aminomethylphenyl)boronic acid (AMPB)-tethered hyaluronic acid-ceramide (HACE)-based nanoparticles (NPs), including manassantin B (MB), were fabricated and their tumor targeting and penetration efficiencies were assessed in MDA-MB-231 (CD44 receptor-positive human adenocarcinoma) tumor models. MB, which exhibited antitumor efficacies <I>via</I> the inhibition of angiogenesis and hypoxia inducible factor (HIF)-1, was entrapped in HACE-AMPB NPs in this study. Phenylboronic acid located in the outer surface of HACE-AMPB/MB NPs (in the aqueous <I>milieu</I>) may react with the sialic acid over-expressed in cancer cells and intramolecular B‒O bond can be formed. This phenylboronic acid-sialic acid interaction may provide additional tumor targeting and penetration potentials together with an enhanced permeability and retention (EPR) effect (passive tumor targeting) and HA-CD44 receptor interaction (active tumor targeting). Developed HACE-AMPB NP may be one of promising nanocarriers for the imaging and therapy of CD44 receptor-expressed cancers.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Increase of glucocorticoids is not required for the acquisition, but hinders the extinction, of lithium-induced conditioned taste aversion

Kim, K. N.,Kim, B. T.,Kim, Y. S.,Lee, J. H.,Jahng, J. W. Elsevier Science B.V., Amsterdam. 2014 european journal of pharmacology Vol.730 No.-

Lithium chloride at doses sufficient to induce conditioned taste aversion (CTA) causes c-Fos expression in the paraventricular nucleus and increases the plasma level of corticosterone with activation of the hypothalamic-pituitary-adrenal axis. This study was conducted to define the role of glucocorticoid in the acquisition and extinction of lithium-induced CTA. In experiment 1, Sprague-Dawley rats received dexamethasone (2 mg/kg) or RU486 (20 mg/kg) immediately after 5% sucrose access, and then an intraperitoneal injection of isotonic lithium chloride (12 ml/kg) was followed with 30 min interval. Rats had either 1 or 7 days of recovery period before the daily sucrose drinking tests. In experiment 2, rats were conditioned with the sucrose-lithium pairing, and then received dexamethasone or vehicle at 30 min before each drinking test. In experiment 3, adrenalectomized (ADX or ADX+B) rats were subjected to sucrose drinking tests after the sucrose-lithium pairing. Dexamethasone, but not RU486, pretreatment blunted the formation of lithium-induced CTA memory. Dexamethasone prior to each drinking test suppressed sucrose consumption and prolonged the extinction of lithium-induced CTA. Sucrose consumption was significantly suppressed not only in ADX+B rats but also in ADX rats during the first drinking session; however, a significant decrease was found only in ADX rats on the fourth drinking session. These results reveal that glucocorticoid is not a necessary component in the acquisition, but an important player in the extinction, of lithium induced CTA, and suggest that a pulse increase of glucocorticoid may hinder the extinction memory formation of lithium induced CTA. (C) 2014 Elsevier B.V.. All rights reserved.

Extensions of smooth mappings into biduals and weak continuity

Choi, Y.S.,Hajek, P.,Lee, H.J. Academic Press ; Elsevier Science B.V. Amsterdam 2013 Advances in mathematics Vol.234 No.-

We study properties of uniformly differentiable mappings between real Banach spaces. Among our main results are generalizations of a number of classical results for linear operators on L<SUB>~</SUB>-spaces into the setting of uniformly differentiable mappings. Denote by B<SUB>X</SUB> the closed unit ball of a Banach space X. Let X be a L<SUB>~,λ</SUB>-space, λ≥1, and let Y be a Banach space. Let T:B<SUB>X</SUB>→Y be a continuous mapping which is uniformly differentiable in the open unit ball of X. Assuming that T is weakly compact, then T can be extended, preserving its best smoothness properties, into the mapping from the 1λ-multiple of the unit ball of any superspace of the domain space X into the same range space Y. We also show that T maps weakly Cauchy sequences from λB<SUB>X</SUB> into norm convergent sequences in Y. This is a uniformly smooth version of the Dunford-Pettis property for the L<SUB>~,λ</SUB>-spaces. We also show that a uniformly differentiable mapping T, which is not necessarily weakly compact, still maps weakly Cauchy sequences from λB<SUB>X</SUB> into norm convergent sequences in Y, provided Y<SUP>**</SUP> does not contain an isomorphic copy of c<SUB>0</SUB>. We prove that for certain pairs of Banach spaces the completion of the space of polynomials equipped with the topology of uniform convergence on the bounded sets (of the functions and their derivatives up to order k) coincides with the space of uniformly differentiable (up to order k) mappings. Our work is based on a number of tools that are of independent interest. We prove, for every pair of Banach spaces X,Y, that any continuous mapping T:B<SUB>X</SUB>→Y, which is uniformly differentiable of order up to k in the interior of B<SUB>X</SUB>, can be extended, preserving its best smoothness, into a bidual mapping T@?:B<SUB>X^*^*</SUB>→Y<SUP>**</SUP>. Another main tool is a result of Zippin's type. We show that weakly Cauchy sequences in X=C(K) can be uniformly well approximated by weakly Cauchy sequences from a certain C[0,α], α is a countable ordinal, subspace of X<SUP>**</SUP>.

The inductive effect of ginsenoside F2 on hair growth by altering the WNT signal pathway in telogen mouse skin

Shin, H. S.,Park, S. Y.,Hwang, E. S.,Lee, D. G.,Song, H. G.,Mavlonov, G. T.,Yi, T. H. Elsevier Science B.V., Amsterdam. 2014 european journal of pharmacology Vol.730 No.-

This study was conducted to confirm the possibility of using minor ginseng saponin F2 by oral administration on hair anagen induction effects. The signaling pathway and anagen induction effect of ginsenoside F2 were investigated and compared with finasteride on the effect of hair growth induction. The cell-based MTT assay results indicated that the proliferation rates of HHDPC and HaCaT treated with F2 significantly increased by 30% compared with the finasteride-treated group. A western blot study showed that the expression of beta-catenin Lef-1 and DKK-1 increased by 140, 200% and decreased by 40% in the F2 treated group, respectively compared to that of finasteride-treated group. C57BL/6 mice were subjected to the same treatments. The hair growth promotion rates were compared with groups treated with finasteride, which was 20% higher in the F2 treated group. Tissue histological analysis results showed the number of hair follicles, thickness of the epidermis, and follicles of the anagen phase which increased in the F2 treated group, compared with the finasteride-treated groups. Moreover, the effect of F2 on hair growth was confirmed through the immunofluorescence (IF) methods indicating the expression aspect of Wnt signal pathway related factors in the tissue of C57BL/6 mouse. Our results considered the expression increase in beta-calenin, Lef-1 which was suggested as a major factor related to the development and growth of hair follicle and the decrease in DKK-1 when entering catagen by F2. As the data showed. F2 might be a potential new therapeutic source for anagen induction and hair growth through the Wnt signal pathway. (C) 2014 Elsevier B.V. All rights reserved.

A comprehensive index for stream depletion in coupled human-water systems

Choi, S.,Lee, S.O.,Park, J. ELSEVIER SCIENCE B.V; AMSTERDAM 2017 JOURNAL OF HYDROENVIRONMENT RESEARCH Vol.16 No.-

<P>Intensive land use and land cover (LULC) change along with the gradually increasing effects of climate change have made streams both hydrologically and ecologically vulnerable to depletion. Since stream depletion has a direct impact on human and ecological water use with socioeconomic and ecological consequences, it is imperative to manage streams to keep them in a healthy state. In this study, we developed a stream depletion potential index (SDPI) based on the concept of a coupled human-water system (CHWS) operating at simultaneous, interacting scales, and we tested its applicability to watersheds across South Korea. Eight indicators -precipitation, dry days, effective basin area, stream water usage, return flow, groundwater usage, impervious area, and environmental flow supplied by dams -were identified as the key variables for the SDPI. We adopted the Structural Equation Model (SEM) to estimate the weights of the identified indicators based on their causal relationships. Furthermore, we applied three different weighting schemes for urban, rural, and intermediate areas to make the index more effective and applicable to watershed LULC. The spatial distribution of the SDPI results indicated that the western Han River, the central and southern Nak-Dong River and some parts of the southwestern region of the Korean peninsula are prone to stream depletion from several different causes. The SDPI, by predicting changing streamfiow characteristics, can be used by policy makers and stakeholders to determine a safe yield for both human and environmental stream use without causing a long-term decline of water availability. (C) 2017 International Association for Hydro-environment Engineering and Research, Asia Pacific Division. Published by Elsevier B.V. All rights reserved.</P>

Classification of structured validation data using stateless and stateful features

Schwenk, G.,Pabst, R.,Mü,ller, K.R. Elsevier Science B.V., Amsterdam. 2019 COMPUTER COMMUNICATIONS -GUILDFORD THEN AMSTERDAM- Vol.138 No.-

<P><B>Abstract</B></P> <P>To reliably identify problems impacting the service quality and system dependability of mobile communication networks, the monitored data needs to be validated. This paper proposes and evaluates analysis methods, features and learning methods for the automatic validation of such data, with a special focus on failure data of mobile communication data. This data can be analyzed for discriminating failures caused by problems in the infrastructure (valid failures) from those caused by other circumstances like device imperfections (invalid failures), with the purpose of filtering the invalid failures, which effectively increases both dependability and value of the underlying data. To represent the complex structural and temporal properties of the mobile communication data, two complementary feature representations are proposed and compared, followed by a discussion of classification methods which are suitable for these feature spaces and for an interpretation of their results to support manual auditing. Their classification performances on these feature spaces are evaluated and compared to competitive approaches. In the evaluation a classification performances of up to 97% AUC–ROC is achieved. This renders our approach a good alternative to using manual matching rules, which require costly expert-knowledge and are much more time-consuming to define and maintain — while also highlighting the relevance of combining feature spaces of different problem perspectives. Additionally it is shown that using non-proprietary data analysis can enable feature representations nearly as expressive as those created by using proprietary analysis methods, which allows a broader application of the proposed methods, due to the lower processing requirements.</P>