Uncovering stakeholders in public–private relations on social media: a case study of the 2015 Volkswagen scandal

Jung, K.,Chilton, K.,Valero, J. N. Springer Science + Business Media 2017 Quality & quantity Vol.51 No.3

<P>While researchers have focused on the nature of interpersonal communication on social media, few have investigated the patterns and structures of interactions among stakeholders engaged in an unexpected event. On September 18, 2015, the United States Environmental Protection Agency issued a notice of violation of the U.S. Clean Air Act to Volkswagen Group of America, Inc., citing Volkswagen's inappropriate software that circumvented the United States' emission standards. This research is systemically designed to examine the evolutionary structures of interpersonal issue networks on social media by focusing on the 2015 Volkswagen scandal on social media. The interpersonal network emerged and evolved to build a discourse on issues by stakeholders after the event. By using longitudinal data collected from the Volkswagen USA's Facebook page between September 17 and 20, 2015, this research tests four hypothesized network structures, which are reciprocity, transitivity, popularity, and activity, which assess the evolution of interpersonal issue networks. The results of exponential random graph models, analyzing 4131 stakeholders, show that interpersonal issue networks on social media have evolved overtime into a set of reciprocal relations and stakeholders transmitting critical information to bystanders. The findings imply that stakeholders who have Volkswagen's cars and stocks play a critical role in placating the scandal by mutually interacting with diverse bystanders on social media.</P>

Amelioration of Horticultural Growing Media Properties Through Rice Hull Biochar Incorporation

Kim, H. S.,Kim, K. R.,Yang, J. E.,Ok, Y. S.,Kim, W. I.,Kunhikrishnan, A.,Kim, K. H. Springer Science + Business Media 2017 Waste and biomass valorization Vol.8 No.2

<P>The current study was conducted in order to examine the applicability of rice hull derived biochar (BC) to improve the properties of growing media (GM). Biochar was incorporated into a growing media composed of coir dust, perlite and vermiculite at 0, 1, 2 and 5 % (w/w). Subsequently, the physicochemical properties of the GM-BC mixtures were determined in the cultivation of kale (Brassica oleracea L. var. acephala) for 25 days through the observation of the plant growth response. During kale cultivation in the GM-BC mixtures, the leachates were collected and analyzed to determine the changes in nutrient levels due to BC amendment. Application of rice hull-derived BC increased the retention of nutrients in the growing media due to a biochar-induced increase in cation exchange capacity, in addition to the biochar nutrient supply such as potassium and phosphorus. Furthermore, a higher water content of the growing media was observed when BC was used as an amendment, mainly due to the increased proportion of pore space available for water storage. The growth rate of kale was also increased as the biochar incorporation rate was increased. For example, the dry weight of the kale shoots was 150 % higher when grown in media containing 5 % GM-BC mixture than with the control growing media (with no biochar). From these results, it can be concluded that the rice hull-derived biochar would be a practically applicable amendment to improve the properties of the growing media.</P>

Topic category analysis on twitter via cross-media strategy

Springer Science + Business Media 2016 MULTIMEDIA TOOLS AND APPLICATIONS Vol.75 No.20

<P>The growing popularity of social media provides a huge volume of social data including Tweets. These collections of social data can be potentially useful, but the extent of meaningful data in these collections has not been sufficiently researched, especially in South Korea Twitter data. In general, the South Korea Twitter data has been researched as a source of political media. Nonetheless, previous research on South Korea Twitter data has not adequately covered what kind of trend Twitter represents in terms of major topic categories such as politics, economics, or sports. In this paper, we present a cross-media approach to define the nature of South Korea Tweets by inferring the topic category distribution through short-text categorization. We select newspapers as cross-media, examine the categorization of news articles from major newspapers, and then train our classifier based on the features from each topic category. In addition, for grafting news topics onto South Korea Tweets, we propose a word clustering and filtering approach to exclude those words that do not provide semantic content for the topic categories. Based on the proposed procedures, we analyze the South Korea Tweets to determine the primary topic category focus of Twitter users. We observe the special behaviors of the South Korea Twitter users based on various parameters such as date, time slot, and day of the week. Because our research includes a macroscopic analysis of Twitter data using a cross-media strategy, our research can provide useful resources for other social media analysis as well.</P>

Beacon-based active media control interface in indoor ubiquitous computing environment

Springer Science + Business Media 2016 CLUSTER COMPUTING Vol.19 No.1

<P>In ubiquitous computing, diverse media technologies have recently been extensively researched and applied to various fields. The goal of media technologies is to improve our daily lives by enabling us to control activemedia devices such as smart phones, tablets, and TVs. The locations of users are important to providing a variety of services to users. In addition, given that all devices cannot be simultaneously utilized, and only one device is sometimes being used, the location information can be utilized to help determine one of the core active media devices at a specific instant in time. This paper proposes an active media-control interface that is based on location recognition methods using beacons in indoor ubiquitous computing. In the proposed environment, users have a beacon that denotes the location of each user. The one that is the nearest from the beacon is selected from among multiple active media devices for servicing. In the experiments, four access points and one beacon was used to validate the proposed method. The advantage of the proposed method is that it enables us to apply active media technology to indoor environments. By recognizing user locations in indoor environments, several kinds of active media services become available.</P>

Effect of a microwave warming of cell culture media on cell viability and confluence rate

Yoon, J. K.,Sim, W. Y.,Xu, F.,Lee, W. G. Springer Science + Business Media 2016 Microsystem Technologies Vol.22 No.9

<P>Here we present a method for rapidly and stably warming up a small volume of cell culture media that can maintain cell viability and confluence rate. This method uses microwave radiation for warming without any direct contact with water, preventing the potential issue of contamination induced by the use of a water bath. To demonstrate the proof of concept validation, we used a conventional microwave oven for warming cell culture media. In our experiments, it took only 10 s to warm a 50 mL-media tube (mostly proper volume for the use of microfluidic cell culture experiments) up to 37 degrees C. Multiple tubes can also be used to increase the volume of cell culture media by placing them in a plastic support within the oven at the same time in a scalable manner. The results show that there was no jump discontinuity to a higher temperature than 37 degrees C within 10 s. Both apoptosis and necrosis were monitored and examined to confirm whether the new method can affect cell viability and metabolism. The proposed method is fast, easy and user-friendly in conventional cell culture process, even scalable for the use of large media volume, and free of biological contamination due to water contact occurred by use of conventional water baths. We urthermore believe that this approach can be potentially helpful for advancing on-chip cell culture process that may require a small volume of cell culture media often used in microfluidic devices.</P>

Studies of hypro-mellose (HPMC) functionalized ZnS:Mn fluorescent quantum dots

Jain, A.,Jain, A.,Panwar, S.,Singh, R.,Singhal, M.,Sharma, J. K.,Ahuja, R.,Jeon, H. C.,Kang, T. W.,Kumar, S. Springer Science + Business Media 2017 Journal of materials science. Materials in electro Vol.28 No.2

<P>Fluorescent ZnS:Mn quantum dots coated with hypro-mellose (HPMC) were synthesized by using simple and facile chemical precipitation technique in which HPMC acts as a novel organic surfactant to passivate the surface, to tune the optical properties and also to functionalize the surface of quantum dot for a futuristic controlled drug release applications. Morphological and optical characterizations were done to see the effect of HPMC coating on ZnS: Mn quantum dots. Structural and morphological studies was done by using XRD and TEM respectively. XRD studies confirms the pure zinc blende phase for all the samples. TEM studies shows that HPMC is efficiently doing the surface passivation in doped quantum dots. Optical studies were done by using UV-visible, FTIR and time resolved photoluminescence. UV-visible studies shows that quantum confinement effect is more prominent and also tunable in case of HPMC coated manganese doped ZnS quantum dots. FTIR studies confirms the functionalization of HPMC on the surface of doped ZnS quantum dots. Laser induced time resolved photoluminescence studies were also done to see the effect of HPMC on the photoluminescence intensity of doped quantum dots. Time resolved studies clearly shows the much desired luminescence stability of the HPMC coated quantum dots. It is observed that both the structural and optical characteristics have strong dependence on capping concentration. As HPMC is a very important viscoelastic polymer and organic surfactant used in various types of drug formulations, these studies opens a new way in the area of efficient drug delivery, controlled drug release and targeting.</P>

Strategies for Hot Electron-Mediated Catalytic Reactions: Catalytronics

Park, J. Y.,Lee, S. W.,Lee, C.,Lee, H. Springer Science + Business Media 2017 Catalysis letters Vol.147 No.8

<P>A pulse of high kinetic energy electrons can be generated after deposition of external energy to a metallic surface, such as the absorption of light or exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the phonons of the metal atoms and are called 'hot electrons'. The detection of hot electrons on the surface of a catalyst is an active subject in the field of surface science. More significantly, it has been found that surface processes, including desorption, diffusion, and chemical rearrangement of atomic and molecular species, are driven by the flow of hot electrons on the surface. The strong correlation between hot electron generation and surface phenomena suggests that hot electrons can be used to control surface chemical reactions, which is known as hot electron chemistry. In this Perspective, research strategies for electronic control of catalytic reactions by engineering metal-oxide interfaces and manipulating hot electron flux are discussed. Catalytic nanodiodes consisting of a metal catalyst film, semiconductor layers, and Ohmic contact pads have revealed a strong correlation between the hot electron flux (chemicurrent) and catalytic activity under CO oxidation and hydrogen oxidation. We highlight recent results on new architecture for hot electron collection, including a Au/TiO2 nanodiode and a graphene/TiO2 nanodiode, that show that hot electrons can be used for quantitative measurement of catalytic activity. We show that the direct conversion of photon energy to hot electron flows can be achieved in metal-semiconductor nanodiodes. Hot electrons and surface plasmons can be used to change the catalytic activity using metal-oxide nanocatalysts. This strategy requires an understanding of both the electronic and chemical properties of metal-oxide interfaces, as well as the combined measurement of electronic and chemical signals on nanoscale electronic devices during catalytic reactions, and therefore can be referred to as 'catalytronics', which is the combination of catalysis and electronics.</P>

Synthesis of hollow carbon-W18O49 composite and its photocatalytic properties

Park, J. e.,Vo, V.,Hoan, N. T.,Hoang, L. H.,Kim, S. J. Springer Science + Business Media 2016 Journal of materials science. Materials in electro Vol.27 No.3

<P>Composites of carbon and W18O49 were successfully synthesized by heating the mixtures of WO3 and urea at a temperature between 600 and 800 degrees C in inert atmosphere. The obtained materials were characterized by XRD, SEM, TEM, Raman, XPS, TG-DTA and N-2 adsorption/desorption at 77 K. The results showed that the composites consisted of W18O49 as a main phase which was coated by a thin carbon layer and exhibited a change in shape with heating temperature. The hollow form appeared from the treatment temperature of 700 degrees C and remained till 900 degrees C. However, at treatment 900 degrees C, the W18O49 disappeared and WO2 formed instead. The adsorption and visible-light photocatalytic degradation of methylene blue on the composites were evaluated.</P>

Odontoblastic inductive potential of epithelial cells derived from human deciduous dental pulp

Lee, H. K.,Park, J. W.,Seo, Y. M.,Kim, H. H.,Lee, G.,Bae, H. S.,Park, J. C. Springer Science + Business Media 2016 Journal of molecular histology Vol.47 No.3

<P>For the dentin regeneration, dental epithelial cells are indispensible and must possess odontoblastic induction capability. Epithelial cell-like stem cells were recently identified in human deciduous dental pulp (DPESCs). However, their cellular characteristics remain poorly defined. The purpose of this study was to characterize DPESCs compared to HAT-7 ameloblastic cells. Expression levels of ameloblast-specific markers [odontogenic ameloblast-associated protein (Odam), matrix metalloproteinase (Mmp)-20, amelogenin, and ameloblastin] were detected in DPESCs. Co-culturing odontoblastic MDPC-23 cells with DPESCs increased expression of odontoblast differentiation markers (Dmp1 and Dspp) from days 4 to 10, while the expression of bone sialoprotein rapidly decreased. MDPC-23 cells cultured in DPESC-conditioned medium (CM) showed increased Dspp promoter activity compared with control MDPC-23 cultures. Mineralization was first observed in the CM groups from day 4 and proceeded rapidly until day 14, whereas mineralized nodules were found from day 7 in control media-cultured cells. In conclusion, DPESCs in human deciduous pulp possess ameloblast-like characteristics and differentiation properties, and substances derived from DPESCs promote odontoblastic differentiation. Thus, our results indicate that DPESCs can be a realistic epithelial source for use in odontoblastic induction and dentin formation of dental mesenchymal cells.</P>

Improved drop reliability of Sn–Ag–Cu solder joints by Zn addition to a Cu wetting layer

Park, J. Y.,Kim, Y. M.,Kim, Y. H. Springer Science + Business Media 2015 Journal of materials science. Materials in electro Vol.26 No.8

<P>Cu-20 wt% Zn solder wetting layers were fabricated by electroplating in cyanide and non-cyanide solutions, and board-level drop impact reliability was evaluated for Sn-Ag-Cu (SAC) solder joints formed on Cu-Zn layers. Adding Zn to the Cu wetting layer suppressed the formation of a large Ag3Sn plate in the solder and delayed interfacial intermetallic compound (IMC) growth in the solder/Cu-Zn interfaces. Formation of Cu3Sn IMC and microvoids was not observed in the Cu6Sn5/CuZn interface during thermal aging. The drop impact reliability of the Cu-Zn/SAC/Cu-Zn solder joints was superior to that of Cu/SAC/Cu solder joints, both before and after aging. The drop impact performance of the Cu-Zn specimens was similar whether their Cu-Zn layers were electroplated in cyanide or non-cyanide solution. Drop impact reliability of both Cu and Cu-Zn specimens decreased after aging due to IMC growth and/or microvoid formation in the solder interfaces. Interfacial microstructure influenced the failure mode of the solder joints. For Cu specimens, the dominant failure sites were a Cu6Sn5/Cu interface before aging and a Cu3Sn/Cu interface after aging. The formation of a large Ag3Sn plate facilitated crack growth. For Cu-Zn specimens, the crack always propagated inside the Cu6Sn5 layer. Microstructural changes in the solder interfaces arising from the addition of Zn contributed to the improvement of drop impact reliability of SAC solder joints.</P>