bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concise Review: Carbon Nanotechnology: Perspectives in Stem Cell Research
Authors: Pryzhkova Marina V. 
Published: April 2013

Abstract
Carbon nanotechnology has developed rapidly during the last decade, and carbon allotropes, especially graphene and carbon nanotubes, have already found a wide variety of applications in industry, high-tech fields, biomedicine, and basic science. Electroconductive nanomaterials have attracted great attention from tissue engineers in the design of remotely controlled cell-substrate interfaces. Carbon nanoconstructs are also under extensive investigation by clinical scientists as potential agents in anticancer therapies. Despite the recent progress in human pluripotent stem cell research, only a few attempts to use carbon nanotechnology in the stem cell field have been reported. However, acquired experience with and knowledge of carbon nanomaterials may be efficiently used in the development of future personalized medicine and in tissue engineering.
Highly Efficient and Bendable Organic Solar Cells with Solution‐Processed Silver Nanowire Electrodes
Authors: Song Myungkwan , You Dae Sung , Lim Kyounga , Park Sujin , Jung Sunghoon , Kim Chang Su , Kim Dong‐Ho , Kim Do‐Geun , Kim Jongk‐Kuk , Park Juyun , Kang Yong‐Cheol , Heo Jinhee , Jin Sung‐Ho , Park Jong Hyun , Kang Jae‐Wook 
Published: April 2013

AbstractHighly efficient and bendable organic solar cells (OSCs) are fabricated using solution‐processed silver nanowire (Ag NW) electrodes. The Ag NW films were highly transparent (diffusive transmittance ≈ 95% at a wavelength of 550 nm), highly conductive (sheet resistance ≈ 10 Ω sq−1), and highly flexible (change in resistance ≈ 1.1 ± 1% at a bending radius of ≈200 μm). Power conversion efficiencies of ≈5.80 and 5.02% were obtained for devices fabricated on Ag NWs/glass and Ag NWs/poly(ethylene terephthalate) (PET), respectively. Moreover, the bendable devices fabricated using the Ag NWs/PET films decrease slightly in their efficiency (to ≈96% of the initial value) even after the devices had been bent 1000 times with a radius of ≈1.5 mm.
Catalytic Saloplastics: Alkaline Phosphatase Immobilized and Stabilized in Compacted Polyelectrolyte Complexes
Authors: Tirado Patricia , Reisch Andreas , Roger Emilie , Boulmedais Fouzia , Jierry Loïc , Lavalle Philippe , Voegel Jean‐Claude , Schaaf Pierre , Schlenoff Joseph B. , Frisch Benoît 
Published: April 2013

AbstractNovel biochemically active compact polyelectrolyte complexes (CoPECs) are obtained through a simple coprecipitation and compaction procedure. As shown for the system composed of poly(acrylic acid) (PAA) and poly(allylamine) (PAH) as polyelectrolytes and alkaline phosphatase (ALP) as enzyme, the enzyme can be firmly immobilized into these materials. The ALP not only remains active in these materials, but the matrix also enhances the specific activity of the enzyme while protecting it from deactivation at higher temperature. The presence of the matrix allows fine control and substantial enhancement of reaction rates by varying the salt concentration of the contacting solution or temperature. The excellent reusability, together with the ease of co‐immobilizing other useful components, such as magnetic particles, allowing facile handling of the CoPECs, makes these materials interesting candidates for variable scaffolds for the immobilization of enzymes for small‐ and large‐scale enzyme‐catalyzed processes.
Strontium Diffusion in Magnetron Sputtered Gadolinia‐Doped Ceria Thin Film Barrier Coatings for Solid Oxide Fuel Cells
Authors: Sønderby Steffen , Popa Petru Lunca , Lu Jun , Christensen Bjarke Holl , Almtoft Klaus Pagh , Nielsen Lars Pleth , Eklund Per 
Published: April 2013

AbstractStrontium (Sr) diffusion in magnetron sputtered gadolinia‐doped ceria (CGO) thin films is investigated. For this purpose, a model system consisting of a screen printed (La,Sr)(Co,Fe)O3−δ (LSCF) layer, and thin films of CGO and yttria‐stabilized zirconia (YSZ) is prepared to simulate a solid oxide fuel cell. This setup allows observation of Sr diffusion by observing SrZrO3 formation using X‐ray diffraction while annealing. Subsequent electron microscopy confirms the results. This approach presents a simple method for assessing the quality of CGO barriers without the need for a complete fuel cell test setup. CGO films with thicknesses ranging from 250 nm to 1.2 μm are tested at temperatures from 850 °C to 1000 °C which yields an in‐depth understanding of Sr diffusion through CGO thin films that may be of high scientific and technical interest for implementation of novel fuel cell materials. Sr is found to diffuse along column/grain boundaries in the CGO films but by modifying the film thickness and microstructure the breaking temperature of the barrier can be increased.
Do Marketing Margins Change with Food Scares? Examining the Effects of Food Recalls and Disease Outbreaks in the U.S. Red Meat Industry
Authors: Capps Oral , Colin‐Castillo Sergio , Hernandez Manuel A. 
Published: April 2013

ABSTRACTThis study examines the impact of different food scare events on marketing margins in the U.S. beef and pork industries. The authors analyze how market stresses induced by the Food Safety Inspection Service (FSIS) recalls and bovine spongiform encephalopathy (BSE) outbreaks affect price spreads and the extent of price transmission at the slaughter‐to‐wholesale and wholesale‐to‐retail levels. They use monthly national data for the period 1986–2008, which includes records of FSIS recalls of varying severity and BSE events in the United States and Canada. The authors account for immediate and delayed effects of food scares and for potential cross effects across industries and countries. The results indicate that beef and food recalls do not affect their corresponding price margins and overall food safety incidents have minor cross‐industry and cross‐country effects. However, BSE discoveries in the United States considerably affect marketing margins in the beef industry, particularly at the wholesale‐to‐retail level. Interestingly, subsequent discoveries had smaller impacts on price margins. Bovine spongiform encephalopathy outbreaks also appear to affect the extent of price transmission between wholesalers and retailers.
H∞ Control for a Class of Continuous‐time Switched Systems with State Constraints
Authors: Su Qingyu , Zhao Jun 
Published: April 2013

AbstractThis paper investigates the H∞ control problem for a class of continuous‐time switched systems subject to state constraints with an improved average dwell time. The state constraints are converted into state saturations by limiting the state in a unit hypercube. By employing this proposed improved average dwell time method, which takes into account different decay rates of a Lyapunov function related to an active subsystem according to whether the saturations occur or not, the resulting minimum of admissible average dwell time is smaller than the one of the standard average dwell time, which only considers the same decay rate regardless of whether the saturations occur or not. In addition, switched state feedback controllers are designed such that the closed‐loop switched system, subject to state constraints, is asymptotically stable and achieves a weighted L2‐gain. Sufficient conditions for H∞ control of the switched system with state constraints are derived before an application to a Pulse‐Width‐Modulation (PWM)‐driven boost converter is given to illustrate the applicability and the effectiveness of the proposed method.
A New Approach For Stability Analysis Of Time‐Dependent Switched Continuous‐Time Linear Systems
Authors: Xiang Weiming , Xiao Jian , Han Lu 
Published: April 2013

AbstractIn this paper, a new approach for stability analysis of time‐dependent switched linear systems is proposed. System equivalence is the main idea in this new approach, which derives a switched discrete linear parameter‐varying system from the switched continuous‐time linear switched system with interval dwell time, and the stability properties of the two corresponding systems are proved to be equivalent. Then, by applying a quadratic Lyapunov function approach for the equivalent switched discrete system, the stability of the switched continuous‐time linear system can be established without checking any average dwell time condition. Finally the computation complexity is analyzed, and mode incidence matrix is introduced to reduce the computation cost.
Raw material demand and sourcing options for the development of a bio‐based chemical industry in Europe.
Authors: Sanders Johan PM , Bos Harriëtte L 
Published: April 2013

AbstractIn this perspective it is shown that considerable amounts of fossil raw materials in the EU economy can be replaced by biomass by 2030 and 2050. Especially the additional demand from the chemical industry and part of the transportation fuels is investigated. Sufficient supply to accommodate the additional demand is achieved by a number of approaches: (i) by increasing the field yield of the main EU crops, including grassland; and (ii) by the application of biorefining technologies, which will enable efficient and economical use of biomass components for several purposes, for example, energy, animal feed, and chemical production. Especially the application of biorefinery technologies makes a broader crop choice possible, since all components present in the crop can be made to good use. It is concluded that in this way the EU can supply considerable amounts of its energy and raw material base, including the potential demand of the chemical industry, while at the same time decreasing its dependence on importing animal feed components from elsewhere. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Nothobranchius furzeri
Authors: Hartmann Nils , Reichwald Kathrin , Platzer Matthias , Englert Christoph 
Published: April 2013

AbstractDer Türkise Prachtgrundkärpfling Nothobranchius furzeri lebt in saisonalen Tümpeln Afrikas. Durch Diapausen übersteht er die zum Teil sehr langen Trockenzeiten. Nach dem Schlüpfen zeigt er ein sehr schnelles Wachstum und ist nach vier bis fünf Wochen geschlechtsreif. Bestimmte Stämme von N. furzeri weisen eine Lebensspanne von lediglich drei bis vier Monaten auf, was die kürzeste Lebensspanne für ein Wirbeltier darstellt, das im Labor gehalten werden kann. Trotz seiner kurzen Lebensspanne zeigt N. furzeri typische Altersmarker auf morphologischer, verhaltensbiologischer und molekularer Ebene. So zeigen alte Tiere beispielsweise eine Verkürzung der Telomere sowie einen Verlust der Anzahl und Aktivität der Mitochondrien. Erste Kreuzungsexperimente haben gezeigt, dass es mindestens vier Bereiche im Genom von N. furzeri gibt, die etwas mit der unterschiedlichen Lebensspanne zu tun haben.
Warum Spinnen (nur) acht Beine haben
Authors: Khadjeh Sara , Turetzek Natascha , Pechmann Matthias , Prpic Nikola‐Michael 
Published: April 2013

AbstractDie unterschiedliche Beinanzahl im Bauplan von Insekten und Spinnen wird als Modell genutzt, um Einblicke in die Genetik und Evolution von Bauplanunterschieden zu bekommen. Dabei spielen die Hox‐Gene eine wichtige Rolle: Insbesondere das Hox‐Gen Antennapedia hat während der Evolution offenbar seine Funktion und Interaktion mit bislang unbekannten Faktoren geändert.
New Limonoids from the Seeds of a Krishna Mangrove, Xylocarpus granatum
Authors: Chen Hongliang , Zhang Jing , Li Min‐Yi , Satyanandamurty Tirumani , Wu Jun 
Published: April 2013

AbstractTwo new mexicanolides, named granatumins H and I (1 and 2, resp.), and two phragmalins, named granatumins J and K (3 and 4, resp.), were isolated from the seeds of an Indian mangrove, Xylocarpus moluccensis, collected from the swamps of Krishna estuary, Andhra Pradesh. The structures of these limonoids were established on the basis of spectroscopic data. Granatumin J (3) is a highly oxidized phragmalin with five AcO groups, whereas granatumin K (4) is the first phragmalin found in nature with conjugated C(8)C(30) and C(14)C(15) bonds.
Chemical Composition and Antimicrobial Activity of Essential Oils from Chromolaena laevigata during Flowering and Fruiting Stages
Authors: Murakami Cynthia , Lago João H. G. , Perazzo Fábio F. , Ferreira Karen S. , Lima Marcos E. L. , Moreno Paulo R. H. , Young Maria C. M. 
Published: April 2013

AbstractThe chemical compositions and antimicrobial activities of essential oils from the leaves, stems, capitula, and cypselas of Chromolaena laevigata were evaluated at two different phenological stages, flowering and fruiting. Thirty‐eight compounds were identified in the crude oils by GC/MS. The sesquiterpene laevigatin was the major constituent of the leaf, capitulum, and cypsela oils, while the sesquiterpene spathulenol was the main component in the stem oils. The antimicrobial activities of the oils were evaluated against Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Stem oil obtained from Chromolaena laevigata during the fruiting stage generally showed the highest activity with minimum inhibitory concentration (MIC) values of 62.5 μg/ml against Candida albicans and S. aureus, and 500 μg/ml against P. aeruginosa and E. coli. Pure laevigatin exhibited MIC values of 500 and 125 μg/ml against C. albicans and S. aureus, respectively, indicating that this constituent could be responsible, at least in part, for the antimicrobial activities detected in the crude oils. More studies concerning the biological activities of isolated derivatives are required to improve our knowledge of the antimicrobial potential of volatile compounds present in native plants.
In vitro Leishmanicidal and Cytotoxic Activities of the Glycoalkaloids from Solanum lycocarpum (Solanaceae) Fruits
Authors: Abreu Miranda Mariza , Tiossi Renata Fabiane Jorge , da Silva Mariana Rosa , Rodrigues Kelly Cristina , Kuehn Christian Collins , Rodrigues Oliveira Luiz Gustavo , Albuquerque Sérgio , McChesney James Dewey , Lezama‐Davila Claudio Manuel , Isaac‐Marquez Angelica Patricia , Kenupp Bastos Jairo 
Published: April 2013

AbstractLeishmaniasis is an infection caused by a protozoan parasite of the genus Leishmania and is the second most prevalent parasitic protozoal disease after malaria in the world. We report the in vitro leishmanicidal activity on promastigote forms of Leishmania amazonensis and cytotoxicity, using LLCMK2 cells, of the glycoalkaloids from the fruits of Solanum lycocarpum, determined by colorimetric methods. The alkaloidic extract was obtained by acid‐base extraction; solamargine and solasonine were isolated by silica‐gel chromatography, followed by reversed‐phase HPLC final purification. The alkaloidic extract, solamargine, solasonine, as well as the equimolar mixture of the glycoalkaloids solamargine and solasonine displayed leishmanicidal activity against promastigote forms of L. amazonensis, whereas the aglycone solasodine was inactive. After 24 and 72 h of incubation, most of the samples showed lower cytotoxicities (IC50 6.5 to 124 μM) as compared to leishmanicidal activity (IC50 1.1 to 23.6 μM). The equimolar mixture solamargine/solasonine was the most active with an IC50 value of 1.1 μM, after 72 h. Likewise, solamargine was the most active after 24 h with an IC50 value of 14.4 μM, both in comparison with the positive control amphotericin B.
MMPREDOX/NO Interplay in Periodontitis and Its Inhibition with Satureja hortensis L. Essential Oil
Authors: Zeidán‐Chuliá Fares , Neves de Oliveira Ben‐Hur , Gursoy Mervi , Könönen Eija , Fonseca Moreira José Cláudio , Gursoy Ulvi K. , Uitto Veli‐Jukka 
Published: April 2013

AbstractSatureja hortensis L. is an aromatic plant with antibacterial and antibiofilm activities against periodontopathogens. Here, we attempted to find out whether the antioxidant properties of S. hortensis L. essential oil (EO) could be used to inhibit matrix metalloproteinase (MMP) activities and prevent the induction of cell death by a pro‐oxidant insult. First, a landscape analysis of MMP and REDOX/nitric oxide (NO)‐related genes was performed (MRN model), and array data from periodontitis patients were plotted over the newly developed model. Thereafter, the antigelatinolytic activity of S. hortensis L. EO and its preventive effect against hydrogen peroxide (H2O2)‐induced cell death were tested in vitro (HaCaT cells). Up‐regulation of MMP genes in the MRN network (except for MMP‐10, ‐15, ‐16, ‐20, ‐25, and ‐26) and differential expression of genes coding for antioxidant enzymes were found among others in periodontitis samples. MMP2 and MMP9 were central genes in the MRN network model. Moreover, treatments with 1 and 5 μl/ml of S. hortensis L. EO inhibited both MMP‐2 and MMP‐9 activities, and H2O2‐induced cell death in vitro. We concluded that S. hortensis L. EO could be a promising host‐modulating agent, since oxidative stress and excessive MMP expression/activity are typical hallmarks of periodontal pathogenesis.
Configurational Assignment of Secondary Hydroxyl Groups and Methyl Branches in Polyketide Natural Products through Bioinformatic Analysis of the Ketoreductase Domain
Authors: Kitsche Andreas , Kalesse Markus 
Published: April 2013

AbstractProfile hidden Markov models (HMMs) were used to predict the configuration of secondary alcohols and α‐methyl branches of modular polyketides. Based on the configurations of two chiral centers in these polyketides, 78 ketoreductases were classified into four different types of polyketide producers. The identification of positions that discriminate between these protein families was followed by fitting six profile HMMs to the data set and the corresponding subsets, to model the conserved regions of the protein types. Ultimately, the profile HMMs described herein predict protein subtypes based on the complete information‐rich region; consequently, slight changes in a multiple sequence alignment do not significantly alter the outcome of this classification method. Additionally, Viterbi scores can be used to assess the reliability of the classification.
Light‐Induced Reduction of Cuprous Oxide in an Environmental Transmission Electron Microscope
Authors: Cavalca Filippo , Laursen Anders B. , Wagner Jakob B. , Damsgaard Christian D. , Chorkendorff Ib , Hansen Thomas W. 
Published: April 2013

AbstractPhotocatalysts for solar fuel production are subject to intensive investigation as they constitute one viable route for solar energy harvesting. Cuprous oxide (Cu2O) is a working photocatalyst for hydrogen evolution but it photocorrodes upon light illumination in an aqueous environment. Environmental transmission electron microscopy (ETEM) makes it possible to obtain insight into the local structure, composition and reactivity of catalysts in their working environment, which is of fundamental interest for sustainable energy research and is essential for further material optimization. Herein, photoreduction of Cu2O is studied in situ using a dedicated TEM specimen holder for light illumination.
Ultrasensitive SERS Detection of Lysozyme by a Target‐Triggering Multiple Cycle Amplification Strategy Based on a Gold Substrate
Authors: He Peng , Zhang Yan , Liu Lijun , Qiao Wenping , Zhang Shusheng 
Published: April 2013

AbstractAn ultrasensitive surface enhanced Raman scattering (SERS) method has been designed to selectively and sensitively detect lysozyme. The gold chip as the detection substrate, the aptamer‐based target‐triggering cascade multiple cycle amplification, and gold nanoparticles (AuNPs) bio‐barcode Raman probe enhancement on the gold substrate are employed to enhance the SERS signals. The cascade amplification process consists of the nicking enzyme signaling amplification (NESA), the strand displacement amplification (SDA), and the circular‐hairpin‐assisted exponential amplification reaction (HA‐EXPAR). With the involvement of an aptamer‐based probe, two amplification reaction templates, and a Raman probe, the whole circle amplification process is triggered by the target recognition of lysozyme. The products of the upstream cycle (NESA) could act as the “DNA trigger” of the downstream cycle (SDA and circular HA‐EXPAR) to generate further signal amplification, resulting in the immobility of abundant AuNPs Raman probes on the gold substrate. “Hot spots” are produced between the Raman probe and the gold film, leading to significant SERS enhancement. This detection method exhibits excellent specificity and sensitivity towards lysozyme with a detection limit of 1.0×10−15 M. Moreover, the practical determination of lysozyme in human serum demonstrates the feasibility of this SERS approach in the analysis of a variety of biological specimens.
Precise Control of Intramolecular Charge‐Transport: The Interplay of Distance and Conformational Effects
Authors: Schubert Christina , Wielopolski Mateusz , Mewes Lars‐Hendrik , de Miguel Rojas Gustavo , van der Pol Cornelia , Moss Kathryn C. , Bryce Martin R. , Moser Jacques E. , Clark Timothy , Guldi Dirk M. 
Published: April 2013

AbstractA new series of donor–bridge–acceptor (D–B–A) compounds consisting of π‐conjugated oligofluorene (oFL) bridges between a ferrocene (Fc) electron‐donor and a fullerene (C60) electron‐acceptor have been synthesized. In addition to varying the length of the bridge (i.e., mono‐ and bi‐fluorene derivatives), four different ways of linking ferrocene to the bridge have been examined. The Fc moiety is linked to oFL: 1) directly without any spacer, 2) by an ethynyl linkage, 3) by a vinylene linkage, and 4) by a p‐phenylene unit. The electronic interactions between the electroactive species have been characterized by cyclic voltammetry, absorption, fluorescence, and transient absorption spectroscopy in combination with quantum chemical calculations. The calculations reveal exceptionally close energy‐matching between the Fc and the oFL units, which results in strong electronic‐coupling. Hence, intramolecular charge‐transfer may easily occur upon exciting either the oFLs or Fcs. Photoexcitation of Fc–oFL–C60 conjugates results in transient radical‐ion‐pair states. The mode of linkage of the Fc and FL bridge has a profound effect on the photophysical properties. Whereas intramolecular charge‐separation is found to occur rather independently of the distance, the linker between Fc and oFL acts (at least in oFL) as a bottleneck and significantly impacts the intramolecular charge‐separation rates, resulting in beta values between βCS 0.08 and 0.19 Å−1. In contrast, charge recombination depends strongly on the electron‐donor–acceptor distance, but not at all on the linker. A value of βCR (0.35±0.01 Å−1) was found for all the systems studied. Oligofluorenes prove, therefore, to be excellent bridges for probing how small structural variations affect charge transport in D–B–A systems.
An Efficient Method to Separate Sc3N@C80Ih and D5h Isomers and Sc3N@C78 by Selective Oxidation with Acetylferrocenium [Fe(COCH3C5H4)Cp]+
Authors: Cerón Maira R. , Li Fang‐Fang , Echegoyen Luis 
Published: April 2013

AbstractBased on the different oxidation potentials of endohedral fullerenes Sc3N@C80 Ih and D5h and Sc3N@C78, an efficient and useful method that avoids HPLC has been developed for their separation. Selective chemical oxidation of the Sc3N@D5h‐C80 isomer and Sc3N@C78 by using an acetylferrocenium salt [Fe(COCH3C5H4)Cp]+ followed by column chromatographic separation and reduction with CH3SNa resulted in the isolation of pure Sc3N@Ih‐C80, Sc3N@C78, and a mixture of Sc3N@D5h‐C80 and Sc3N@C68.