bluuebunny/crossref_metadata_2025_split huggingface dataset:
A toughened PLA/Nanosilica composite obtained in the presence of epoxidized soybean oil
Authors: Xiong Zhu , Dai Xinyan , Na Haining , Tang Zhaobin , Zhang Ruoyu , Zhu Jin 
Published: July 2014

ABSTRACTIn this manuscript, a toughened PLA/nanosilica composite with good storage stability was obtained in the presence of the epoxidized soybean oil (ESO). The composite was fabricated via a twin‐screw extruder, and characterized by the FTIR, selective distribution test, and SEM. The surface of nanosilica was modified by the ESO through the chemical bonding, and this rendered the nanosilica to selectively localize in ESO droplets in the composite. As a result, the PLA/nanosilica composite was changed from brittleness to ductility with the addition of ESO. For example, the elongation and notched impact strength of the PLA/silica/ESO nanocomposite with 5 wt % nanosilica and 15 wt % ESO were ∼42% and ∼11 KJ/m2, respectively, which were much higher than neat PLA or PLA/nanosilica composite without ESO. Furthermore, the change of the brittle fracture of PLA into ductile fracture was investigated by SEM micrographs in detail. A possible toughening mechanism was also proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41220.
Fabrication and properties of poly(l‐lactide) nanofibers via blend sea‐island melt spinning
Authors: Zhang Xiuqin , Jin Gaoling , Ma Wenjuan , Meng Lingyan , Yin Huihui , Zhu Zhiguo , Dong Zhenfeng , Wang Rui 
Published: July 2014

ABSTRACTPoly(l‐lactide) (PLLA) nanofibers were prepared by melt extrusion of immiscible blends of PLLA/low density polyethylene (LDPE) and subsequent removal of the LDPE matrix from the blend fibers. The effect of blends composition and draw ratio on the phase structure of the blend fibers, crystallization, mechanical properties, and the diameter of the PLLA nanofibers was investigated. It is found that the diameter of the PLLA phase gradually increases with the increase of PLLA content. With the variation of PLLA content from 50 to 60 wt %, the average diameter of acquired PLLA nanofibers changes from 119 to 153 nm under the draw ratio of 1.5. When further increasing the content of PLLA to 65%, it is difficult to acquire PLLA nanofibers due to the poor dissolving properties between PLLA and LDPE components. Oriented PLLA nanofibers with the average diameter of 92 nm can be fabricated from PLLA/LDPE (50/50, wt %) blends under the draw ratio of 2. The present results suggest that it is possible to acquire polymer nanofibers with high output using blend sea‐island melt spinning. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41228.
Thermodriven Micrometer‐Scale Aqueous‐Phase Separation of Amphiphilic Oligoethylene Glycol Analogues
Authors: Kawasaki Shunichi , Muraoka Takahiro , Obara Haruki , Ishii Takerou , Hamada Tsutomu , Kinbara Kazushi 
Published: July 2014

AbstractThermoresponsive materials with a lower critical solution temperature (LCST) are receiving growing attention, of which examples of non‐polymeric small molecules are limited. Monodisperse oligoethylene glycol amphiphiles that contain aromatic units with a LCST in water have been developed and applied to peptide extraction. Concentration‐dependent hysteretic transmittance changes were observed in response to temperature elevation and reduction. Dynamic light scattering measurements and phase contrast microscopy revealed the formation of micrometer‐sized aggregates upon heating at a concentration above 5.0 mM; these aggregates self‐assembled to form larger aggregates upon cooling before dissolution. The “interaggregate” interactions are likely to cause the hysteretic behavior. As an application of this thermodriven phase separation, selective extraction of peptide fragments containing high percentages of hydrophobic and aromatic amino acid residues was successfully demonstrated.
Pyrene‐Based Fluorescent Supramolecular Hydrogel: Scaffold for Energy Transfer
Authors: Mukherjee Subrata , Kar Tanmoy , Kumar Das Prasanta 
Published: July 2014

AbstractThe self‐assembled gelation of an amino‐acid‐based low molecular weight gelator having a pyrene moiety at the N terminus and a bis‐ethyleneoxy unit linked with succinic acid at the C terminus is reported. This amphiphile is capable of gelating binary mixtures (1/3 v/v) of CH3CN/water, DMSO/water, and DMF/water, and the minimum gelation concentration (MGC) varied from 0.2 to 0.3 % w/v. The sodium salt of the amphiphile efficiently gelates water with an MGC of 1.5 % w/v. The participation of different noncovalent interactions in supramolecular gelation by formation of fibrillar networks was investigated by spectroscopic and microscopic methods. High mechanical strength of the supramolecular gels is indicated by storage moduli on the order of 103 Pa. The hydrogel was utilized for energy transfer, whereby inclusion of only 0.00075 % w/v of acridine orange resulted in about 50 % quenching of the fluorescence intensity of the gel through fluorescence resonance energy transfer.
Design of H∞ static output feedback control for discrete‐time systems with limited actuator
Authors: Li Yeng‐Fang 
Published: July 2014

AbstractIn this paper, static output feedback (SOF) control analysis and synthesis are conducted for linear discrete‐time systems subject to actuator saturation with an H∞ setting. Typically, the SOF problem is nonconvex; the existence of static output feedback control can be expressed in terms of the solvability of bilinear matrix inequalities (BMIs). Because these BMIs are difficult to solve, they are usually solved by transforming the BMI problem into an iterative linear matrix inequality (ILMI) problem. The actuator saturation problem is also considered since the driving capacity of an actuator is limited in practical applications. Using the classical approach, singular value decomposition (SVD), the H∞ SOF controller design problem for systems with actuator saturation can be expressed in terms of an eigenvalue problem (EVP). The coordination between the minimization of the attenuation level of the H∞ performance and the maximization of the estimation of the region of attraction are considered in our approach in the solution of the proposed EVP. Finally, some numerical examples are given to describe the proposed design procedure.
A New Derivation of the Cubature Kalman Filters
Authors: Zhang Xin‐Chun , Teng Yun‐Long 
Published: July 2014

ABSTRACTThis paper investigates the cubature Kalman filtering (CKF) for nonlinear dynamic systems. This third‐degree rule based filter employs a spherical‐radial cubature rule to numerically compute the integrals encountered in nonlinear filtering problems, thereby removing the requirements of explicitly computing the Jacobians. The cubature rule, however, requires computing the intractable integrals over a high‐dimensional spherical region for multidimensional applications. Moreover, the cubature formula that has been used to construct the spherical cubature formula has some demerits, most notably its inconvenient properties in computation and low estimation accuracy. Aimed at these issues, a general class of CKFs that uses only cubature rules is derived in this paper. It can be shown that the conventional CKF is a special case of the proposed algorithm. The paper also includes higher‐degree CKFs, especially two representative types of the fifth‐degree CKFs. Performance of the proposed algorithms is demonstrated via two target tracking problems. The experimental results, presented herein, illustrate the superior performance of higher‐degree CKFs to conventional nonlinear filters.
Decentralized Output Feedback Protocol for Consensus Control of a Class of Nonlinear Dynamics Networks
Authors: Li Zhenxing , Ji Haibo , Sheng Jie 
Published: July 2014

AbstractThis paper studies the consensus control for multi‐agent systems with nonlinear functions satisfying the sector condition. To achieve consensus, we design a distributed output feedback protocol with an undetermined system matrix, and derive some conditions in terms of linear matrix inequalities (LMIs) to guarantee consensus of all agents' states. Furthermore, by solving three LMIs, the system matrix of the output feedback protocol is designed. Finally, we provide a simulation to show the effectiveness of the proposed consensus protocol.
Adaptive Dual Control of Discrete‐Time Lqg Problems with Unknown‐But‐Bounded Parameter
Authors: Qian Fucai , Huang Jiaoru , Liu Ding , Hu Shaolin 
Published: July 2014

AbstractThe dual control for a class of discrete‐time linear‐quadratic Gaussian (LQG) problems is studied in this paper, where there exist unknown‐but‐bounded parameter uncertainties both in the state equation and the observation equation. It is assumed that the unknown parameter belongs to a known bounded interval. To achieve the adaptive dual control, a subdivision for the continuous bounded interval is used, thus, the computational tractability is ensured. Based on such subdivision, the adaptive dual controller developed can learn a more accurate interval that contains the true value of the unknown parameter with a learning error given in advance. The performance of the controller is illustrated with two examples.
Immunological tools: Engaging students in the use and analysis of flow cytometry and enzyme‐linked immunosorbent assay (ELISA)
Authors: Ott Laura E. , Carson Susan 
Published: July 2014

AbstractFlow cytometry and enzyme‐linked immunosorbent assay (ELISA) are commonly used techniques associated with clinical and research applications within the immunology and medical fields. The use of these techniques is becoming increasingly valuable in many life science and engineering disciplines as well. Herein, we report the development and evaluation of a novel half‐semester course that focused on introducing undergraduate and graduate students to advance conceptual and technical skills associated with flow cytometry and ELISA, with emphasis on applications, experimental design, and data analysis. This course was offered in the North Carolina State University Biotechnology Program over three semesters and consisted of weekly lectures and laboratories. Students performed and/or analyzed flow cytometry and ELISA in three separate laboratory exercises: (1) identification of transgenic zebrafish hematopoietic cells, (2) analysis of transfection efficiency, and (3) analysis of cytokine production upon lipopolysaccharide stimulation. Student learning outcomes were achieved as demonstrated by multiple means of assessment, including three laboratory reports, a data analysis laboratory practicum, and a cumulative final exam. Further, anonymous student self‐assessment revealed increased student confidence in the knowledge and skill sets defined in the learning outcomes. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(5):382–397, 2014.
Guaiacol peroxidase zymography for the undergraduate laboratory
Authors: Wilkesman Jeff , Castro Diana , Contreras Lellys M. , Kurz Liliana 
Published: July 2014

AbstractThis laboratory exercise presents a novel way to introduce undergraduate students to the specific detection of enzymatic activity by electrophoresis. First, students prepare a crude peroxidase extract and then analyze the homogenate via electrophoresis. Zymography, that is, a SDS‐PAGE method to detect enzyme activity, is used to specifically detect peroxidase activity and furthermore, to analyze the total protein profile. After the assay, students may estimate the apparent molecular mass of the enzyme and discuss its structure. After the 4‐h experiment, students gain knowledge concerning biological sample preparation, gel preparation, electrophoresis, and the importance of specific staining procedures for the detection of enzymatic activity. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(5):420–426, 2014.
A Generalizable DNA‐Catalyzed Approach to Peptide–Nucleic Acid Conjugation
Authors: Chu Chih‐Chi , Wong On Yi , Silverman Scott K. 
Published: July 2014

AbstractWe report DNA catalysts (deoxyribozymes) that join tyrosine‐containing peptides to RNA and DNA in one step and without requiring protecting groups on either the peptide or the nucleic acid. Our previous efforts towards this goal required tethering the peptide to a DNA anchor oligonucleotide. Here, we established direct in vitro selection for deoxyribozymes that use untethered, free peptide substrates. This approach enables imposition of selection pressure via reduced peptide concentration and leads to preparatively useful lower apparent Km values of ∼100 μM peptide. Use of phosphorimidazolide (Imp) rather than triphosphate as the electrophile enables reactivity of either terminus (5′ or 3′) of both RNA and DNA. Our findings establish a generalizable means of joining unprotected peptide to nucleic acid in one step by using DNA catalysts identified by in vitro selection.
Post‐ harvest consideration factors for microRNA research in cellular, tissue, serum and plasma samples
Authors: Chiang Vic Shao‐Chih 
Published: July 2014

AbstractMicroRNA plays important regulatory roles on the genetic network which provides researchers with valuable novel mechanistic directions and perspectives for applications in a wide variety of fields. Despite pertinent insight gained from messenger RNA, microRNAs possess distinct biochemical properties that emphasize the need for independent research to be conducted that addresses specifically microRNA handling. This review provides a brief summary on the various factors at post‐sample harvesting stages with focus on microRNA from cellular, tissue, plasma and serum samples. It incorporates an up‐to‐date discussion on the isolation methods, quality control, profiling methods and other post‐harvesting factors in microRNA research.
Melanocyte migration is influenced by E‐cadherin‐dependent adhesion of keratinocytes in both two‐ and three‐dimensional in vitro wound models
Authors: Keswell Dheshnie , Kidson Susan H. , Davids Lester M. 
Published: July 2014

AbstractDuring wound healing, melanocytes are required to migrate into the wounded area that is still in the process of re‐construction. The role and behaviour of melanocytes during this process is poorly understood, that is, whether melanocyte migration into the wound is keratinocyte‐dependent or not. This paper attempts, through the use of both two‐ and three‐dimensional in vitro models, to understand the role and behaviour of melanocytes during the process of wound healing. In addition, it sheds light on whether keratinocytes influence/contribute toward melanocyte migration and ultimately wound healing. Scratch assays were performed to analyse migration and Western blot analyses measured cellular E‐cadherin expression. Immunohistochemistry was used to analyse the in vivo 3D wound healing effect. Scratch assays performed on co‐cultures of melanocytes and keratinocytes demonstrated that melanocytes actively migrated, with the use of their dendrites, into the scratch ahead of the proliferating keratinocyte sheet. Migration of the melanocyte into the wound bed was accompanied by loss of attachment to keratinocytes at the wound front with concomitant downregulation of E‐cadherin expression as observed through immunocytochemistry. This result suggests that, in vitro, melanocyte migration occurs independently of keratinocytes but that the migration is influenced by keratinocyte E‐cadherin expression. We now demonstrate that melanocyte migration during re‐pigmentation is an active process, and suggest that targeting of mechanisms involved in active melanocyte migration (e.g. the melanocyte dendrite) may enhance the re‐pigmentation process.
Lithium chloride suppresses LPS‐mediated matrix metalloproteinase‐9 expression in macrophages through phosphorylation of GSK‐3β
Authors: Kim Sooho , Bong Naeun , Kim Ok Soo , Jin JunYup , Kim Dong‐Eog , Lee Dong Kun 
Published: July 2014

AbstractAbnormal degradation of matrix components due to dysregulated expression of matrix metalloproteinase (MMP)‐9 in macrophages has been linked to progression of acute cerebral ischemia and atherosclerosis. We report that lithium chloride (LiCl) or CHIR99021, inhibitors of Wnt signaling pathway, enhance phosphorylation of glycogen synthase kinase‐3beta and suppress lipopolysaccharide‐mediated upregulation of MMP‐9 expression in murine macrophage RAW264.7 cells in a dose‐dependent manner. Suppression of MMP‐9 expression by LiCl or CHIR99021 did not result after inhibition of kinases involved in NFκB or AP‐1 family proteins, but from changes in the activity of histone deacetylases. Beneficial effects on atherosclerosis or cerebral ischemia in animal studies caused by LiCl may be in part explained by the suppression of MMP‐9 gene expression.
Carbon Quantum Dot/Silver Nanoparticle/Polyoxometalate Composites as Photocatalysts for Overall Water Splitting in Visible Light
Authors: Liu Juan , Zhang Hengchao , Tang Di , Zhang Xing , Yan Likai , Han Yuzhi , Huang Hui , Liu Yang , Kang Zhenhui 
Published: July 2014

AbstractThe design of photocatalysts for overall water splitting in visible light remains a huge challenge. Carbon quantum dots (CQDs)/Ag/Ag3PW12O40 nanocomposites have high photocatalytic activities for overall water splitting in visible light without electron acceptors or hole scavengers. In the present system, H2 evolution was performed on Ag particles. O2 evolution appears to be a result of the oxidation of H2O on the valence band of Ag3PW12O40, which is enhanced by promoted electron‐transfer events at hybrid interfaces of the polyoxometalates and CQDs. The synergistic effects of CQDs, Ag, and Ag3PW12O40 enable the design of a water‐splitting catalyst with a remarkably improved efficiency (with an active region of λ<650 nm; apparent quantum yield ≈4.9 % at 480 nm) and operational stability.
A New Combustion Route to Synthesize Mixed Valence Vanadium Oxide Heterojunction Composites as Visible‐Light‐Driven Photocatalysts
Authors: Jiang Baojiang , Peng Xiuxia , Qu Yang , Wang Hong , Tian Chungui , Pan Qingjiang , Li Mingxia , Zhou Wei , Fu Honggang 
Published: July 2014

AbstractThe fabrication of a semiconductor heterojunction photocatalyst is a key aim of the visible light photocatalytic field owing to its central role in the enhancement of photogenerated charge separation and quantum efficiency. Herein, a new mixed valence vanadium oxide composite with the VO2@V6O13 heterojunction is fabricated through the facile and direct combustion of an ethanol solution composed of ammonium metavanadate and diethyl imidazole. XRD and TEM analyses reveal the structural evolution at the interface between VO2 and V6O13, which manipulates the electronic structure of the composites. The composition and chemical state of the composites are obtained by using X‐ray photoelectron spectroscopy. In addition, the detailed energy band structure has been confirmed by the analysis of the UV/Vis absorption spectra and X‐ray photoelectron spectroscopy valence band spectra. The mixed valence vanadium oxides readily narrow their energy gap (1.4–2.5 eV), which enables the efficient utilization of visible light and the improvement in charge separation rate. Thus, the photocatalysts with the VO2@V6O13 heterojunction demonstrate improved photocatalytic activity and structural stability in the degradation of atrazine pesticide under visible light irradiation, which is an effective solution for the problem of remnant pesticides for future agriculture. Furthermore, this facile and straightforward method has promising applications in the fabrication of other heterostructure photocatalysts.
Oxidative Grafting of a Redox‐Molecule‐Based Ionic Liquid onto an Electrode Surface: Anion Exchange within a Layer
Authors: Gómez‐Mingot Maria , Bui‐Thi‐Tuyet Van , GaëlleTrippé‐Allard  , Ghilane Jalal , Randriamahazaka Hyacinthe 
Published: July 2014

AbstractThe surface modification of carbon electrodes using an imidazolium‐based ionic liquid bearing a redox functionality is investigated. Electrochemical oxidation of N‐(2‐aminoethyl)‐N‐(4‐nitrophenylethylimidazolium) bromide onto a glassy carbon electrode leads to the immobilization of nitrophenyl‐imidazolium layers. The presence of this layer is evidenced by following the electrochemical signal of the attached redox moieties. Furthermore, the modified electrode behavior is studied in the presence of redox probes, from which it is concluded that the generated layer is very thin and/or less dense, probably due to the specific arrangement of the positively charged imidazolium. In addition, we investigate the capability of performing anion exchange within the immobilized layer by simple immersion of the electrode in the ionic liquid. X‐ray photoelectron analyses evidence the occurrence of the exchange within the layer and confirm the presence of attached nitrophenyl‐imidazolium.
Revealing the Active Intermediates in the Oxidation of Formic Acid on Au and Pt(111)
Authors: Gao Wang , Song Er Hong , Jiang Qing , Jacob Timo 
Published: July 2014

AbstractThe mechanisms of formic acid (HCOOH) oxidation on Au(111) under gas‐phase and electrochemical conditions was studied by using density functional theory and then compared with the analogous processes on Pt(111). Our results demonstrate that a mechanism involving a single intermediate molecule is preferred on both Au and Pt(111). Furthermore, under gas‐phase conditions, HCOOH oxidation proceeds through the same mechanism (formate pathway) on Au and Pt(111), whereas under electrochemical conditions, it can take place through significantly different mechanisms (formate and/or direct pathways), depending on the applied electrode potential. Our calculations help to rationalize conflicting experimental explanations and are crucial for understanding the mechanism of this fundamental (electro‐)catalytic process.
Chemoselective Phototransformation of CH Bonds on a Polymer Surface through a Photoinduced Cerium Recycling Redox Reaction
Authors: Huang Zhenhua , Wu Zhengfang , Yang Peng , Yang Wantai 
Published: July 2014

AbstractIt is generally accepted that Ce4+ is unable to directly oxidize unreactive alkyl CH bonds without the assistance of adjacent polar groups. Herein, we demonstrate in our newly developed confined photochemical reaction system that this recognized issue may be challenged. As we found, when a thin layer of a CeCl3/HCl aqueous solution was applied to a polymeric substrate and the substrate subjected to UV irradiation, Ce3+ was first photooxidized to form Ce4+ in the presence of H+, and the in situ formed Ce4+ then performs an oxidation reaction on the CH bonds of the polymer surface to form surface‐carbon radicals for radical graft polymerization reactions and functional‐group transformations, while reducing to Ce3+ and releasing H+ in the process. This photoinduced cerium recycling redox (PCRR) reaction behaved as a biomimetic system in an artificial recycling reaction, leading to a sustainable chemical modification strategy for directly transforming alkyl CH bonds on polymer surfaces into small‐molecule groups and polymer brushes. This method is expected to provide a green and economical tool for industrial applications of polymer‐surface modification.
Strong Induced‐Fit Binding of Viologen and Pyridine Derivatives in Adjustable Porphyrin Cavities
Authors: Deutman Alexander B. C. , Smits Jan M. M. , de Gelder René , Elemans Johannes A. A. W. , Nolte Roeland J. M. , Rowan Alan E. 
Published: July 2014

AbstractThe synthesis and binding properties of new porphyrin cage compounds consisting of a rigid diphenylglycoluril part, which is connected via flexible bis(ethyleneoxy) spacers to a (metallo)porphyrin “roof”, are reported. Binding of viologen guests and pyridine ligands in these porphyrin cages are accompanied by significant conformational reorganizations of the hosts. Despite these structural changes, association constants are still very high, revealing that not only receptors that bind guests according to a lock‐and‐key mechanism but also those that bind guests by an induced‐fit mechanism can exhibit strong binding.