bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of fiber surface treatment on mechanical performance of Xanthoceras sorbifolia bunge husk fibers/PP composites
Authors: Yao Xu‐Dan , Liu Dong‐Yan , Sui Guo‐Xin 
Published: July 2014

ABSTRACTThe PP Composites containing Xanthoceras sorbifolia Bunge husks fibers with different surface treatments were prepared. The mechanical properties such as tensile properties and impact properties of the composites were investigated. It is revealed that the composites with fibers treated by alkali and the following treatments of silane coupling agents KH570, titanate coupling agent JN‐9A, acetic anhydride, MAPP, or bleach, all performed higher in tensile properties than that with untreated fibers, while lower in impact properties. Meanwhile, all treated fibers performed better thermal stability than untreated fibers. The fibers treated by alkali followed by KH570 treatment were added into PP with different contents. It is found that as the fiber content increases, the elastic modulus and impact strength of the composites increase sharply at first followed by a decrease, while the tensile strength decrease initially and increase with a peak at 10%, then decrease continuously. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41217.
Photo‐ and pH‐Tunable Multicolor Fluorescent Nanoparticle‐Based Spiropyran‐ and BODIPY‐Conjugated Polymer with Graphene Oxide
Authors: Sharker Shazid Md. , Jeong Chan Jin , Kim Sung Min , Lee Jung‐Eun , Jeong Ji Hoon , In Insik , Lee Haeshin , Park Sung Young 
Published: July 2014

AbstractWe report a stimuli‐responsive fluorescent nanomaterial, based on graphene oxide coupled with a polymer conjugated with photochromic spiropyran (SP) dye and hydrophobic boron dipyrromethane (BODIPY) dye, for application in triggered target multicolor bioimaging. Graphene oxide (GO) was reduced by catechol‐conjugated polymers under mildly alkaline conditions, which enabled to formation of functionalized multicolor graphene nanoparticles that can be induced by irradiation with UV light and by changing the pH from acidic to neutral. Investigation of these nanoparticles by using AFM, fluorescence emission, and in vitro cell and in vivo imaging revealed that they show different tunable colors in bioimaging applications and, more specifically, in cancer‐cell detection. The stability, biocompatibility, and quenching efficacy of this nanocomposite open a different perspective for cell imaging in different independent colors, sequentially and simultaneously.
Through‐Space Conjugated Molecular Wire Comprising Three π‐Electron Systems
Authors: Morisaki Yasuhiro , Kawakami Naoya , Shibata Shotaro , Chujo Yoshiki 
Published: July 2014

AbstractA [2.2]paracyclophane‐based through‐space conjugated oligomer comprising three π‐electron systems was designed and synthesized. The arrangement of three π‐conjugated systems in an appropriate order according to the energy band gap resulted in efficient unidirectional photoexcited energy transfer by the Förster mechanism. The energy transfer efficiency and rate constants were estimated to be >0.999 and >1012 s−1, respectively. The key point for the efficient energy transfer is the orientation of the transition dipole moments. The time‐dependent density functional theory (TD‐DFT) studies revealed the transition dipole moments of each stacked π‐electron system; each dipole moment was located on the long axis of each stacked π‐electron system. This alignment of the dipole moments is favorable for fluorescence resonance energy transfer (FRET).
Optimal Control of Midazolam Infusion for Post Operative Patients in Intensive Care Units
Authors: Padmanabhan Regina , Meskin Nader , Haddad Wassim M. 
Published: July 2014

AbstractThe critical task of anesthesia administration demands optimal drug titration by considering patient‐specific features and sedation requirements. Though there exist several sedation assessment monitors, physicians still largely rely on subjective sedation scoring systems. This paper presents an optimal infusion controller for the continuous infusion of midazolam along with the analgesic fentanyl. Specifically, we extend the convex optimization‐based optimal drug dosing regimen for propofol to midazolam. We additionally propose an alternative optimization approach using the Kullback‐Leibler divergence measure of two probability distributions. It is shown that by using the new proposed approach one can achieve the desired sedation level by using less drug infusion in comparison with previous methods. A nonlinear two‐compartment model is used to describe the pharmacokinetics of midazolam and a stochastic pharmacodynamic model is used that utilizes the modified Ramsay sedation scoring method to link the plasma drug concentration with the effective probabilistic sedation level.
Gain‐Scheduled H∞ Control for Tensor Product Type Polytopic Plants
Authors: Chumalee Sunan , Whidborne James F. 
Published: July 2014

AbstractA tensor product (TP) model transformation is a recently proposed technique for transforming a given linear parameter‐varying (LPV) model into polytopic model form, for which there are many methods that can be used for controller design. This paper proposes an alternative approach to the design of a gain‐scheduled output feedback H∞ controller with guaranteed L2‐gain parameter‐dependent performance for a class of TP type polytopic models using parameter‐dependent Lyapunov functions where the linear matrix inequalities (LMIs) need only to be evaluated at all vertices of the system state‐space model matrices and the variation rate of the scheduled parameters. In addition, a construction technique of the intermediate controller variables is also proposed as a matrix‐valued function in the polytopic coordinates of the scheduled parameters. The performance of the proposed approach is tested on a missile autopilot design problem. Furthermore, nonlinear simulation results show the effectiveness of these proposed techniques.
Effect of Improved Tracking for Atomic Force Microscope on Piezo Nonlinear Behavior
Authors: Rana Md. Sohel , Pota Hemanshu R. , Petersen Ian R. , Habibullah Habib 
Published: July 2014

AbstractNanotechnology is an area of modern science which deals with the control of matter at dimensions of 100 nm or less. In recent years, of all the available microscopy techniques, atomic force microscopy (AFM) has proven to be extremely versatile as an investigative tool in this field. However the performance of AFM is significantly limited by the effects of hysteresis, creep, cross‐coupling, and vibration in its scanning unit, the piezoelectric tube scanner (PTS). This article presents the design and experimental implementation of a single‐input single‐output (SISO) model predictive control (MPC) scheme with a vibration compensator which is based on an identified model of the PTS. The proposed controller provides an AFM with the capability to achieve improved tracking and results in compensation of the nonlinear effects. The experimental results, which compare the tracking performances of the proposed controller for different reference signals, highlight the usefulness of the proposed control scheme.
Active Disturbance Rejection Control of a Magnetic Suspension System
Authors: Beltran‐Carbajal Francisco , Valderrabano‐Gonzalez Antonio , Favela‐Contreras Antonio R. , Rosas‐Caro Julio Cesar 
Published: July 2014

AbstractThis paper proposes a novel output feedback control scheme for robust stabilization and tracking tasks in a magnetic suspension system. Active disturbance rejection control, differential flatness and on‐line asymptotic disturbance estimation are properly used for the proposed control synthesis. The controlled system is subjected to a wide spectrum of unknown significant matched and unmatched disturbances due to external forces and voltages, parametric uncertainties, control and state‐dependent perturbations and possibly input unmodeled dynamics. The effectiveness and robustness of the proposed active disturbance control scheme is verified by computer simulations for the robust tracking of a rest‐to‐rest reference position trajectory specified to firstly stabilize the suspended mass at a desired vertical position and next transfer it to another equilibrium position for both continuous and switched control voltage signals.
Using a microbial physiologic and genetic approach to investigate how bacteria sense physical stimuli
Authors: Mussi María Alejandra , Actis Luis A. , de Mendoza Diego , Cybulski Larisa E. 
Published: July 2014

AbstractA laboratory exercise was designed to illustrate how physical stimuli such as temperature and light are sensed and processed by bacteria to elaborate adaptive responses. In particular, we use the well‐characterized Des pathway of Bacillus subtilis to show that temperature modulates gene expression, resulting ultimately in modification of the levels of unsaturated fatty acids required to maintain proper membrane fluidity at different temperatures. In addition, we adapt recent findings concerning the modulation by light of traits related to virulence such as motility and biofilm formation in the chemotropic bacterium Acinetobacter baumannii. Beyond the theoretical background that this activity provides regarding sensing of environmental stimuli, the experimental setup includes approaches derived from classic genetics, microbiology, and biochemistry. The incorporation of these kind of teaching and training activities in middle‐advanced Microbiology or Bacterial Genetics courses promotes acquisition of general and specific techniques and improves student's comprehension of scientific literature and research. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(5):427–434, 2014.
Inhibition of epidermal growth factor signaling by the cardiac glycoside ouabain in medulloblastoma
Authors: Wolle Daniel , Lee Seung Joon , Li Zhiqin , Litan Alisa , Barwe Sonali P. , Langhans Sigrid A. 
Published: July 2014

AbstractEpidermal growth factor (EGF) signaling regulates cell growth, proliferation, and differentiation. Upon receptor binding, EGF triggers cascades of downstream signaling, including the MAPK and phosphoinositide‐3‐kinase (PI3K)/Akt signaling pathways. Aberrant expression/activation of EGFR is found in multiple human cancers, including medulloblastoma, the most prevalent pediatric brain cancer, and often has been associated with metastasis, poor prognosis, and resistance to chemotherapy. Na,K‐ATPase is an ion pump well known for its role in intracellular ion homeostasis. Recent studies showed that Na,K‐ATPase also functions as a signaling platform and revealed a role in EGFR, MAPK, and PI3K signaling. While both EGFR and Na,K‐ATPase seem to modulate similar signaling pathways, cardiac glycosides that are steroid‐like inhibitors of Na,K‐ATPase, exhibit antiproliferative and proapoptotic properties in cancer cells. Thus, we sought to better understand the relationship between EGF and cardiac glycoside signaling. Here, we show that in medulloblastoma cells, both EGF and ouabain activate Erk1/2 and PI3K/Akt signaling. Nevertheless, in medulloblastoma cells ouabain did not transactivate EGFR as has been reported in various other cell lines. Indeed, ouabain inhibited EGF‐induced Erk1/2 and Akt activation and, moreover, prevented EGF‐induced formation of actin stress fibers and cell motility, probably by activating a stress signaling response. Na,K‐ATPase has been proposed to act as a signaling scaffold and our studies suggest that in medulloblastoma cells Na,K‐ATPase might act as a check point to integrate EGF‐associated signaling pathways. Thus, Na,K‐ATPase might serve as a valid target to develop novel therapeutic approaches in tumors with aberrant activation of the EGFR signaling cascades.
High‐Throughput Bead‐Based Identification of Structure‐Switching Aptamer Beacons
Authors: Trevino Simon G. , Levy Matthew 
Published: July 2014

AbstractWe describe a new platform to identify structure‐switching DNA beacon aptamers, which detect small molecules in a specific manner. By clonally amplifying a DNA library designed to fluoresce in response to binding events onto microbeads, aptamer beacons can be selected by stringent fluorescence‐assisted sorting. We validated this method by isolating known and novel anti‐steroid aptamers from two separate DNA libraries that were structurally enriched with three‐way junctions. Importantly, aptamers were retrieved in only a few (three) rounds of selection by this approach and did not require further optimization, significantly streamlining the process of beacon development.
Ectopic expression of DAZL gene in goat bone marrow‐derived mesenchymal stem cells enhances the trans‐differentiation to putative germ cells compared to the exogenous treatment of retinoic acid or bone morphogenetic protein 4 signalling molecules
Authors: Yan Guangyao , Fan Yixuan , Li Peizhen , Zhang YanLi , Wang Feng 
Published: July 2014

AbstractThe plasticity of human and murine bone marrow mesenchymal stem cells (BMSCs) has been proven by their ability to trans‐differentiate to multilineage cells, including germ cells. We have investigated ability of goat BMSCs to trans‐differentiate to germ cells with extrinsic (e.g., retinoic acid [RA] and BMP4 signalling molecules) and intrinsic factor expression (e.g., DAZL gene ectopic expression). Having optimized the concentration of RA and BMP4, gBMSCs were treated with RA 1 µM) and BMP4 (25 ng/mL), individually and collectively. Both RA and BMP4 induced OCT4, MVH, DAZL, STELLA, NANOG and C‐KIT expression, but RNF17, PIWIL2, STRA8, and SCP3 were only expressed after RA treatment. In terms of an endogenous factor, a germ cell specific gene, deleted in Azoospermia‐like (DAZL), was overexpressed by plasmid and mRNA techniques. Compared with the RA treated group, DAZL ectopic expression upregulated the transcription and translation of MVH, and SCP3 was also increased at the mRNA level. The mRNA‐based method had more effect on the germ cells gene expression compared to the plasmid method. Ectopic expression of the DAZL gene enhanced trans‐differentiation compared to the RA‐treated group. Knockdown experiments confirmed the pivotal role of DAZL in germ cell differentiation. This study provides further information on the mechanisms underlying the spermatogenesis, which will guide the derivation of post‐meiotic germ cells from adult stem cells in vitro.
p21‐activated kinase 7 is an oncogene in human osteosarcoma
Authors: Han Kun , Zhou Yan , Gan Zhi‐Hua , Qi Wei‐Xiang , Zhang Jian‐Jun , Fen Tao , Meng Wei , Jiang Ling , Shen Zan , Min Da‐Liu 
Published: July 2014

Abstractp21‐activated kinase 7 (PAK7), also named as PAK5, is a member of Rac/Cdc42‐associated Ser/Thr protein kinases. It is overexpressed in some types of cancer such as colorectal and pancreatic cancers. However, the expression status and biological function of PAK7 in osteosarcoma are still ambiguous. To evaluate the expression levels of PAK7 in osteosarcoma tissues and cell lines, immunohistochemistry was used. To investigate the role of PAK7 in cell proliferation, apoptosis and tumorigenicity in vitro and vivo, a recombinant lentivirus expressing PAK7 short hairpin RNA (Lv‐shPAK7) was developed and transfected into Saos‐2 cells. The silencing effect of PAK7 was confirmed by quantitative real‐time PCR (qRT‐PCR) and Western blot technique. PAK7 was overexpressed in osteosarcoma tissue and cell line. By knocking‐down of PAK7, the proliferation and colony formation of Saos‐2 cells were inhibited and apoptosis enhanced significantly. The in vivo tumorigenic ability in xenograft model of Saos‐2 cells was also notably inhibited when PAK7 was knocked down. Our results imply that PAK7 promotes cell proliferation and tumorigenesis and may be an attractive candidate for the therapeutic target of osteosarcoma.
IL‐1β microenvironment promotes proliferation, migration, and invasion of human glioma cells
Authors: Fathima Hurmath K. , Ramaswamy Palaniswamy , Nandakumar Dalavaikodihalli Nanjaiah 
Published: July 2014

AbstractAmong the primary brain tumors, glioblastoma is the most common and severe. Glioblastoma have poor prognosis because of their highly diffusive growth pattern and invasion into surrounding brain tissue. Human glioblastoma cells overexpress interleukin‐1β (IL‐1β) and also the levels of IL‐1β in U87MG glioma cells are significantly higher than in U373, T98G, A172 glioma cell lines. Malignant tumors are characterized by unlimited proliferation, migration and invasion. This study examines the effect of IL‐1β microenvironment on proliferation, migration and invasion in human glioma cell line U87MG that expresses wild‐type p53 protein, and U251MG which expresses mutant p53. Proliferation was investigated by MTT assay, migration by wound‐healing migration assay and invasion by in vitro transwell Matrigel invasion assay. An IL‐1β microenvironment significantly increased migration and invasion of both wild‐type and mutant p53 expressing glioma cells, but significantly increased proliferation only in U87MG glioma cells. These effects were inhibited by IL‐1 receptor antagonist (IL‐1Ra), thus giving evidence that an IL‐1β milieu promotes glioma cell migration, invasion, and proliferation.
Nitrogen‐Doped Pitch‐Based Spherical Active Carbon as a Nonmetal Catalyst for Acetylene Hydrochlorination
Authors: Wang Xugen , Dai Bin , Wang Yang , Yu Feng 
Published: July 2014

AbstractA highly active nitrogen‐doped pitch‐based spherical activated carbon catalyst (PSAC‐N) is synthesized through a nitrogen‐doping treatment and used as a nonmetal catalyst for acetylene hydrochlorination. The conversion of acetylene on PSAC‐N exceeds 68 % and the selectivity of vinyl chloride is over 99 % at a temperature of 250 °C, an acetylene gas hourly space velocity of 120 h−1, and a feed volume ratio V(HCl)/V(C2H2) of 1.15. DFT calculations performed with Gaussian 09 program package reveal that the active site of PSAC‐N has a N‐6v (quaternary nitrogen bonded between two 6‐membered rings) structure. A seven benzene ring unit model is used in the DFT study. In addition, the reason for inactivation for PSAC‐N catalysts is discussed. Of all the adsorption energies obtained, the adsorption capacity of hydrogen chloride on PSAC‐N is the highest, which indicates strong ability for acetylene hydrochlorination. The reaction mechanism is determined, and the reaction energy of N‐6v(7) calculated as 236.2 kJ mol−1.
ZnIn2S4: A Photocatalyst for the Selective Aerobic Oxidation of Amines to Imines under Visible Light
Authors: Ye Lin , Li Zhaohui 
Published: July 2014

AbstractFlowerlike nanospheres of ZnIn2S4 consisting of interweaving nanoflakes were prepared by a rapid microwave‐assisted solvothermal method. The photocatalytic performance of ZnIn2S4 in the aerobic oxidation of amines to imines is for the first time revealed. As‐prepared ZnIn2S4 showed high efficiency for the transformations of various amines into their corresponding imines under visible‐light irradiation by using air as the oxidant. The photocatalytic performance of ZnIn2S4 in the selective oxidation of amines to their corresponding imines is much higher than that of graphitic C3N4 and CdS previously reported. A plausible mechanism involving the oxygenation of amines to form aldehydes, followed by the nucleophilic addition of the amines to afford the final imines is proposed. The use of a cheap, environmentally friendly inorganic semiconductor photocatalyst and solar energy makes this transformation green and sustainable.
Dynamics of the NbCl5‐Catalyzed Cycloaddition of Propylene Oxide and CO2: Assessing the Dual Role of the Nucleophilic Co‐Catalysts
Authors: D'Elia Valerio , Ghani Amylia A. , Monassier Antoine , Sofack‐Kreutzer Julien , Pelletier Jeremie D. A. , Drees Markus , Vummaleti Sai V. C. , Poater Albert , Cavallo Luigi , Cokoja Mirza , Basset Jean‐Marie , Kühn Fritz. E. 
Published: July 2014

AbstractA mechanistic study on the synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO) catalyzed by NbCl5 and organic nucleophiles such as 4‐dimethylaminopyridine (DMAP) or tetra‐n‐butylammonium bromide (NBu4Br) is reported. A combination of in situ spectroscopic techniques and kinetic studies has been used to provide detailed insight into the reaction mechanism, the formation of intermediates, and interactions between the reaction partners. The results of DFT calculations support the experimental observations and allow us to propose a mechanism for this reaction.
Third‐Order Nonlinear Optical Properties of One‐Dimensional Open‐Shell Molecular Aggregates Composed of Phenalenyl Radicals
Authors: Yoneda Kyohei , Nakano Masayoshi , Fukuda Kotaro , Matsui Hiroshi , Takamuku Shota , Hirosaki Yuta , Kubo Takashi , Kamada Kenji , Champagne Benoît 
Published: July 2014

AbstractThe impact of intermolecular interactions on the third‐order nonlinear optical (NLO) properties of open‐shell molecular aggregates has been elucidated by considering one‐dimensional aggregates of π–π stacked phenalenyl radicals with different intermolecular distances and the long‐range corrected spin‐unrestricted density functional theory method. In the phenalenyl dimer, which can be considered as a diradicaloid system, the diradical character strongly depends on the intermolecular distance, and the larger the intermolecular distance is, the larger the diradical character becomes. Then, around the equilibrium stacking distance that corresponds to an intermediate diradical character, its second hyperpolarizability (γ) is maximized and its value per monomer exhibits about a 30‐fold enhancement with respect to the isolated phenalenyl monomer. This suggests that equilibrium is an optimal compromise between localization and delocalization of the radical electron pairs in such pancake bonding. No such effect was observed for the closed‐shell coronene dimer. Moreover, when going from the dimer (diradical) to the tetramer (tetraradical), the γ‐enhancement ratio increases nonlinearly with the aggregate size, whereas switching from the singlet to the highest spin (quintet) state causes a significant reduction of γ. Finally, for the tetramer, another one‐order enhancement of γ is achieved for the dicationic singlet relative to its singlet neutral state. These results demonstrate the key role of intermolecular π–π stacking interactions and charge in open‐shell (supra)molecular systems to achieve enhanced third‐order NLO properties.
Studies on [PtCl2]‐ or [AuCl]‐Catalyzed Cyclization of 1‐(Indol‐2‐yl)‐2,3‐Allenols: The Effects of Water/Steric Hindrance and 1,2‐Migration Selectivity
Authors: Qiu Youai , Fu Chunling , Zhang Xue , Ma Shengming 
Published: July 2014

AbstractThe [PtCl2]‐ or [AuCl]‐catalyzed reaction of 1‐(indol‐2‐yl)‐2,3‐allenols occurred smoothly at room temperature to afford a series of poly‐substituted carbazoles efficiently. Compared with the [PtCl2]‐catalyzed process, the [AuCl]‐catalyzed reaction represents a significant advance in terms of the scope and the selectivity. Selective 1,2‐alkyl or aryl migration of the gold carbene intermediate was observed: compared with the methyl group, the isopropyl, cyclopropyl, cyclobutyl, and cyclohexyl groups migrate exclusively; the cyclopropyl group shifts selectively over the ethyl group; the 1,2‐migration of a non‐methyl linear alkyl is faster than methyl group; the phenyl group migrates exclusively over methyl or ethyl group. DFT calculations show that water makes the elimination of H2O facile requiring a much lower energy and validates the migratory preferences of different alkyl or phenyl groups observed.