bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheological, electrokinetic, and morphological characterization of alginate–bentonite biocomposites
Authors: Benli B. , Boylu F. , Can M. F. , Karakaş F. , Çinku K. , Ersever G. 
Published: April 2011

AbstractWe prepared biocomposite gel dispersions involving sodium alginate (Na‐Alg) and calcium bentonite (Ca‐B) with various solid concentrations and characterized their rheological, electrokinetic, and morphological properties. The flow properties, such as the apparent and plastic viscosities, shear stress, and yield value point, changed with increasing clay dosage. The viscosities of the homogeneous dispersions were represented by the Herschel–Bulkley model. The ζ‐potential results were examined in the light of different characterization methods (X‐ray diffraction, Fourier transform infrared spectroscopy, and atomic force microscopy) to understand the interactions between the Na and Ca ions of the alginate biopolymer and bentonite clay. A plausible structural model for the alginate–bentonite composite gel, known as the egg‐box model, is proposed. The presence of Ca ions in the Ca‐B partially crosslinked Na‐Alg may be regarded as an excellent example of a self‐assembling process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Effect of diblock copolymer surfactant on the microstructure and EM properties of CNT nanocomposites
Authors: Travaglia P. , Nanni F. , Hojati‐Talemi P. , Simon G. P 
Published: April 2011

AbstractCarbon nanotubes (CNTs) were chosen due to their excellent electrical properties. As delivered, CNTs are highly agglomerated, and to exploit their high aspect ratio is then necessary to disagglomerate them as much as possible. A diblock copolymer surfactant was used to aid CNT disagglomeration. Disagglomeration in solvent was assessed by TEM, whereas composite microstructure was observed by scanning electron microscopy. X‐band waveguide measurements were carried out to assess complex permittivity and absorbing performance. On a same weight percent of filler basis, samples produced with the aid of surfactant show higher real permittivity than samples produced without. An equivalent circuit analogy is suggested to explain the results and relates composite microstructure with macroscopic permittivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Incorporating MATLAB® modules in reinforced concrete design instruction
Authors: Urgessa Girum S. 
Published: April 2011

ABSTRACTThe Civil Engineering Department at George Mason University offered a structural design course that combines reinforced concrete and structural steel prior to Fall 2009. With recent re‐designing of course offerings, the course is split into two separate design courses: reinforced concrete design and structural steel design. The new teaching format allows instructors to incorporate additional instruction methods in design classes that supplement traditional teaching. This article discusses the development and implementation of computational MATLAB design modules that are incorporated in the first and second offering of the new reinforced concrete design course. The main objective of the modules is to improve students' computational skills for solving routine design calculations without compromising the theoretical understanding of the subject matter. The graphical user interface driven modules are designed to include program descriptions, user‐friendly field inputs, and a detailed results summary with step‐by‐step design verifications. A classroom survey was conducted on the use of the design modules and results of the survey are presented. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:209–215, 2014; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20547
Substituent Size Effects in Lewis Base Induced Reductions in Organolanthanide Chemistry
Authors: Bojer Daniel , Neumann Beate , Stammler Hans‐Georg , Mitzel Norbert W. 
Published: April 2011

AbstractThe reaction of the tripodal 1,3,5‐trialkyl‐1,3,5‐triazacyclohexanes (L=cyclo‐[N(R)CH2]3, R=Et, iPr, tBu), with [Sm(AlMe4)3] resulted in the formation of divalent samarium complexes of the constitution [{LnSm(AlMe4)2}m] (n, m=1,2) under ethane extrusion. These compounds were characterised by single‐crystal X‐ray diffraction and elemental analyses. Simultaneous occurrence of Lewis base induced reduction and CH‐activation reactions is observed. The ratio of products depends on the bulkiness of the N‐alkyl substituent R. The reaction of [Sm(AlMe4)3] with 1,3,5‐triisopropyl‐1,3,5‐triazacyclohexane (TiPTAC) in benzene afforded the inversion‐symmetric dimer [{(TiPTAC)(η3‐AlMe4)Sm}2(μ2‐AlMe4)2], whereas in toluene the pseudo‐samarocene [(TiPTAC)2Sm(η1‐AlMe4)2] was obtained. The trisaluminate [(TiPTAC)Sm{(μ2‐Me)(Me2Al)}2(μ3‐CH2)2AlMe2)] was found to be the CH‐activation product. In the case of the particular bulky 1,3,5‐tri‐tert‐butyl‐1,3,5‐triazacyclohexane (TtBuTAC), the reaction led to the formation of the dimeric [{(TtBuTAC)(η3‐AlMe4)Sm}2(μ2‐AlMe4)2] even in toluene in comparably high yields. The decrease of the steric demand to ethyl groups in 1,3,5‐triethyl‐1,3,5‐triazacyclohexane (TETAC) afforded the samarocene‐like [(TETAC)2Sm(η1‐AlMe4)2] in lower yields. The resulting divalent samarium compounds are found to be stable with respect to reagents like dinitrogen, conjugated olefins and polycyclic aromatic systems.
Gold‐ and Copper‐Catalyzed Cycloisomerizations towards the Synthesis of Thujopsanone‐Like Compounds
Authors: Fehr Charles , Vuagnoux Magali , Buzas Andrea , Arpagaus Jeremy , Sommer Horst 
Published: April 2011

AbstractIn the search for a new access to thujopsanone related compounds by cycloisomerization reactions of unsaturated propargylic alcohols and acetates, we found several interesting reaction types and demonstrated the complementarity of Au, Pt, and Cu catalysts. Thus, 6‐en‐1‐yn‐3‐ol 10 a underwent clean cyclization/ether formation to 16, in particular using Au catalysts (76–98 %) or a newly prepared CuI‐ triflimidate‐catalyst (94 %). The corresponding acetate 11 a underwent either the cycloisomerization with concomitant [1,2]‐acyl shift (to 12: 78 % using AuCl3) or an unprecedented rearrangement‐cycloaddition leading to 20 (43 % using [(tBuXPhos)AuNTf2]), a strained fused tricyclic ring system containing a [2.2.0] bicyclic subunit.
Design and Characterization of Endosomal‐pH‐Responsive Coiled Coils for Constructing an Artificial Membrane Fusion System
Authors: Kashiwada Ayumi , Tsuboi Mana , Takamura Naohide , Brandenburg Enrico , Matsuda Kiyomi , Koksch Beate 
Published: April 2011

AbstractA weakly acidic pH‐responsive polypeptide is believed to have the potential for an endosome escape function in a polypeptide‐triggered delivery system. For constructing a membrane fusion device with pH‐responsiveness, we have designed novel polypeptides that are capable of forming an α2 coiled coil structure. Circular dichroism spectroscopy reveals that a polypeptide, AP‐LZ(EH5), with a Glu and His salt‐bridge pair at a staggered position in the hydrophobic core forms a stable coiled coil structure only at endosomal pH values (pH 5.0 to 5.5). On the basis of their endosomal‐pH responsiveness, a boronic acid/polypeptide conjugate (BA‐H5‐St) was also designed as a pilot molecule to construct a pH‐responsive, one‐way membrane fusion system with a sugarlike compound (phosphatidylinositol: PI)‐containing liposome as a target. Membrane fusion behavior was characterized by lipid‐mixing, inner‐leaflet lipid‐mixing, and contents‐mixing assays. These studies reveal that membrane fusion is clearly observed when the pH of the experimental system is changed from 7.4 (physiological condition) to 5.0 (endosomal condition).
Cycloheptatrienyl Zirconium Sandwich Complexes with Lewis Basic Phospholyl Ligands (Phosphatrozircenes): Synthesis, Structure, Bonding and Coordination Chemistry
Authors: Glöckner Andreas , Bannenberg Thomas , Büschel Susanne , Daniliuc Constantin G. , Jones Peter G. , Tamm Matthias 
Published: April 2011

AbstractThe transmetalation reaction between [(η7‐C7H7)ZrCl(tmeda)] (1; tmeda=N,N,N′,N′‐tetramethylethylenediamine) and various phospholide anions leads to a new class of mixed sandwich complexes: [(η7‐C7H7)Zr(η5‐C4PMe4)] (2), [(η7‐C7H7)Zr(η5‐C4PH2Me2)] (3) and [(η7‐C7H7)Zr(η5‐C4PPhHMe2)] (4). The presence of Lewis basic phosphorus atoms and Lewis acidic zirconium atoms allows ambiphilic behaviour to be observed, and X‐ray diffraction analysis reveals dimeric arrangements for 2 and 3 with long intermolecular ZrP bonds, whereas 4 remains monomeric in the solid state. DFT calculations indicate that the metal–phosphorus interaction is weak, and accordingly, complexes 2–4 act as monodentate ligands upon reaction with [W(CO)5(thf)]. The resulting complexes [W(CO)5(L)] 5–7 (L=2–4) were studied by IR spectroscopy and compared with the [W(CO)5] complex 9, containing the phosphane‐functionalised trozircene [(η7‐C7H7)Zr(η5‐C5H4PPh2)] (8). They all show a close resemblance to simple phosphanes, such as PMe3, although molecular orbital analysis of 2 reveals that the free electron pair in the phosphatrozircenes is not the HOMO. Four equivalents of 2 can replace 1,4‐cyclooctadiene (COD) in [Ni(cod)2] to form the homoleptic, distorted tetrahedral complex [Ni{2}4] (10).
Generating optimal CUDA sparse matrix–vector product implementations for evolving GPU hardware
Authors: El Zein Ahmed H. , Rendell Alistair P. 
Published: April 2011

SUMMARYThe CUDA model for graphics processing units (GPUs) presents the programmer with a plethora of different programming options. These includes different memory types, different memory access methods and different data types. Identifying which options to use and when is a non‐trivial exercise. This paper explores the effect of these different options on the performance of a routine that evaluates sparse matrix–vector products (SpMV) across three different generations of NVIDIA GPU hardware. A process for analysing performance and selecting the subset of implementations that perform best is proposed. The potential for mapping sparse matrix attributes to optimal CUDA SpMV implementations is discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Isolation and live imaging of enteric progenitors based on Sox10‐Histone2BVenus transgene expression
Authors: Corpening Jennifer C. , Deal Karen K. , Cantrell V. Ashley , Skelton Stephanie B. , Buehler Dennis P. , Southard‐Smith E. Michelle 
Published: April 2011

AbstractTo facilitate dynamic imaging of neural crest (NC) lineages and discrimination of individual cells in the enteric nervous system (ENS) where close juxtaposition often complicates viewing, we generated a mouse BAC transgenic line that drives a Histone2BVenus (H2BVenus) reporter from Sox10 regulatory regions. This strategy does not alter the endogenous Sox10 locus and thus facilitates analysis of normal NC development. Our Sox10‐H2BVenus BAC transgene exhibits temporal, spatial, and cell‐type specific expression that reflects endogenous Sox10 patterns. Individual cells exhibiting nuclear‐localized fluorescence of the H2BVenus reporter are readily visualized in both fixed and living tissue and are amenable to isolation by fluorescence activated cell sorting (FACS). FACS‐isolated H2BVenus+ enteric NC‐derived progenitors (ENPs) exhibit multipotency, readily form neurospheres, self‐renew in vitro and express a variety of stem cell genes. Dynamic live imaging as H2BVenus+ ENPs migrate down the fetal gut reveals cell fragmentation suggesting that apoptosis occurs at a low frequency during normal development of the ENS. Confocal imaging both during population of the fetal intestine and in postnatal gut muscle strips revealed differential expression between individual cells consistent with down‐regulation of the transgene as progression towards non‐glial fates occurs. The expression of the Sox10‐H2BVenus transgene in multiple regions of the peripheral nervous system will facilitate future studies of NC lineage segregation as this tool is expressed in early NC progenitors and maintained in enteric glia. genesis 49:599–618, 2011. © 2011 Wiley‐Liss, Inc.
An in vivo map of bone morphogenetic protein 2 post‐transcriptional repression in the heart
Authors: Kruithof Boudewijn P. T. , Xu Junwang , Fritz David T. , Cabral Carolina S. , Gaussin Vinciane , Rogers Melissa B. 
Published: April 2011

AbstractThe Bmp2 3′untranslated region (UTR) sequence bears a sequence conserved between mammals and fishes that can post‐transcriptionally activate or repress protein synthesis. We developed a map of embryonic cells in the mouse where this potent Bmp2 regulatory sequence functions by using a lacZ reporter transgene with a 3′UTR bearing two loxP sites flanking the ultra‐conserved sequence. Cre‐recombinase‐mediated deletion of the ultra‐conserved sequence caused strong ectopic expression in proepicardium, epicardium and epicardium‐derived cells (EPDC) and in tissues with known epicardial contributions (coronary vessels and valves). Transient transfections of reporters in the epicardial/mesothelial cell (EMC) line confirmed this repression. Ectopic expression of the recombined transgene also occurred in the aorta, outlet septum, posterior cardiac plexus, cardiac and extracardiac nerves and neural ganglia. Bmp2 is dynamically regulated in the developing heart. 3′UTR‐mediated mechanisms that restrain BMP2 synthesis may be relevant to congenital heart and vasculature malformations and to adult diseases involving aberrant BMP2 synthesis. genesis 49:841–850, 2011. © 2011 Wiley‐Periodicals, Inc.
A mouse reporter line to conditionally mark nuclei and cell membranes for in vivo live‐imaging
Authors: Shioi Go , Kiyonari Hiroshi , Abe Takaya , Nakao Kazuki , Fujimori Toshihiko , Jang Chuan‐Wei , Huang Cheng‐Chiu , Akiyama Haruhiko , Behringer Richard R. , Aizawa Shinichi 
Published: April 2011

AbstractLive‐imaging is an essential tool to visualize live cells and monitor their behaviors during development. This technology demands a variety of mouse reporter lines, each uniquely expressing a fluorescent protein. Here, we developed an R26R‐RG reporter mouse line that conditionally and simultaneously expresses mCherry and EGFP in nuclei and plasma membranes, respectively, from the Rosa26 locus. The intensity and resolution of mCherry nuclear localization and EGFP membrane localization were demonstrated to be sufficient for live‐imaging with embryos that express RG (mCherry and EGFP) ubiquitously and specifically in fetal Sertoli cells. The conditional R26R‐RG reporter mouse line should be a useful tool for labeling nuclei and membranes simultaneously in distinct cell populations. genesis 49:570–578, 2011. © 2011 Wiley‐Liss, Inc.
Theoretical Study of Phosphorescence of Iridium Complexes with Fluorine‐Substituted Phenylpyridine Ligands
Authors: Li Xin , Minaev Boris , Ågren Hans , Tian He 
Published: April 2011

AbstractTime‐dependent density functional theory (TD‐DFT) with linear and quadratic response approaches was applied to calculate absorption and luminescence spectra of a number of facial and meridional iridium complexes with fluorine‐substituted phenylpyridine (Fnppy) ligands. The absorption and luminescence spectra were studied to simulate the photophysical properties of electroluminescent devices fabricated on the basis of these iridium complexes used to increase spin–orbit coupling and the triplet‐state blue emission of the corresponding organic light‐emitting diodes (OLEDs). By using the quadratic response technique, the phosphorescence radiative rate constant and lifetime of the studied iridium complexes were calculated through spin–orbit coupling perturbation and compared with the measured data in experiments. A satisfactory agreement between these data permits us to guide improvements in the design of phosphorescence‐based OLEDs by predicting the structure–property relationships through quantum chemical calculations.
Syntheses and Evaluation of Simplified Pretubulysin Analogues
Authors: Burkhart Jens L. , Müller Rolf , Kazmaier Uli 
Published: April 2011

AbstractThe syntheses of new tubulysin analogues are described, in which the central amino acid, tubuvaline, is replaced by the rather simple building blocks phenyltubuvaline and phenoxytubuvaline. These analogues can be obtained in only two to three steps from easily accessible starting materials. Although the new derivatives are less active than the tubulysins, their activities towards U‐2 OS tumor cells are still in the nanomolar range.
Enantioselective Total Synthesis of (+)‐Stachyflin: A Potential Anti‐Influenza A Virus Agent Isolated from a Microorganism
Authors: Sakurai Junji , Kikuchi Takuya , Takahashi Ohgi , Watanabe Kazuhiro , Katoh Tadashi 
Published: April 2011

AbstractA novel and potent hemagglutinin inhibitor, (+)‐stachyflin, was efficiently synthesized in an enantioselective manner starting from the (+)‐5‐methyl‐Wieland–Miescher ketone. The synthetic method features a BF3·Et2O‐induced cascade epoxide‐opening/rearrangement/cyclization reaction tostereoselectively construct the requisite pentacyclic ring system in one step. In order to rationalize the mechanism of the cascade reaction, quantum chemical calculations of the possible intermediary carbocations and transition states in the model synthesis were carried out. An alternative approach to synthesize (+)‐stachyflin by employing a similar cascade reaction was also described.
Micellar electrokinetic chromatography profiles of human high‐density lipoprotein phospholipids
Authors: Chong Chin‐Pong , Lin Ting‐Yu , Chang Chia‐Liang , Yang Ying‐Ling , Tsai Ming‐Hua , Yu Yu‐Shan , Liu Mine‐Yine 
Published: April 2011

AbstractA simple and fast micellar electrokinetic chromatography (MEKC) method was developed to investigate phospholipids isolated from human high‐density lipoproteins (HDL). To optimize the MEKC conditions, several factors including bile salt concentration and organic modifier concentration in the separation buffer as well as temperature have been examined. The optimal separation buffer chosen was a mixture of 50 mM bile salts, 30% v/v 1‐propanol and 10 mM sodium phosphate (pH 8.5). The applied voltage and temperature selected were 25 kV and 40°C, respectively. Meanwhile, high‐salt stacking has been performed for sample pre‐concentration to enhance peak sensitivity. Several factors including organic modifier concentration and salt concentration in the sample matrix as well as sample injection time have been optimized. The optimal sample buffer selected was a mixture of 100 mM NaCl and 20% 1‐propanol, and the optimal sample injection time selected was 32 s under a pressure of 0.5 psi. Several phospholipid standards including lysophosphatidyl choline, phosphatidyl choline (PC), sphingomyelin, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl serine and phosphatidic acid have been studied using the optimal MEKC method. The MEKC profile of the mixed phospholipid standards showed good separation and reproducibility. The linear ranges for PC and sphingomyelin were 0.025–1.2 and 0.025–2.0 mg/mL, respectively. The concentration limits of detection of PC and sphingomyelin were 0.0156 and 0.0199 mg/mL, respectively. Using phosphatidic acid as an internal standard, precision and accuracy have been measured for PC and sphingomyelin. The intraday and interday quantitative analysis showed good results. The new MEKC method has been used to characterize native, in vitro oxidized and glycated human HDL phospholipids within 16 min. At absorbance 200 nm, two similar peaks were observed for native and oxidized HDL phospholipids, but three peaks were observed for glycated HDL phospholipids. Interestingly, at absorbance 234 nm, distinctively different MEKC profiles were observed for the three HDL phospholipids.
Hydroxyethylcellulose‐graft‐poly(2‐(dimethylamino)ethyl methacrylate) as physically adsorbed coating for protein separation by CE
Authors: Cao Fuhu , Luo Zhaofeng , Zhou Dan , Zeng Rongju , Wang Yanmei 
Published: April 2011

AbstractIn this work, a novel graft copolymer, hydroxyethylcellulose‐graft‐poly(2‐(dimethylamino)ethyl methacrylate) (HEC‐g‐PDMAEMA), used as physical coatings of the bare fused‐silica capillaries, was synthesized by using ceric ammonium nitrate initiator in aqueous nitric acid solution. EOF measurement results showed that the synthesized HEC‐g‐PDMAEMA graft copolymer‐coated capillary in this paper could suppress EOF effectively compared to the bare fused‐silica capillary, and efficient separations of basic proteins were also achieved. The electrical charge of the coated capillary wall could be modulated by varying not only the pH of the running buffer, but also the grafting ratio of poly(2‐(dimethylamino)ethyl methacrylate) grafts, which makes possible the analysis of basic and acidic proteins in the same capillary. The effects of poly(2‐(dimethylamino)ethyl methacrylate) grafting ratio in HEC‐g‐PDMAEMA and buffer pH on the separation of basic proteins for capillary electrophoresis were investigated in detail. Furthermore, egg white proteins and milk powder samples were separated by the HEC‐g‐PDMAEMA‐coated capillary. The results demonstrated that the HEC‐g‐PDMAEMA copolymer coatings have great potential in the field of diagnosis and proteomics.
Hydrophobic labeling of amino acids: Transient trapping–capillary/microchip electrophoresis
Authors: Sueyoshi Kenji , Hashiba Kota , Kawai Takayuki , Kitagawa Fumihiko , Otsuka Koji 
Published: April 2011

AbstractTransient trapping (tr‐trapping) was developed as one of the on‐line sample preconcentration techniques to improve a low concentration‐sensitivity in microchip electrophoresis (MCE), providing highly effective preconcentration and separation based on the trap‐and‐release mechanism. However, a poor performance to hydrophilic analytes limited the applicability of tr‐trapping. To overcome this drawback, tr‐trapping was combined with a sample labeling using a hydrophobic reagent in CE. Three commercially available fluorescent dyes, fluorescein isothiocyanate, succinimidyl esters of Alexa Fluor 488 and BODIPY FL‐X, were tested as derivatization reagents to increase the hydrophobicity of amino acids (AAs) that were undetectable due to no fluorescence/UV‐absorbance. As a result, it was confirmed that BODIPY labeling allowed various AAs to be analyzed in tr‐trapping–micellar electrokinetic chromatography (tr‐trapping–MEKC) by the increase in the hydrophobicity. In tr‐trapping–MEKC, both the improvement of the resolution and 106–125‐fold enhancements of the detectability of labeled AAs were achieved relative to the conventional capillary zone electrophoresis. The limit of detection of labeled phenylalanine was improved from 800 to 5 pM by applying tr‐trapping–MEKC. In tr‐trapping–microchip MEKC, furthermore, an 80–160‐fold enhancement of the peak intensity and a baseline separation was also achieved within 30 s. These results clearly demonstrate that the tr‐trapping technique with hydrophobic labeling will make CE/MCE more sensitive for various analytes.
Mass spectrometry detection as an innovative and advantageous tool in ligand exchange capillary electrophoresis
Authors: Giuffrida Alessandro , Contino Annalinda , Maccarrone Giuseppe , Messina Marianna , Cucinotta Vincenzo 
Published: April 2011

AbstractThe copper(II) complex of a modified cyclodextrin, namely 6‐mono‐deoxy‐6‐[4‐(2‐aminoethyl)imidazolyl]‐β‐CD (CDmh), previously synthesized and characterized in our laboratory and already used as chiral selector for ligand exchange capillary electrophoresis (LECE) with optical detection, is investigated here in LECE using electrospray‐mass spectrometry (ESI‐MS) as the detection device. The potential of this hyphenated method is compared with the results previously obtained with optical detection by studying the chiral resolution of tryptophan racemate. Chiral separation conditions compatible with LECE‐ESI‐MS could be achieved based on the figures of merit obtained by LECE‐UV. Interestingly, the values of LOD obtained by LECE‐ESI‐MS were significantly better than those obtained by LECE‐UV and thus, ESI‐MS detection seems to open new perspectives in chiral separations by LECE.