bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards a Practical Development of Light‐Driven Acceptorless Alkane Dehydrogenation
Authors: Chowdhury Abhishek Dutta , Weding Nico , Julis Jennifer , Franke Robert , Jackstell Ralf , Beller Matthias 
Published: May 2014

AbstractThe efficient catalytic dehydrogenation of alkanes to olefins is one of the most investigated reactions in organic synthesis. In the coming years, an increased supply of shorter‐chain alkanes from natural and shale gas will offer new opportunities for inexpensive carbon feedstock through such dehydrogenation processes. Existing methods for alkane dehydrogenation using heterogeneous catalysts require harsh reaction conditions and have a lack of selectivity, whereas homogeneous catalysis methods result in significant waste generation. A strong need exists for atom‐efficient alkane dehydrogenations on a useful scale. Herein, we have developed improved acceptorless catalytic systems under optimal light transmittance conditions using trans‐[Rh(PMe3)2(CO)Cl] as the catalyst with different additives. Unprecedented catalyst turnover numbers are obtained for the dehydrogenation of cyclic and linear (from C4) alkanes and liquid organic hydrogen carriers. These reactions proceed with unique conversion, thereby providing a basis for practical alkane dehydrogenations.
Synthesis of Long‐Sought C66 with Exohedral Stabilization
Authors: Gao Cong‐Li , Li Xiang , Tan Yuan‐Zhi , Wu Xin‐Zhou , Zhang Qianyan , Xie Su‐Yuan , Huang Rong‐Bin 
Published: May 2014

AbstractPreviously reported fused‐pentagon fullerenes stabilized by exohedral derivatization do not share the same cage with those stabilized by endohedral encapsulation. Herein we report the crystallographic identification of #4348C66Cl10, which has the same cage as that of previously reported Sc2@C66. According to the geometrical data of #4348C66Cl10, both strain relief (at the fused pentagons) and local aromaticity (on the remaining sp2‐hybrided carbon framework) contribute to the exohedral stabilization of this long‐sought 66 carbon atom cage.
A Tandem In Situ Peptide Cyclization through Trifluoroacetic Acid Cleavage
Authors: Chandra Koushik , Roy Tapta Kanchan , Shalev Deborah E. , Loyter Abraham , Gilon Chaim , Gerber R. Benny , Friedler Assaf 
Published: May 2014

AbstractWe present a new approach for peptide cyclization during solid phase synthesis under highly acidic conditions. Our approach involves simultaneous in situ deprotection, cyclization and trifluoroacetic acid (TFA) cleavage of the peptide, which is achieved by forming an amide bond between a lysine side chain and a succinic acid linker at the peptide N‐terminus. The reaction proceeds via a highly active succinimide intermediate, which was isolated and characterized. The structure of a model cyclic peptide was solved by NMR spectroscopy. Theoretical calculations support the proposed mechanism of cyclization. Our new methodology is applicable for the formation of macrocycles in solid‐phase synthesis of peptides and organic molecules.
Single‐Particle Tracking and Modulation of Cell Entry Pathways of a Tetrahedral DNA Nanostructure in Live Cells
Authors: Liang Le , Li Jiang , Li Qian , Huang Qing , Shi Jiye , Yan Hao , Fan Chunhai 
Published: May 2014

AbstractDNA is typically impermeable to the plasma membrane due to its polyanionic nature. Interestingly, several different DNA nanostructures can be readily taken up by cells in the absence of transfection agents, which suggests new opportunities for constructing intelligent cargo delivery systems from these biocompatible, nonviral DNA nanocarriers. However, the underlying mechanism of entry of the DNA nanostructures into the cells remains unknown. Herein, we investigated the endocytotic internalization and subsequent transport of tetrahedral DNA nanostructures (TDNs) by mammalian cells through single‐particle tracking. We found that the TDNs were rapidly internalized by a caveolin‐dependent pathway. After endocytosis, the TDNs were transported to the lysosomes in a highly ordered, microtubule‐dependent manner. Although the TDNs retained their structural integrity within cells over long time periods, their localization in the lysosomes precludes their use as effective delivery agents. To modulate the cellular fate of the TDNs, we functionalized them with nuclear localization signals that directed their escape from the lysosomes and entry into the cellular nuclei. This study improves our understanding of the entry into cells and transport pathways of DNA nanostructures, and the results can be used as a basis for designing DNA‐nanostructure‐based drug delivery nanocarriers for targeted therapy.
The Highly Lewis Acidic Dicationic Phosphonium Salt: [(SIMes)PFPh2][B(C6F5)4]2
Authors: Holthausen Michael H. , Mehta Meera , Stephan Douglas W. 
Published: May 2014

AbstractThe dicationic imidazolium‐phosphonium salt [(SIMes)PFPh2][B(C6F5)4]2 has been prepared and shown to exhibit remarkable Lewis acidity in stoichiometric reactions and acting as an effective Lewis acid catalyst for the hydrodefluorination of fluoroalkanes and the hydrosilylation of olefins.
Palladium‐Catalyzed Decarboxylative Cycloaddition of Vinylethylene Carbonates with Formaldehyde: Enantioselective Construction of Tertiary Vinylglycols
Authors: Khan Ajmal , Zheng Renfeng , Kan Yuhe , Ye Jiang , Xing Juxiang , Zhang Yong Jian 
Published: May 2014

AbstractAn efficient method for the enantioselective construction of tertiary vinylglycols through a palladium‐catalyzed asymmetric decarboxylative cycloaddition of vinylethylene carbonates with formaldehyde was developed. By using a palladium complex generated in situ from [Pd2(dba)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the process allows conversion of racemic 4‐substituted 4‐vinyl‐1,3‐dioxolan‐2‐ones into the corresponding 1,3‐dioxolanes, as methylene acetal protected tertiary vinylglycols, in high yields with good to excellent enantioselectivities.
Synthesis, characterization, and properties of a polyhedral oligomeric octadiphenylsulfonylsilsesquioxane
Authors: Li Ziqian , Yang Rongjie 
Published: May 2014

ABSTRACTA novel polyhedral oligomeric octadiphenylsulfonylsilsesquioxane (ODPSS) was synthesized from octaphenylsilsesquioxane and benzenesulfonyl chloride via a Friedel–Crafts reaction with a high yield. ODPSS was identified by Fourier transform infrared spectroscopy, 1H‐NMR, 13C‐NMR, 29Si‐NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI–TOF MS), wide‐angle X‐ray diffraction, and elemental analysis to be a kind of polyhedral oligomeric silsesquioxane of a T8R8 structure. ODPSS exhibited superior thermal stability according to thermogravimetric analysis. Its initial thermal decomposition temperature (Tonset) was at 491°C in air and 515°C in nitrogen. Thermal and mechanical properties of epoxy resin (EP) composites with ODPSS added were studied by differential scanning calorimetry and tensile testing. The results show that the incorporation of ODPSS at a low loading content not only improved the glass‐transition temperature of the EP composites but also enhanced their tensile strength. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40892.
Preparation and characterization of carboxymethyl starch under ultrasound‐microwave synergistic interaction
Authors: Shi Haixin , Yin Yanzhen , Jiao Shufei 
Published: May 2014

ABSTRACTUsing native cassava starch as raw materials, carboxymethyl starch (CMS) was prepared by ethanol solvent method under the ultrasound‐microwave synergistic interaction. And the structure of CMS was characterized employing Fourier transform infrared (FTIR) spectrometer, scanning electron microscopy (SEM), X‐ray diffraction (XRD) and thermogravimetric analyzer. Typically, the optimal synthesis conditions for the preparation process confirmed by orthogonal experiment L18 (61 × 36) were shown as follows: the ultrasonic treatment temperature was fixed to 35°C and two steps alkalization was employed; the ultrasonic time was 40 min before alkalizing and the ultrasonic power was 220 W; the amount of sodium hydroxide was 8.8 g, the microwave alkalization time was 2 min; the amount of monochloroacetic acid was 11.34 g; the amount of 95% (v/v) ethanol was 70 mL; the microwave etherification time was 3 min. The degree of substitution of prepared CMS was 1.089 ± 0.041, which was increased 30.4% compared with the prepared sample without ultrasound‐microwave synergistic treatment. FTIR results showed that the strong COO characteristic absorption peaks of the stretching vibration were observed at 1613 and 1421 cm−1, which proved that the carboxymethylation of cassava starch was occurred. SEM results suggested that there were many cracks and dents on CMS granules; and, XRD results indicated that the carboxymethylation of starch occurred both in amorphous region and crystalline region, the noticeable damage of crystalline region by carboxymethylation was observed. Thermogravimetric analysis (TG) and derivative TG showed that thermal stability of CMS changed better compared with native starch. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40906.
Processing of a multi‐layer polyetheretherketone composite for use in acetabular cup prosthesis
Authors: Abdullah Mohammed Ruslan , Goharian Amirhossein , Abdul Kadir Mohammed Rafiq , Wahit Mat Uzir 
Published: May 2014

ABSTRACTThe hydroxyapatite polyetheretherketone (HAPEEK) as a non‐degradable bioactive polymer composite material with coating of hydroxyapatite (HA) as a bioactive ceramic material can enhance the osteointegration of carbon fiber reinforced polyetheretherketone (CFRPEEK) as a non‐degradable bioinert polymer composite. This study describes the joining process of CFRPEEK and HAPEEK beam components and coating process of HA on the HAPEEK substrate to achieve the multi‐layer PEEK composite for use in the application of acetabular cup prosthesis. The CFRPEEK and HAPEEK components were ultrasonically welded while the HA was plasma sprayed on the HAPEEK substrate. Ultrasonic welding parameters (length and direction of the energy directors at the interface, welding time, and pressure) were investigated by single cantilever beam and lap shear tests to achieve the optimum bonding strength of CFRPEEK and HAPEEK components. Plasma spraying parameters (e.g., surface speed, powder feed, current, primary gas flow, and system voltage) were altered to achieve the good adhesion of HA coating on the HAPEEK substrate, which was evaluated by scratch test. The results showed that the proposed multi‐layer composite was successfully processed by carrying out the ultrasonic welding and plasma spraying coating processes. The outcomes of this study could be used to develop a non‐metal acetabular cup prosthesis using the proposed multi‐layer composition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40915.
Self‐catalyzed silicon‐containing phthalonitrile resins with low melting point, excellent solubility and thermal stability
Authors: Zhang Zongbo , Li Zheng , Zhou Heng , Lin Xiankai , Zhao Tong , Zhang Mingyan , Xu Caihong 
Published: May 2014

ABSTRACTA series of silicon‐containing self‐catalyzed phthalonitrile derivatives (SiPNs) have been successfully synthesized from reaction of 4‐(4‐aminophenoxy)phthalonitrile (APN) with corresponding chlorosilanes. The chemical structures of the SiPNs were confirmed by spectroscopic techniques. The introduction of silicon‐containing unit into the phthalonitrile structure has dramatically decreased the melting point from 143°C for APN to 40–60°C for the new SiPNs, which also exhibit improved solubility and are soluble in many common solvents. Differential scanning calorimetry analysis showed that they possess the self‐catalyzed behavior with the temperature of exothermic peak due to the self‐catalyzed reaction between 255 and 281°C. The cured SiPNs exhibit excellent thermal stability with glass transition temperature above 450°C, the temperature of 5% weight loss in range of 535–570°C under nitrogen, and 543–562°C under air. Their char yields at 1000°C are in the range of 80.2–82.6% in nitrogen, and 10.1–12.5% in air, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40919.
A Hybrid Coumarin–Thiazole Fluorescent Sensor for Selective Detection of Bisulfite Anions in Vivo and in Real Samples
Authors: Peng Meng‐Jiao , Yang Xiao‐Feng , Yin Bing , Guo Yuan , Suzenet Franck , En Da , Li Jin , Li Chang‐Wei , Duan Yu‐Wei 
Published: May 2014

AbstractA hybrid coumarin–thiazole compound was developed as a novel ratiometric and colorimetric sensor for bisulfite anions. Structure identification of the compound was confirmed by 1H NMR, 13C NMR, 1H,1H COSY, heteronuclear single quantum coherence (HSQC), IR, and HRMS spectroscopy. The detection of bisulfite anions was performed through the Michael addition of the bisulfite anion toward the hybrid coumarin–thiazole sensor. The reaction between the sensor and bisulfite anion caused the fluorescence intensity to decrease at 600 nm and to increase at 450 nm and simultaneously yielded a visible color change from purplish red to colorless because the π conjugation between thiazole and coumarin was blocked. The sensor possessed high selectivity and sensitivity for bisulfite with respect to other common anions in aqueous solution. Moreover, the practical value of this sensor was confirmed by its application in the detection of bisulfite anion in human breast adenocarcinoma cells and granulated sugar.
Modeling mechanical signals on the surface of µCT and CAD based rapid prototype scaffold models to predict (early stage) tissue development
Authors: Hendrikson W. J. , van Blitterswijk C. A. , Verdonschot N. , Moroni L. , Rouwkema J. 
Published: May 2014

ABSTRACTIn the field of tissue engineering, mechano‐regulation theories have been applied to help predict tissue development in tissue engineering scaffolds in the past. For this, finite element models (FEMs) were used to predict the distribution of strains within a scaffold. However, the strains reported in these studies are volumetric strains of the material or strains developed in the extracellular matrix occupying the pore space. The initial phase of cell attachment and growth on the biomaterial surface has thus far been neglected. In this study, we present a model that determines the magnitude of biomechanical signals on the biomaterial surface, enabling us to predict cell differentiation stimulus values at this initial stage. Results showed that magnitudes of the 2D strain—termed surface strain—were lower when compared to the 3D volumetric strain or the conventional octahedral shear strain as used in current mechano‐regulation theories. Results of both µCT and CAD derived FEMs from the same scaffold were compared. Strain and fluid shear stress distributions, and subsequently the cell differentiation stimulus, were highly dependent on the pore shape. CAD models were not able to capture the distributions seen in the µCT FEM. The calculated mechanical stimuli could be combined with current mechanobiological models resulting in a tool to predict cell differentiation in the initial phase of tissue engineering. Although experimental data is still necessary to properly link mechanical signals to cell behavior in this specific setting, this model is an important step towards optimizing scaffold architecture and/or stimulation regimes. Biotechnol. Bioeng. 2014;111: 1864–1875. © 2014 Wiley Periodicals, Inc.
Accelerating genome editing in CHO cells using CRISPR Cas9 and CRISPy, a web‐based target finding tool
Authors: Ronda Carlotta , Pedersen Lasse Ebdrup , Hansen Henning Gram , Kallehauge Thomas Beuchert , Betenbaugh Michael J. , Nielsen Alex Toftgaard , Kildegaard Helene Faustrup 
Published: May 2014

ABSTRACTChinese hamster ovary (CHO) cells are widely used in the biopharmaceutical industry as a host for the production of complex pharmaceutical proteins. Thus genome engineering of CHO cells for improved product quality and yield is of great interest. Here, we demonstrate for the first time the efficacy of the CRISPR Cas9 technology in CHO cells by generating site‐specific gene disruptions in COSMC and FUT8, both of which encode proteins involved in glycosylation. The tested single guide RNAs (sgRNAs) created an indel frequency up to 47.3% in COSMC, while an indel frequency up to 99.7% in FUT8 was achieved by applying lectin selection. All eight sgRNAs examined in this study resulted in relatively high indel frequencies, demonstrating that the Cas9 system is a robust and efficient genome‐editing methodology in CHO cells. Deep sequencing revealed that 85% of the indels created by Cas9 resulted in frameshift mutations at the target sites, with a strong preference for single base indels. Finally, we have developed a user‐friendly bioinformatics tool, named “CRISPy” for rapid identification of sgRNA target sequences in the CHO‐K1 genome. The CRISPy tool identified 1,970,449 CRISPR targets divided into 27,553 genes and lists the number of off‐target sites in the genome. In conclusion, the proven functionality of Cas9 to edit CHO genomes combined with our CRISPy database have the potential to accelerate genome editing and synthetic biology efforts in CHO cells. Biotechnol. Bioeng. 2014; 111: 1604–1616. © 2014 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.
Novel design and development of advanced remote electronics experiments
Authors: Tawfik Mohamed , Monteso Santiago , Garcia‐Loro Felix , Sancristobal Elio , Ruiz Elena , Díaz Gabriel , Colmenar Santos Antonio , Peire Juan , Castro Manuel 
Published: May 2014

ABSTRACTThis article reports on the design and development of a new set of remotely controlled electronics experiments oriented to postgraduates and apprentices. Industrial‐related issues are emphasized to allow understanding of the behavior of electronics components. The experiments are fully delivered online with a high level of flexibility. Remote retrieved results are provided. © 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:327–336, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21602
Visual fluid animation via lifting wavelet transform
Authors: Liu Shiguang , Xu Yixin , Noh Junyong , Tong Yiying 
Published: May 2014

ABSTRACTWhile small‐scale fluid details are crucial elements for the creation of visually pleasing fluid animations, their synthesis often requires heavy computation with traditional grid‐based fluid simulation methods. This paper proposes a novel method for enhancing the appearance of small‐scale details through frequency‐domain analysis. Different from previous work, our method detects and improves fluid details in the frequency‐domain via lifting wavelet decomposition. Based on a coarse‐to‐fine mechanism, the lifting wavelet composition first transforms the velocity in a fine grid into the frequency domain. Next, the velocity field is enhanced separately for different frequency bands. A novel velocity fusion method is developed for the enhancement of low‐frequency parts. On the other hand, high‐frequency parts are enhanced using a specially designed vorticity confinement method. Finally, the application of the inverse lifting wavelet transform determines the final velocity field with increased fine details. Our method can generate perceptually interesting fluid details, matching human visual perception theory. The results of various experiments validate the effectiveness and efficiency of our method. Copyright © 2014 John Wiley & Sons, Ltd.
Leishmanicidal Triterpenes from Lantana camara
Authors: Begum Sabira , Ayub Anjum , Qamar Zehra Syeda , Shaheen Siddiqui Bina , Iqbal Choudhary M. , Samreen  
Published: May 2014

AbstractTwo new natural triterpenes, lantaninilic acid and lantoic acid, along with the known triterpenes lantadene A, and oleanolic, ursolic, betulinic, lantanolic, and camaric acid, were obtained from the aerial parts of Lantana camara through bioassay‐guided isolation, monitoring the in vitro antileishmanial activity against promastigotes of Leishmania major. Oleanolic acid (3), ursolic acid (4), lantadene A (5), and lantanilic acid (7) showed significant leishmanicidal activities with IC50 values of 53.0, 12.4, 20.4, and 21.3 μM, respectively. The IC50 value of ursolic acid (4; 12.4 μM) was found to be comparable with that of the standard drugs, pentamidine (IC50 15.0 μM) and amphotericin B (IC50 0.31 μM). The in vitro activities of L. camara and its constituents against promastigotes of Leishmania major are reported here for the first time.
Garcimultiflorone G, a Novel Benzoylphloroglucinol Derivative from Garcinia multiflora with Inhibitory Activity on Neutrophil Pro‐Inflammatory Responses
Authors: Ting Chia‐Wei , Hwang Tsong‐Long , Chen Ih‐Sheng , Cheng Ming‐Jen , Sung Ping‐Jyun , Yen Ming‐Hong , Chen Jih‐Jung 
Published: May 2014

AbstractA novel benzoylphloroglucinol derivative, garcimultiflorone G (1), was isolated from the fruits of Garcinia multiflora. The structure of 1 was determined through extensive 1D‐ and 2D‐NMR, and MS analyses. Garcimultiflorone G (1) showed inhibitory effects against superoxide anion (O$\rm{{_{2}^{{^\cdot} -}}}$) generation and elastase release by human neutrophils in response to formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine/cytochalasin B (fMLP/CB), with IC50 values of 6.97±1.56 and 11.70±1.58 μM, respectively.
Volatile Oils from the Aerial Parts of Eremophila maculata and Their Antimicrobial Activity
Authors: Youssef Fadia S. , Hamoud Razan , Ashour Mohamed L. , Singab Abdel Nasser , Wink Michael 
Published: May 2014

AbstractThe essential oils isolated from the fresh flowers, fresh leaves, and both fresh and air‐dried stems of Eremophila maculata (Scrophulariaceae) were characterized by GC‐FID and GC/MS analyses. Sabinene was the major component in most of the oils, followed by limonene, α‐pinene, benzaldehyde, (Z)‐β‐ocimene, and spathulenol. The leaf and flower essential oils showed antibacterial and antifungal activity against five Gram‐positive and four Gram‐negative bacterial strains, multi‐resistant clinical isolates from patients, i.e., methicillin‐resistant Staphylococcus aureus (MRSA), as well as two yeasts. Minimum inhibitory concentrations (MICs) and minimum microbicidal concentrations (MMCs) were between 0.25 and 4 mg/ml.
In vitro Growth Inhibition by Hypericum Extracts and Isolated Pure Compounds of Paenibacillus larvae, a Lethal Disease Affecting Honeybees Worldwide
Authors: Hernández‐López Javier , Crockett Sara , Kunert Olaf , Hammer Elfe , Schuehly Wolfgang , Bauer Rudolf , Crailsheim Karl , Riessberger‐Gallé Ulrike 
Published: May 2014

AbstractThe in vitro inhibitory potential of 50 extracts from various species of the flowering plant genus Hypericum was investigated using the KirbyBauer disk diffusion susceptibility test against Paenibacillus larvae, a spore‐forming, Gram‐positive bacterial pathogen that causes American foulbrood (AFB), a lethal disease affecting honeybee brood worldwide. Of the tested extracts, 14 were identified as highly active against P. larvae as compared to the activity of the positive control, indicating the presence of highly potent antibacterial compounds in the extracts. Examination of these extracts using TLC and HPLC/MS analyses revealed the presence of acylphloroglucinol and filicinic‐acid derivatives. Six pure compounds isolated from these extracts, viz., hyperforin (1), uliginosin B (2), uliginosin A (3), 7‐epiclusianone (4), albaspidin AA (5), and drummondin E (6), displayed strong antibacterial activity against the vegetative form of P. larvae (MIC ranging from 0.168–220 μM). Incubation of P. larvae spores with the lipophilic extract of Hypericum perforatum and its main acylphloroglucinol constituent 1 led to the observation of significantly fewer colony forming units as compared to the negative control, indicating that the acylphloroglucinol scaffold represents an interesting lead structure for the development of new AFB control agents.