bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organocatalytic Diels–Alder Reaction of 2‐Vinylindoles with Methyleneindolinones: An Efficient Approach to Functionalized Carbazolespirooxindoles
Authors: Huang Lin‐Jie , Weng Jiang , Wang Sheng , Lu Gui 
Published: March 2015

AbstractAn unprecedented asymmetric Diels–Alder reaction of 2‐vinylindoles with methyleneindolinones has been disclosed. Under bifunctional organocatalysis by cinchona‐derived squaramide catalyst, a series of diversely functionalized carbazolespirooxindole derivatives bearing three contiguous stereocenters are rapidly constructed under mild conditions (48–90% yields, up to >20:1 dr and 99% ee).magnified image
Phosphaannulation of Aryl‐ and Benzylphosphonic Acids with Unactivated Alkenes via Palladium‐Catalyzed CH Activation/Oxidative Cyclization Reaction
Authors: Jeon Woo Hyung , Son Jeong‐Yu , Kim Sun‐Eung , Lee Phil Ho 
Published: March 2015

AbstractAn efficient phosphaannulation via palladium(II)‐catalyzed CH activation/oxidative cyclization by the 6‐endo mode is reported for the synthesis of 3‐substituted phosphaisocoumarins from the reaction of arylphosphonic acids with unactivated alkenes under aerobic conditions. Also, α,α‐disubstituted benzylphosphonic acids were phosphaannulated with unactivated alkenes, producing phosphaisochromanones having (Z)‐alkylidenyl groups via anti‐phosphoryloxypalladation by the 6‐exo mode.magnified image
The Lithiation Reactivity and Selectivity of Differentially Branched Alkyldiphenylphosphine Oxides – A Simple and Versatile Approach to ortho‐Functionalized Arylphosphine Oxides
Authors: Mahamulkar Shraddha G. , Císařová Ivana , Jahn Ullrich 
Published: March 2015

AbstractAlkyldiphenylphosphine oxides typically undergo α‐deprotonation with alkyllithium reagents. Here, the lithiation of differentially branched alkyldiphenylphosphine oxides was investigated and a diverse, but predictable reactivity was found. γ‐Branched derivatives undergo selective directed ortho‐metalation (DoM) using butyllithium and TMEDA as an additive. With decreasing degree of γ‐branching α‐lithiation becomes predominant. The ortho‐phosphinoyllithium intermediates are subject to functionalization and CC bond forming reactions, thus providing a convenient approach to new phosphine oxides and phosphine‐borane complexes, which have a good potential for an approach to new ligands for catalysis.magnified image
Enantioselective Construction of Cyclic Indolyl α‐Amino Esters via a Friedel–Crafts Alkylation Reaction
Authors: Wu Liang , Liu Ren‐Rong , Zhang Guoqi , Wang Dan‐Jie , Wu Hao , Gao Jianrong , Jia Yi‐Xia 
Published: March 2015

AbstractAn enantioselective Friedel–Crafts alkylation reaction of indoles with cyclic N‐sulfonyl ketimino esters was developed. Under the optimized conditions using a chiral copper(II) triflate‐bisoxazoline complex as the catalyst, a range of N‐sulfonyl ketimino ester derivatives and indoles reacted smoothly to afford indole‐containing chiral cyclic α‐amino esters bearing tetrasubstituted α‐stereogenic centers [3‐ethoxycarbonyl‐3‐(3‐indolyl)‐2,3‐dihydrobenzo[d]isothiazole 1,1‐dioxides] in excellent yields and with high enantioselectivities (up to 99% ee). Pyrrole and N,N‐dimethylaniline were also investigated as aromatic substrates to afford the corresponding products with good results. An asymmetric induction model was then proposed on the basis of the observed absolute configuration of the product 3‐ethoxycarbonyl‐3‐(5‐bromo‐3‐indolyl)‐2,3‐dihydrobenzo[d]isothiazole 1,1‐dioxide. Synthetic transformations to convert the products into cyclic chiral N‐sulfonamido alcohols and the deprotection of the sulfonamides were performed. This study provides an efficient approach to chiral α‐tetrasubstituted indolic α‐amino acids as potential building blocks for peptides and biologically active molecules.magnified image
N‐Heterocyclic Carbene‐Catalyzed Umpolung Formal [3+3] Cycloaddition of Enals with Isatogens: Access to Fused Indolin‐3‐ones with a Tetrasubstituted Carbon Stereocenter
Authors: Xu Junyu , Hu Shihe , Lu Yingyan , Dong Ying , Tang Weifang , Lu Tao , Du Ding 
Published: March 2015

AbstractA novel synthetic method to access fused indolin‐3‐ones with a tetrasubstituted carbon stereocenter has been developed via NHC‐catalyzed umpolung formal [3+3] cycloaddtion of enals with isatogens. This methodology could be also applied for the quick construction of the 6‐5‐5 tricyclic pyrrolo[1,2‐a]indole skeleton which is frequently found as a core structure of many indole alkaloids.magnified image
Supported Catalysis in Continuous‐Flow Microreactors
Authors: Munirathinam Rajesh , Huskens Jurriaan , Verboom Willem 
Published: March 2015

AbstractThis review surveys the recent developments to perform heterogeneous catalysis in continuous‐flow microreactors. Three different types, namely, (i) packed‐bed, (ii) monolithic, and (iii) wall‐coated approaches are discussed to implement various kinds of catalysts in a microreactor. In addition, the applications of these supported catalysts to perform a variety of organic reactions are described. Furthermore, advantages of catalytic microreactors over classical batch reactors on one or more aspects of the reaction, such as rate, conversion, selectivity, and enantioselectivity are presented.magnified image
Formal N‐Acylation Reaction of Azaaromatics with Acylzirconocene Chloride Complexes and 1,1,1,3,3,3‐Hexafluoro‐2‐propanol
Authors: Saito Akio , Uematsu Yuki , Sudo Kohei , Hanzawa Yuji 
Published: March 2015

AbstractIn the presence of 1,1,1,3,3,3‐hexafluoro‐2‐propanol (1,1,1,3,3,3‐hexafluoroisopropyl alcohol, HFIP), isoquinolines react with acylzirconocene chlorides to give N‐acyl adducts with incorporation of a proton at the C‐1 position. The present procedure could be applied to the reaction of quinolines. These reactions provide us with an alternative method for the Reissert‐type reduction reactions of azaaromatics with N‐acylating reagents and reducing reagents.magnified image
Metal‐Free [2+2+1] Annulation of Alkynes, Nitriles and Nitrogen Atoms from Iminoiodanes for Synthesis of Highly Substituted Imidazoles
Authors: Saito Akio , Kambara Yui , Yagyu Takuma , Noguchi Keiichi , Yoshimura Akira , Zhdankin Viktor V. 
Published: March 2015

AbstractBoron trifluoride nitrile complexes promote oxidative [2+2+1] annulations of alkynes, nitriles and N‐atoms from iminoiodanes to give the corresponding 2,4‐disubstituted and 2,4,5‐trisubstituted N‐tosylimidazoles in moderate to good yields with high regioselectivities.magnified image
Synthese von Kohlenstoffnanostrukturen durch ionothermale Karbonisierung von gewöhnlichen Lösungsmitteln und Lösungen
Authors: Chang Yuanqin , Antonietti Markus , Fellinger Tim‐Patrick 
Published: March 2015

AbstractEine Kombination aus Ionothermalsynthese und Heißinjektionstechnik führte zu aus Lösungsmitteln erzeugten neuartigen Kohlenstoffnanostrukturen. Bei kontrollierter Zugabe von gewöhnlichen Lösungsmitteln zu heißer Zinkchloridschmelze entstanden sphärische, schichtartige oder verzweigt‐nanofaserige Nanopartikel mit erstaunlich hoher Kohlenstoffeffizienz. Die Verwendung Heteroatom‐haltiger Lösungsmittel hatte die Herstellung von Kohlen mit Dotierungsgraden von bis zu 14 Gew.‐% Stickstoff und 13 Gew.‐% Schwefel zur Folge. Hohe Oberflächen und große Porenvolumina der Lösungsmittelkohlen von >1666 m2 g−1 und 2.80 cm3 g−1 sowie CO2‐Absorptionskapazitäten von 4.13 mmol g−1 bei 273 K und 1 bar konnten erhalten werden. Die neuartige Methode ließ sich nicht nur auf reine Kohlen anwenden, sondern wurde zudem auf die Herstellung von Nanokompositmaterialien aus Kohlenstoff und anorganischen Verbindungen ausgeweitet. ZnS@C, Ni@C und Co@C wurden erfolgreich mit der “kinderleichten” Methode hergestellt. Das Ni@C‐Nanokomposit eignet sich zur elektrokatalytischen Wasserspaltung, vergleichbar zu kommerziellen Edelmetallkatalysatoren.
Polymer crystallization rate challenges: The art of chemistry and processing
Authors: Andjelić Saša , Scogna Robert C. 
Published: March 2015

ABSTRACTThe intention of this study is to discuss scientific advances toward one very important challenge in the polymer processing industry: How does one increase the crystallization rate of slow‐to‐crystallize polymeric materials, thereby facilitating processing and enabling peak product performance? In the medical device field, where both government‐controlled regulatory entities and medical professionals closely scrutinize the biocompatibility of added crystallization rate enhancers, achieving these twin goals has always been challenging. Herein, we present a review of various chemical and physical approaches used to tune the crystallization rate of semicrystalline polymers, with a strong emphasis on two novel approaches recently discovered and developed in our laboratories. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42066.
Synthesis of well‐defined amphiphilic block copolymers via AGET ATRP used for hydrophilic modification of PVDF membrane
Authors: Sun Haixiang , Wang Tiantian , Zhou Yingying , Li Peng , Kong Ying 
Published: March 2015

ABSTRACTA well‐defined amphiphilic block copolymer consisting of a hydrophobic block poly(methyl methacrylate) (PMMA) and a hydrophilic block poly[N,N–2‐(dimethylamino) ethyl methacrylate] (PDMAEMA) was synthesized by activator generated by the electron transfer for atom transfer radical polymerization method (AGET ATRP). Kinetics study revealed a linear increase in the graph concentration of PMMA‐b‐PDMAEMA with the reaction time, indicating that the polymer chain growth was consistent with a controlled process. The gel permeation chromatography results indicated that the block copolymer had a narrow molecular weight distribution (Mw/Mn = 1.42) under the optimal reaction conditions. Then, poly(vinylidene fluoride) (PVDF)/PMMA‐b‐PDMAEMA blend membranes were prepared via the standard immersion precipitation phase inversion process, using the block copolymer as additive to improve the hydrophilicity of the PVDF membrane. The presence and dispersion of PMMA‐b‐PDMAEMA clearly affected the morphology and improved the hydrophilicity of the as‐synthesized blend membranes as compared to the pristine PVDF membranes. By incorporating 15 wt % of the block copolymer, the water contact angle of the resulting blend membranes decreased from pure PVDF membrane 98° to 76°. The blend membranes showed good stability in the 20 d pure‐water experiment. The bovine serum albumin (BSA) absorption experiment revealed a substantial antifouling property of the blend membranes in comparison with the pristine PVDF membrane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42080.
A review of the developments of characteristics of PEI derivatives for gene delivery applications
Authors: Taranejoo Shahrouz , Liu Jun , Verma Paul , Hourigan Kerry 
Published: March 2015

ABSTRACTRedox‐active stimuli have gained a great deal of interest as an indicating factor for designing bioresponsive matrices in gene delivery. Hence, a wide range of gene carriers has been designed incorporating the redox‐stimuli characteristics. The most important type of gene carriers is the class of redox responsive polymers. Among them, disulfide incorporated redox‐responsive polyethyleneimine (PEI) and its derivatives, as a result of their outstanding DNA entrapping characteristics and their intrinsic endosomolytic activity, have attracted considerable attention in recent studies. The review presents the main developments of the characteristics of PEI derivatives and their applications in gene delivery. It is found that despite the uniquely stated characteristics, the noncleavable structure of conventional PEI (high molecular weight PEI: 25k), which makes it a nondegradable material, as well as the frequent inclusion of positively charged amino groups, which reduces its blood circulation period, render conventional PEI a very toxic material for gene‐delivery applications. The extremely high cellular toxicity of conventional PEI has restricted its administration for real in‐vivo physiological media. Recent studies have shown that employing low molecular weight PEI cross‐linked by disulfide linkages (SS‐PEI) and assembling low molecular weight disulfide linkages PEI (LMW SS‐PEI) with bio‐detachable anionic groups were two successful approaches for increasing bioavailability of the PEI‐based gene carriers, while keeping outstanding cellular transfection. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42096.
Modification of luminescence spectra of CaF2: Eu2+
Authors: Singh Vartika S. , Joshi C. P. , Moharil S. V. , Muthal P. L. , Dhopte S. M. 
Published: March 2015

AbstractCaF2:Eu2+ is a well known phosphor having efficient excitation in the near ultraviolet (NUV) range. Phosphors with NUV excitation are required in newly emerging applications such as photoluminescence liquid crystal displays (PLLCD), solid‐state lighting (SSL), and down‐conversion for solar cells. However, emission of CaF2:Eu2+ is around 424 nm. Eye sensitivity drops considerably at these wavelengths. It is thus not useful for display applications for which emission in one of the primary colours (blue – 450 nm, green – 540 nm or red – 610 nm) is required. Efforts were made to modify the Photoluminescence (PL) spectra of CaF2:Eu2+ to meet these requirements using co‐dopants. A Ca0.49Sr0.50Eu0.01F2 phosphor showing better colour coordinates and having an emission maximum around 440 nm was discovered during these studies. Copyright © 2015 John Wiley & Sons, Ltd.
Study on the interaction of a cyanine dye with human serum transferrin
Authors: Zhang Xiu‐feng , Chen Lei , Yang Qian‐fan , Li Qian , Sun Xiao‐ran , Chen Hong‐bo , Yang Guang , Tang Ya‐lin 
Published: March 2015

AbstractComplexation between the primary carrier of ligands in blood plasma, human serum transferrin (Tf), and a cyanine dye, 3,3′‐di(3‐sulfopropyl)‐4,5,4′,5′‐dibenzo‐9‐phenyl‐thiacarbocyanine‐triethylam monium salt (PTC) was investigated using fluorescence spectra, UV/Vis absorption spectra, synchronous fluorescence spectra, circular dichroism (CD) and molecular dynamic docking. The experimental results demonstrate that the formation of PTC–Tf complex is stabilized by van der Waal's interactions and hydrogen bonds, and the binding constants were found to be 8.55 × 106, 8.19 × 106 and 1.75 × 104 M−1. Moreover, fluorescence experiments prove that the operational mechanism for the fluorescence quenching is static quenching and non‐radiative energy transfer. Structural investigation of the PTC–Tf complexes via synchronous fluorescence spectra and CD showed that the structure of Tf became more stable with a major increase in the α‐helix content and increased polarity around the tryptophan residues after PTC binding. In addition, molecular modeling highlights the residues located in the N‐lobe, which retain high affinity for PTC. The mode of action of the PTC–Tf complex is illustrated by these results, and may provide an effective pathway for the transport and targeted delivery of antitumor agents. Copyright © 2015 John Wiley & Sons, Ltd.
Study on interactions of aminoglycoside antibiotics with calf thymus DNA and determination of calf thymus DNA via the resonance Rayleigh scattering technique
Authors: Qiao Man , Li Chunyan , Shi Ying , Liu Shaopu , Liu Zhongfang , Hu Xiaoli 
Published: March 2015

AbstractA simple and sensitive resonance Rayleigh scattering (RRS) spectra method was developed for the determination of calf thymus DNA (ctDNA). The enhanced RRS signals were based on the interactions between ctDNA and aminoglycoside antibiotics (AGs) including kanamycin (KANA), tobramycin (TOB), gentamicin (GEN) and neomycin (NEO) in a weakly acidic medium (pH 3.3–5.7). Parameters influencing the method were investigated. Under optimum conditions, increments in the scattering intensity (∆I) were directly proportional to the concentration of ctDNA over certain ranges. The detection limit ranged from 12.2 to 16.9 ng/mL. Spectroscopic methods, including RRS spectra, absorption spectra and circular dichroism (CD) spectroscopy, coupled with thermo‐denaturation experiments were used to study the interactions, indicating that the interaction between AGs with ctDNA was electrostatic binding mode. Copyright © 2015 John Wiley & Sons, Ltd.
Heat shock protein 27 overexpression in CHO cells modulates apoptosis pathways and delays activation of caspases to improve recombinant monoclonal antibody titre in fed‐batch bioreactors
Authors: Tan Janice G.L. , Lee Yih Yean , Wang Tianhua , Yap Miranda G. S. , Tan Tin Wee , Ng Say Kong 
Published: March 2015

AbstractCHO cells are major production hosts for recombinant biologics including the rapidly expanding recombinant monoclonal antibodies (mAbs). Heat shock protein 27 (HSP27) expression was observed to be down‐regulated towards the late‐exponential and stationary phase of CHO fed‐batch bioreactor cultures, whereas HSP27 was found to be highly expressed in human pathological cells and reported to have anti‐apoptotic functions. These phenotypes suggest that overexpression of HSP27 is a potential cell line engineering strategy for improving robustness of CHO cells. In this work, HSP27 was stably overexpressed in CHO cells producing recombinant mAb and the effects of HSP27 on cell growth, volumetric production titer and product quality were assessed. Concomitantly, HSP27 anti‐apoptosis functions in CHO cells were investigated. Stably transfected clones cultured in fed‐batch bioreactors displayed 2.2‐fold higher peak viable cell density, delayed loss of culture viability by two days and 2.3‐fold increase in mAb titer without affecting the N‐glycosylation profile, as compared to clones stably transfected with the vector backbone. Co‐immunoprecipitation studies revealed HSP27 interactions with Akt, pro‐caspase 3 and Daxx and caspase activity profiling showed delayed increase in caspase 2, 3, 8 and 9 activities. These results suggest that HSP27 modulates apoptosis signaling pathways and delays caspase activities to improve performance of CHO fed‐batch bioreactor cultures.
Doing that thing that scientists do: A discovery‐driven module on protein purification and characterization for the undergraduate biochemistry laboratory classroom
Authors: Garrett Teresa A. , Osmundson Joseph , Isaacson Marisa , Herrera Jennifer 
Published: March 2015

AbstractIn traditional introductory biochemistry laboratory classes students learn techniques for protein purification and analysis by following provided, established, step‐by‐step procedures. Students are exposed to a variety of biochemical techniques but are often not developing procedures or collecting new, original data. In this laboratory module, students develop research skills through work on an original research project and gain confidence in their ability to design and execute an experiment while faculty can enhance their scholarly pursuits through the acquisition of original data in the classroom laboratory. Students are prepared for a 6–8 week discovery‐driven project on the purification of the Escherichia coli cytidylate kinase (CMP kinase) through in class problems and other laboratory exercises on bioinformatics and protein structure analysis. After a minimal amount of guidance on how to perform the CMP kinase in vitro enzyme assay, SDS‐PAGE, and the basics of protein purification, students, working in groups of three to four, develop a protein purification protocol based on the scientific literature and investigate some aspect of CMP kinase that interests them. Through this process, students learn how to implement a new but perhaps previously worked out procedure to answer their research question. In addition, they learn the importance of keeping a clear and thorough laboratory notebook and how to interpret their data and use that data to inform the next set of experiments. Following this module, students had increased confidence in their ability to do basic biochemistry techniques and reported that the “self‐directed” nature of this lab increased their engagement in the project. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(3):145–153, 2015.
Green Practices and Organizational Design as Sources of Strategic Flexibility and Performance
Authors: Perez‐Valls Miguel , Cespedes‐Lorente Jose , Moreno‐Garcia Juan 
Published: March 2015

AbstractGreen competences are dynamic capabilities based on practices (green practices), routines and structures that can be used to detect opportunities, make the most of them and use them to transform organizations. With this in mind, we explore the relationships between environmental management, organizational performance, and organizational processes and practices. We identify three key constructs related to green competences: (1) hybrid structures, (2) environmental best practices and (3) strategic flexibility, a key variable connecting structural design and green practices to organizational performance. We propose that the implementation of specific organizational structures characterized by the inclusion of market‐driven control practices within hierarchies (internal hybrids) could enhance firms' environmental responsiveness and deployment of green best practices. In addition, we suggest that green practices and structures are positively related to the development of strategic flexibility, driving above‐average returns in dynamic environments. To test these hypotheses, we use data from the European aviation industry. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment
Dual Soft‐Template System Based on Colloidal Chemistry for the Synthesis of Hollow Mesoporous Silica Nanoparticles
Authors: Li Yunqi , Bastakoti Bishnu Prasad , Imura Masataka , Tang Jing , Aldalbahi Ali , Torad Nagy L. , Yamauchi Yusuke 
Published: March 2015

AbstractA new dual soft‐template system comprising the asymmetric triblock copolymer poly(styrene‐b‐2‐vinyl pyridine‐b‐ethylene oxide) (PS‐b‐P2VP‐b‐PEO) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to synthesize hollow mesoporous silica (HMS) nanoparticles with a center void of around 17 nm. The stable PS‐b‐P2VP‐b‐PEO polymeric micelle serves as a template to form the hollow interior, while the CTAB surfactant serves as a template to form mesopores in the shells. The P2VP blocks on the polymeric micelles can interact with positively charged CTA+ ions via negatively charged hydrolyzed silica species. Thus, dual soft‐templates clearly have different roles for the preparation of the HMS nanoparticles. Interestingly, the thicknesses of the mesoporous shell are tunable by varying the amounts of TEOS and CTAB. This study provides new insight on the preparation of mesoporous materials based on colloidal chemistry.
Ein neuer Ansatz zur Charakterisierung der Flüssigphasenadsorption an Aktivkohlen
Authors: Treese Julian , Pasel Christoph , Luckas Michael , Bathen Dieter 
Published: March 2015

AbstractAktivkohlen sind industriell häufig eingesetzte Adsorbentien. Die Charakterisierung ihrer Oberflächeneigenschaften bereitet jedoch aufgrund der Vielzahl an Rohstoffen und Herstellungsvarianten Probleme. Hier wird eine Modellvorstellung zur Beschreibung der Oberfläche hergeleitet, die auf der Kenntnis der wesentlichen chemischen Wechselwirkungen auf Aktivkohleoberflächen basiert, die bereits erforscht wurden. An verschiedenen Aktivkohlen werden Adsorptionsisothermen ausgesuchter Probemoleküle vermessen und mit den Daten überprüft, inwiefern das Modell zur Bewertung der Oberflächenchemie von Aktivkohlen geeignet ist.
Stabilitätsanalyse mehrphasiger Strömungen in Mikrokanälen
Authors: Antweiler Nicolai , Munera Parra Alejandro A. , Agar David W. 
Published: March 2015

AbstractDie Durchführung von mehrphasigen Reaktionen und Extraktionen in Mikrokanälen ermöglicht eine Intensivierung chemischer Prozesse. Eine Übertragung dieser Technologie in den industriellen Maßstab erfordert Strategien zur Skalierung ohne Maßstabsänderung. In dieser Arbeit findet eine Stabilitätsanalyse mehrphasiger Strömungen in Mikrokanälen statt. Es wird eine Gas/Flüssig‐Strömung modelliert und die Druckverlustdynamik in Abhängigkeit von Strömungs‐ und Stoffeigenschaften analysiert. Für mögliche Strategien zur Parallelisierung machen diese Ergebnisse auf die Notwendigkeit eines aktiven Regelkonzeptes aufmerksam.