bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic Cell–Derived Exosomes Need To Activate Both T and B Cells To Induce Antitumor Immunity
Authors: Näslund Tanja I. , Gehrmann Ulf , Qazi Khaleda R. , Karlsson Mikael C. I. , Gabrielsson Susanne 
Published: February 2013

Abstract
Exosomes are secreted membrane nanovesicles of endosomal origin and are considered potential cancer vaccine vectors. Phase I clinical trials have been successfully conducted with tumor peptide–loaded exosomes derived from dendritic cells (dexosomes), and a phase II clinical trial is ongoing. However, much is still unknown regarding the in vivo role of dexosomes and whether their immunogenicity can be enhanced. We previously reported that dexosomes induce CD4+ T cell responses in a B cell–dependent manner, suggesting that immunization with dexosomes carrying only T cell peptides induce suboptimal immune responses. In this study, we show that CD8+ T cell responses were induced in vivo when mice were immunized with protein-loaded, but not peptide-loaded, dexosomes. We also show that the cytotoxic T cell response was totally dependent on CD4+ T cells and, interestingly, also on B cells. Mice deficient in complement activation and Ag shuttling by B cells have lower responses to protein-loaded dexosomes, showing involvement of these B cell–mediated mechanisms. Finally, protein-loaded dexosomes were superior in protecting against tumor growth. In conclusion, proper activation of CD4+ T and B cells needs to be considered when designing cancer vaccines to ensure full potential of the treatment.
A Mechanistic Study of Wetting Superhydrophobic Porous 3D Meshes
Authors: Yohe Stefan T. , Freedman Jonathan D. , Falde Eric J. , Colson Yolonda L. , Grinstaff Mark W. 
Published: February 2013

AbstractSuperhydrophobic, porous, 3D materials composed of poly(ϵ‐caprolactone) (PCL) and the hydrophobic polymer dopant poly(glycerol monostearate‐co‐ϵ‐caprolactone) (PGC‐C18) are fabricated using the electrospinning technique. These 3D materials are distinct from 2D superhydrophobic surfaces, with maintenance of air at the surface as well as within the bulk of the material. These superhydrophobic materials float in water, and when held underwater and pressed, an air bubble is released and will rise to the surface. By changing the PGC‐C18 doping concentration in the meshes and/or the fiber size from the micro‐ to nanoscale, the long‐term stability of the entrapped air layer is controlled. The rate of water infiltration into the meshes, and the resulting displacement of the entrapped air, is quantitatively measured using X‐ray computed tomography. The properties of the meshes are further probed using surfactants and solvents of different surface tensions. Finally, the application of hydraulic pressure is used to quantify the breakthrough pressure to wet the meshes. The tools for fabrication and analysis of these superhydrophobic materials as well as the ability to control the robustness of the entrapped air layer are highly desirable for a number of existing and emerging applications.
Properties of electrospun poly(vinyl alcohol) hydrogel nanofibers crosslinked with 1,2,3,4‐butanetetracarboxylic acid
Authors: Çay Ahmet , Mohsen Miraftab  
Published: February 2013

AbstractABSTRACT: Electrospun nanofibrous hydrogel membranes have been gaining significant importance due to the combination of unique physical properties of nanofibers and biocompatibility of hydrogels. Thus, they are considered as potential candidates for medical textile applications. This study deals with electrospinning of poly(vinyl alcohol) (PVA) hydrogel nanofibrous membranes. The chemical crosslinking of PVA with proportionate quantities of 1,2,3,4 butanetetracarboxylic acid (BTCA) was undertaken to form hydrogel structures. Cross‐linked membranes were characterized by scanning electron microscopy, FT‐IR and thermogravimetric analysis, water swelling, and durability tests. FT‐IR analysis demonstrated the formation of ester linkages between PVA and BTCA and thermogravimetric analysis showed that crosslinking improved the thermal stability of the nanofibrous structure. Furthermore, the results indicated that crosslinking with BTCA improved water stability of PVA membranes and the nanofibrous structure was preserved after water treatment. It is envisaged that use of BTCA as a cross‐linker to form hydrogel nanofibers could be a practical and a promising method for medical textile applications, especially for wound dressings given its nontoxicity and immiscibility with polymer solutions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Solvent‐resistant nanofiltration membranes based on multilayered polyelectrolytes deposited on silicon composite
Authors: Chen Dongju 
Published: February 2013

AbstractAlternating deposition of oppositely charged polyelectrolyte complexes (PECs) on inorganic–organic composite membranes can efficiently overcome the drawback of microcracks induced by inorganic particles. Different bilayers of Poly (diallyldimethylammonium, chloride)/sulfonated poly(ether ether ketone) (PDDA/SPEEK) were first deposited on the charged silicon composite with hydrolyzed polyacrylonitrile (PAN‐H) support and evaluated for solvent resistant nanofiltration membranes (SRNF) application. The morphology of the membranes was studied in detail via SEM and AFM. Because of Donnan exclusion, the multilayered PEC silicon composite membranes showed very high retentions up to 99% for negatively charged solutes (Rose Bengal (RB), 1017 Da) in the pressure driven filtration of isopropanol (IPA) solutions. For the first time, PEC‐based silicon composite membranes were also applied in the filtration of organic solvents, where they were found to combine a remarkable stability in polar solvents with high fluxes and retentions. Compared with silicon composite membranes, the introduction of multilayered PDDA/SPEEK can efficiently improve the membrane performance and overcome the drawback induced by inorganic fillers. PEC‐based silicon composite membranes thus show excellent prospective use in SRNF. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Copper(II) Triflate Promoted Multicomponent Catalytic Clubbing of Piperazinyl‐Thiazoloquinolines and Thiazolocoumarins as Antimicrobials
Authors: Patel Rahul V. , Patel Jigar K. , Nile Shivraj H. , Park Se Won 
Published: February 2013

AbstractStep economical, multicomponent construction of two series based on quinoline and coumarin ring systems was carried out. Annulation towards the 2‐piperazinylthiazole system was established in satisfactory yields, using copper(II) triflate. These multicomponent reaction products were examined for their potential inhibitory effect against two Gram‐positive bacteria (Staphylococcus aureus and Bacillus cereus), three Gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and two fungal species (Aspergillus niger and Candida albicans). In vitro pharmacological screening data demonstrated that the majority of the compounds were found to possess a significant broad‐spectrum antimicrobial (25–50 µg/mL of MIC) potential and the results were comparable to control drugs. The structural assignments of final products were done on the basis of IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis. The structure–activity relationship (SAR) was explored to facilitate further development of this class of compounds.
Investigation on the co‐luminescence effect of europium (III)–lanthanum(III)–dopamine–sodium dodecylbenzene sulfonate system and its application
Authors: Si Hailin , Zhao Fang , Cai Huan 
Published: February 2013

ABSTRACTA novel luminescence, enhancement phenomenon in the europium(III)–dopamine–sodium dodecylbenzene sulfonate system was observed when lanthanum(III) was added. Based on this, a sensitive co‐luminescence method was established for the determination of dopamine. The luminescence signal for the europium (III)–lanthanum(III)–dopamine–sodium dodecylbenzene sulfonate system was monitored at λex = 300 nm, λem =618 nm and pH 8.3. Under optimized conditions, the enhanced luminescence signal responded linearly to the concentration of dopamine in the range 1.0 × 10–10–5.0 × 10–7 mol/L with a correlation coefficient of 0.9993 (n = 11). The detection limit (3σ) was 2.7 × 10–11 mol/L and the relative standard deviation for 11 parallel measurements of 3.0 × 10–8 mol/L dopamine was 1.9%. The presented method was successfully applied for the estimation of dopamine in samples of pharmaceutical preparations, human serum and urine. The possible luminescence enhancement mechanism of the system is discussed briefly. Copyright © 2013 John Wiley & Sons, Ltd.
Sonochemical synthesis of Ag nanoclusters: electrogenerated chemiluminescence determination of dopamine
Authors: Liu Tao , Zhang Lichun , Song Hongjie , Wang Zhonghui , Lv Yi 
Published: February 2013

ABSTRACTWe report a facile one‐pot sonochemical approach to preparing highly water‐soluble Ag nanoclusters (NCs) using bovine serum albumin as a stabilizing agent and reducing agent in aqueous solution. Intensive electrogenerated chemiluminescence (ECL) was observed from the as‐prepared Ag (NCs) and successfully applied for the ECL detection of dopamine with high sensitivity and a wide detection range. A possible ECL mechanism is proposed for the preparation of Ag NCs. With this method, the dopamine concentration was determined in the range of 8.3 × 10–9 to 8.3 × 10–7 mol/L without the obvious interference of uric acid, ascorbic acid and some other neurotransmitters, such as serotonin, epinephrine and norepinephrine, and the detection limit was 9.2 × 10–10 mol/L at a signal/noise ratio of 3. Copyright © 2013 John Wiley & Sons, Ltd.
Convergent mechanisms in pluripotent stem cells and cancer: Implications for stem cell engineering
Authors: Mooney Bridget M. , Raof Nurazhani Abdul , Li Yan , Xie Yubing 
Published: February 2013

AbstractStem cells and cancer cells share certain characteristics, including the capacity to self‐renew, differentiatie, and undergo epithelial‐to‐mesenchymal transition (EMT). The mechanisms underlying tumorigenesis retain similarities with processes in normal stem cell development. Comprehensive analysis and comparison of cancer cell and stem cell development will advance the study of cancer progression, enabling development of effective strategies for cancer treatment. In this review article, we first examine the convergence of outcome, cellular communication, and signaling pathways active in pluripotent stem cells and cancer cells. Next, we detail how stem cell engineering is able to mimic in vivo microenvironments. These efforts can help better identify stem cell‐cancer cell interactions, elucidated dysregulated pluripotent signaling pathways occurring in cancer, revealed new factors that restrict tumorigenesis and metastasis potential, and reprogrammed cancer cells to a less aggressive phenotype. The potential of stem cell engineering to enhance cancer research is tremendous and may lead to alternative therapeutic options for aggressive cancers.
Lipophilic Extracts from Needles and Defoliated Twigs of Pinus pumila from Two Different Populations
Authors: Shpatov Alexander V. , Popov Sergey A. , Salnikova Olga I. , Shmidt Emma N. , Kang Suk Woo , Kim Sang Min , Um Byung Hun 
Published: February 2013

AbstractHexane extracts of needles and defoliated twigs of Pinus pumila (Pall.) Regel from two distant populations, located in the southwest and the east (i.e., Lake Baikal region and Sakhalin Island) of the species distribution range were studied by GC/MS analysis. Composition and retention indices of major components were determined. A drastic composition divergence for the extracts of P. pumila needles and defoliated twigs, depending on growth location, was established. Needle extracts from the eastern population sample contained mainly labdane‐type acids (anticopalic acid derivatives), whereas the predominant components of needle extracts from the other population sample were abietane‐type acids (abietic, neoabietic acids) and isopimarane‐type diterpenoids (sandaracopimaric acid, sandaracopimaradien‐3β‐ol). The main components of defoliated twig extracts from Sakhalin Island population sample were abietane‐type acids and cembrane‐type diterpenoids, while content of these compounds in the extracts of the southwestern marginal population sample was remarkably lower.
Molecular Spoked Wheels: Synthesis and Self‐Assembly Studies on Rigid Nanoscale 2D Objects
Authors: Aggarwal A. Vikas , Jester Stefan‐S. , Taheri Sara Mehdizadeh , Förster Stephan , Höger Sigurd 
Published: February 2013

AbstractWe present the efficient synthesis of a new molecular spoked‐wheel structure (MSW‐3). Two derivatives with diameters of approximately 4 nm have been prepared. By highlighting the importance of pseudo‐high‐dilution conditions during cyclization, we were able to access the compounds on a several hundred milligram scale. In addition to the standard characterization (NMR spectroscopy, MS), we describe a detailed investigation of the optical properties of the fluorescent MSWs by comparison with appropriate model chromophores. Furthermore, a comprehensive study of the structure in solution by means of light‐ and X‐ray scattering experiments has been conducted. Scanning tunneling microscopy (STM) revealed the two‐dimensional organization of the molecules on highly oriented pyrolytic graphite and emphasized the spoked‐wheel structure. The diameter of these molecules measured by small‐angle X‐ray scattering is in very good agreement with that obtained from STM and matches the results of molecular modeling. This confirms the rigidifying effect of the spokes, which results in highly shape‐persistent nanometer‐sized oblate organic compounds.
Escherichia coli β‐Galactosidase Inhibitors through Modifications at the Aglyconic Moiety: Experimental Evidence of Conformational Distortion in the Molecular Recognition Process
Authors: Calle Luis , Roldós Virginia , Cañada F. Javier , Uhrig María Laura , Cagnoni Alejandro J. , Manzano Verónica E. , Varela Oscar , Jiménez‐Barbero Jesus 
Published: February 2013

AbstractHerein, we describe the use of thioglycosides as glycosidase inhibitors by employing novel modifications at the reducing end of these glycomimetics. The inhibitors display a basic galactopyranosyl unit (1→4)‐bonded to a 3‐deoxy‐4‐thiopentopyranose moiety. The molecular basis of the observed inhibition has been studied by using a combination of NMR spectroscopy and molecular modeling techniques. It is demonstrated that these molecules are not recognized by Escherichia coli β‐galactosidase in their ground‐state conformation, with a conformational selection process taking place. In fact, the observed conformational distortion depends on the chemical nature of the compounds and results from the rotation around the glycosidic linkage (variation of Φ or Ψ) or from the deformation of the six‐membered ring of the pentopyranose. The bound conformations of the ligand are adapted in the enzymatic pocket with a variety of hydrogen‐bond, van der Waals, and stacking interactions.
A Total Synthesis of Spirastrellolide A Methyl Ester
Authors: Arlt Alexander , Benson Stefan , Schulthoff Saskia , Gabor Barbara , Fürstner Alois 
Published: February 2013

AbstractA concise total synthesis of spirastrellolide A methyl ester (1 a, R1=Me) as the parent compound of a series of highly cytotoxic marine macrolides is disclosed, which exploits and expands the flexibility of a synthesis plan previously developed by our group en route to the sister compound spirastrellolide F methyl ester (6 a, R1=Me). Key to success was the masking of the signature Δ15,16‐bond of 1 a as a C16‐carbonyl group until after the stereogenic center at C24 had been properly set by a highly selective hydrogenation of the C24 exo‐methylene precursor 66. Conformational control over the macrocyclic frame allowed the proper stereochemical course to be dialed into this reduction process. The elaboration of the C16 ketone to the C15–C16 double bond was accomplished by a chemoselective alkenyl triflate formation followed by a palladium‐catalyzed hydride delivery. The role of the ketone at C16 as a strategic design element is also evident up‐stream of the key intermediate 66, the assembly of which hinged upon the addition of the polyfunctionalized dithiane 37 to the similarly elaborate aldehyde fragment 46. Other crucial steps of the total synthesis were an alkyl‐Suzuki coupling and a Yamaguchi lactonization that allowed the Northern and the Southern sector of the target to be stitched together and the macrocyclic perimeter to be forged. The lateral chain comprising the remote C46 stereocenter was finally attached to the core region by a modified Julia–Kocienski olefination. The preparation of the individual building blocks led to some methodological spin‐offs, amongst which the improved procedure for the N–O‐bond cleavage of isoxazolines by zero‐valent molybdenum and the ozonolysis of a double bond in the presence of other oxidation‐prone functionality are most noteworthy. Preliminary biological data suggest that the entire carbon framework, that is the macrocyclic core plus the lateral chain, might be necessary for high cytotoxicity.
Hierarchical Structures Based on Functionalized Magnetic Cores and Layered Double‐Hydroxide Shells: Concept, Controlled Synthesis, and Applications
Authors: Shao Mingfei , Wei Min , Evans David G. , Duan Xue 
Published: February 2013

AbstractThe combination of magnetic particles and layered double hydroxide (LDHs) materials leads to the formation of hierarchical composites that can take full advantages of each component; this is an effective approach for achieving multifunctional materials with intriguing properties. This Concept article summarizes several important strategies for the fabrication of magnetic‐core/LDH‐shell hierarchical nanocomposites, including direct coprecipitation, layer‐by‐layer assembly, and in situ growth methods. The obtained nanocomposites exhibit excellent performance as multifunctional materials for promising applications in targeted drug delivery, efficient separation, and catalysis. The fabrication and application of magnetic‐core/LDH‐shell nanocomposite materials represent a new direction in the development of LDH‐based multifunctional materials, which will contribute to the progress of chemistry and material science.
Reaction Engineering Investigations of the Partial Oxidation of o‐Xylene in the Explosion Regime – Microfixed Bed versus Catalyst Coating
Authors: Lange Thomas , Heinrich Sebastian , Liebner Christian , Hieronymus Hartmut , Klemm Elias 
Published: February 2013

AbstractThe selective gas phase oxidation of o‐xylene was investigated inside of the explosion regime using a microstructured reactor. The V2O5/TiO2 catalyst was used as microfixed bed and as catalyst coating. There were no significant losses of the selectivity to phthalic anhydride with feed compositions up to 7 vol % o‐xylene observable. Above 7 vol % the selectivity decreased due to total oxidation, especially for the microfixed bed, which was probably caused by a hotspot.
Nuclear Flux Densities during a Model Pericyclic Reaction with Energies Well Above and Below the Potential Barrier
Authors: Bredtmann Timm , Kono Hirohiko , Manz Jörn , Nakamura Kosuke , Stemmle Christian 
Published: February 2013

AbstractPericyclic reactions with energies E well above the potential energy barrier B (case E>B) proceed with quantum nuclear flux densities 〈j〉 which are essentially proportional to the nuclear densities ρ in the femtosecond time domain. This corresponds to the definition of classical (cl) mechanics, jcl=υclρcl, with almost constant velocity vcl. For the other case E<B, however, that is, in the domain of coherent tunneling, we discover the opposite trend, that is, 〈j〉 has maximum value close to the barrier where ρ is a minimum (in fact where ρ is close to zero). The general conclusion is that quantum mechanical nuclear flux densities may be at variance from traditional expectations based on classical trajectories. This prediction calls for experimental demonstration. The counter‐intuitive proof‐of‐principle is demonstrated for a simple, one‐dimensional model of the Cope rearrangement of semibullvalene.
Crossing Over into the Future
Authors: Vashi Preeti 
Published: February 2013

AbstractEurJIC is proud to present a bumper issue on Spin‐Crossover Complexes. Our Guest Editors, Keith Murray, Hiroki Oshio and José Antonio Real, have worked hard to put together a fantastic issue. With a valuable personal account of the field by Philipp Gütlich and inspiring papers by leading experts, you will not be disappointed.
Comparative study of olive oil quality from Chemlali Sfax versus Arbequina cultivated in Tunisia
Authors: Chtourou Mohamed , Gargouri Boutheina , Jaber Hazem , Abdelhedi Ridha , Bouaziz Mohamed 
Published: February 2013

AbstractThe effects of the geographical region on the behavior of the Arbequina olive cultivar (cv) cultivated in the south of Tunisia (in the arid zone of Sfax) was compared to an autochthonous cultivar (Chemlali Sfax). Various olive parameters were analyzed, such as ripening index, pulp/stone ratio, oil contents, and sensory profiles. Most of the quality indices and fatty acid composition showed significant variations among olive cultivars. Arbequina cv is characterized by high oil yield with a less total phenols and pigments content than Chemlali Sfax cv. Cielab spectrophotometer coordinate L*, b*, and a* values show a great difference in olive oil colors. In spite of their low oleic acid contents, autochthonous cultivar presented a higher induction time (6.82 and 2.68 h for Chemlali and Arbequina, respectively) and high contents of phenolic compounds (158.28 and 110.27 mg/kg for Chemlali Sfax and Arbequina, respectively). The most important compounds identified were oleuropein aglycon (45.50 mg/kg), hydroxytyrosol (3.68 mg/kg), 1‐acetoxypinoresinol (6.23 mg/kg) in Chemlali Sfax oil and hydroxytyrosol glucoside (25.15 mg/kg), tyrosol (12.51 mg/kg), and oleuropein aglycon (30.60 mg/kg) in Arbequina oil. Chemlali Sfax also possessed a very bitter taste, whereas the Arbequina had a sweet taste amongst its attributes. The principal component analysis of the results indicated that the geographical region has significantly affected the olive oil quality.
Stereoselective Synthesis of α‐Glycosyl Azides by TMSOTf‐Mediated Ring Opening of 1,6‐Anhydro Sugars
Authors: Lepage Mathieu L. , Bodlenner Anne , Compain Philippe 
Published: February 2013

AbstractAccess to α‐glycosyl azides in modest to high diastereoselectivity by way of TMSN3 ring‐opening of 1,6‐anhydro sugars mediated by TMSOTf is reported. The reaction tolerates a wide variety of functional groups including alcohol, alkyne, azide and ester groups. The efficient synthesis of a pseudopentasaccharide in five steps from commercially available levoglucosan by way of a “click‐click” approach is presented to highlight the interest of the TMSN3 ring‐opening reaction.
1,5,7‐Triazabicyclo[4.4.0]dec‐1‐ene‐Mediated Acetylene Dicarboxylation and Alkyne Carboxylation Using Carbon Dioxide
Authors: Wang Xi , Lim Yu Na , Lee Chan , Jang Hye‐Young , Lee Bun Yeoul 
Published: February 2013

AbstractDirect carboxylation of acetylene with CO2was carried out in the presence of 1,5,7‐triazabicyclo[4.4.0]dec‐1‐ene (TBD); subsequent reduction of dicarboxylated acetylene produces commercially valuable succinate salts. This metal‐free carboxylation has potential economic and environmental impact by utilizing non‐petroleum feedstocks (acetylene) and CO2and by producing valuable chemical feed stocks.