bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal Organic Frameworks as Solid Catalysts in Condensation Reactions of Carbonyl Groups
Authors: Dhakshinamoorthy Amarajothi , Opanasenko Maksym , Čejka Jiří , Garcia Hermenegildo 
Published: January 2013

AbstractThis review summarizes the use of metal organic frameworks (MOFs) as solid catalysts for condensation reactions. After an introductory section, in which condensation reactions are generally presented, a list of the MOFs employed as condensation catalyst is given. The main part of the present review is organized according to the use of MOFs as solid acids, solid bases or as bi‐functional solids containing both acid and basic sites. Throughout the review, the emphasis has been made on discussing the stability of the MOFs, their reusability and in providing a comparison of the performance of MOFs with respect to other homogeneous and heterogeneous catalysts. Finally, we summarize the current state‐of‐the‐art and provide our view on future trends and developments in this field.
Enantioselective Mukaiyama–Michael Reaction of Silyl Enol Ethers to 2‐Enoylpyridine N‐Oxides Catalyzed by Copper‐ Bis(oxazoline) Complex
Authors: George Jimil , Reddy Basi V. Subba 
Published: January 2013

AbstractA catalytic enantioselective Mukaiyama–Michael reaction of 2‐enoylpyridine N‐oxides has been developed using a simple bis(oxazoline)‐copper complex. A variety of silyl enol ethers undergo smooth Michael addition with 2‐enoylpyridine N‐oxides to furnish the corresponding Michael adducts in high yields with high enantioselectivities (up to 97% ee).
Copper‐Catalyzed Tandem CC/CO Bond‐Forming Reactions of ortho‐Halo‐β‐chlorostyrenes with Ketones: Synthesis of 4‐Trifluoromethylbenzoxepines
Authors: Sun Lei‐Lei , Hu Bo‐Lun , Tang Ri‐Yuan , Deng Chen‐Liang , Zhang Xing‐Guo 
Published: January 2013

AbstractA copper‐catalyzed cyclization reaction of trifluoromethyl‐containing ortho‐halo‐β‐chlorostyrenes with ketones has been developed. Using a combination of copper(I) bromide, 2,2,6,6‐tetramethylheptane‐3,5‐dione and sodium tert‐butoxide, a variety of 4‐trifluoromethylbenzoxepines was prepared in moderate to good yields by the tandem α‐alkenylation of ketones with subsequent O‐arylation.
Biomimetic Direct Aldol Reaction of Pyruvate Esters with Chiral Aldehydes
Authors: El‐Sepelgy Osama , Mlynarski Jacek 
Published: January 2013

AbstractDirect aldol reactions of pyruvate esters with sugar aldehydes is efficiently promoted by dinuclear metal complexes or chiral Cinchona alkaloid organocatalysts. Application of sterically hindered aryl esters enables the to‐date problematic aldol reaction of pyruvate donors with syn‐ or anti‐selectivity en route to the short and efficient synthesis of 3‐deoxy‐2‐ulosonic acids.
A boy with partial trisomy of chromosome 3q24–q28 from paternal balanced insertion and multiple congenital anomalies
Authors: Zhu Haiyan , Hu Yali , Zhu Ruifang , Yang Ying , Zhu Xiangyu , Wang Wanjun 
Published: January 2013

AbstractAlthough many patients with duplication 3q syndrome have been described reports on duplication derivatives from an insertion are rare in the previous literature. Here we describe the genotype and phenotype of a 32‐month‐old boy with a partial trisomy of 3q24–q28. We carefully mapped the aberration with SNP‐array analysis, and found a duplication region of 44 Mb. By conventional cytogenetic techniques including fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY) analysis, the patient was found to have inherited a derivative chromosome 6 from his father, which was contained a direct insertion from 3q24–28. The main clinical features of the patient included severe mental retardation, postnatal developmental delay, ventricular septal defect (VSD), and craniofacial anomalies including cleft palate, frontal bossing, hypertelorism, and a broad nasal bridge. The symptoms partially overlap with previously reported patients with duplication in the same region. Prenatal diagnosis for the fetus of this family was performed based on the results of genetic tests and ultrasonic evaluation. © 2013 Wiley Periodicals, Inc.
Epilepsy in Mowat–Wilson syndrome: Delineation of the electroclinical phenotype
Authors: Cordelli Duccio Maria , Garavelli Livia , Savasta Salvatore , Guerra Azzurra , Pellicciari Alessandro , Giordano Lucio , Bonetti Silvia , Cecconi Ilaria , Wischmeijer Anita , Seri Marco , Rosato Simonetta , Gelmini Chiara , Della Giustina Elvio , Ferrari Anna Rita , Zanotta Nicoletta , Epifanio Roberta , Grioni Daniele , Malbora Baris , Mammi Isabella , Mari Francesca , Buoni Sabrina , Mostardini Rosa , Grosso Salvatore , Pantaleoni Chiara , Doz Morena , Poch‐Olivé Maria Luisa , Rivieri Francesca , Sorge Giovanni , Simonte Graziella , Licata Francesca , Tarani Luigi , Terazzi Emanuela , Mazzanti Laura , Cerruti Mainardi Paola , Boni Antonella , Faravelli Francesca , Grasso Marina , Bianchi Paolo , Zollino Marcella , Franzoni Emilio 
Published: January 2013

AbstractMowat–Wilson syndrome (MWS) is a genetic disease caused by heterozygous mutations or deletions of the ZEB2 gene and is characterized by distinctive facial features, epilepsy, moderate to severe intellectual disability, corpus callosum abnormalities and other congenital malformations. Epilepsy is considered a main manifestation of the syndrome, with a prevalence of about 70–75%. In order to delineate the electroclinical phenotype of epilepsy in MWS, we investigated epilepsy onset and evolution, including seizure types, EEG features, and response to anti‐epileptic therapies in 22 patients with genetically confirmed MWS. Onset of seizures occurred at a median age of 14.5 months (range: 1–108 months). The main seizure types were focal and atypical absence seizures. In all patients the first seizure was a focal seizure, often precipitated by fever. The semiology was variable, including hypomotor, versive, or focal clonic manifestations; frequency ranged from daily to sporadic. Focal seizures were more frequent during drowsiness and sleep. In 13 patients, atypical absence seizures appeared later in the course of the disease, usually after the age of 4 years. Epilepsy was usually quite difficult to treat: seizure freedom was achieved in nine out of the 20 treated patients. At epilepsy onset, the EEGs were normal or showed only mild slowing of background activity. During follow‐up, irregular, diffuse frontally dominant and occasionally asymmetric spike and waves discharges were seen in most patients. Sleep markedly activated these abnormalities, resulting in continuous or near‐to‐continuous spike and wave activity during slow wave sleep. Slowing of background activity and poverty of physiological sleep features were seen in most patients. Our data suggest that a distinct electroclinical phenotype, characterized by focal and atypical absence seizures, often preceded by febrile seizures, and age‐dependent EEG changes, can be recognized in most patients with MWS. © 2013 Wiley Periodicals, Inc.
Rhodamine‐labeled Sensor Bead as a Colorimetric and Fluorometric Dual Assay for Hg2+Ions in Water
Authors: Ghosh Kumaresh , Sarkar Tanmay , Majumdar Anupam 
Published: January 2013

AbstractRhodamine‐based receptor1recognizes Hg2+and Cu2+ions in aqueous CH3CN, but when immobilized onto Merrifield resin to give bead2, this sensor system selectively detects Hg2+ions over a series of other metal cations in water. The detection can be performed colorimetrically and fluorimetrically. The ensemble of2–Hg2+can also distinguishdl‐homocysteine fromL‐cysteine in water by both analytical methods.
A blinded randomized controlled trial evaluating the efficacy of chitosan gel on ostial stenosis following endoscopic sinus surgery
Authors: Ngoc Ha Thanh , Valentine Rowan , Moratti Stephen , Robinson Simon , Hanton Lyall , Wormald Peter‐John 
Published: January 2013

BackgroundStenosis of sinus ostia following endoscopic sinus surgery (ESS) is the most common reason for revision surgery. Chitosan‐dextran (CD) gel has been shown to be an effective hemostatic agent; however, its effects on ostial stenosis are unknown. This study aims to quantify the effect of CD gel on circumferential scarring following ESS.MethodsA prospective, blinded, randomized, controlled trial was conducted in 26 patients undergoing ESS. Measurements of neo‐ostia were taken using a standard‐sized measuring probe. CD gel was applied unilaterally, while contralateral sides received no gel. Ostial diameters were measured by a blinded observer at 2, 8, and 12 weeks postoperation. Sinus ostial areas calculated as a proportion of the original were compared for each ostium at each time point.ResultsIntraoperative ostial areas were comparable for CD gel and control sides (38 mm2 vs 39 mm2, 131 mm2 vs 120 mm2, and 203 mm2 vs 193 mm2, in frontal, sphenoid, and maxillary ostia, respectively; p > 0.05). CD gel significantly improved sinus ostial patency. The largest difference was seen when ostial areas at 12 weeks were compared with their corresponding baseline areas (66% vs 31% frontal, p < 0.001; 85% vs 47% sphenoid, p < 0.001; and 74% vs 54% maxillary ostia, p = 0.002). The difference between raw ostial areas reached statistical significance in sphenoid (p < 0.001) and maxillary (p = 0.01), but not in frontal ostia (p > 0.05) at 12 weeks.ConclusionCD gel produced significantly less stenosis of all neo‐ostia following ESS and may reduce the necessity for revision surgery in patients with chronic rhinosinusitis.
Melamine polyphosphate/silicon‐modified phenolic resin flame retardant glass fiber reinforced polyamide‐6
Authors: Xu Yi , Liu Yuan , Wang Qi 
Published: January 2013

AbstractThe halogen‐free flame retardance of glass fiber reinforced polyamide‐6 (PA6) is an everlastingly challenge due to well‐known wick effect. In this research, a novel system composed of a nitrogen–phosphorous flame retardant, melamine polyphosphate combined with a macromolecular charring agent, silicon‐modified phenolic resin (SPR), was employed to flame‐retard glass fiber reinforced PA6. It exhibited obvious synergistic effect between the two components at a proper ratio range. The flame retardance of the composites can be remarkably improved due to the increased amount and improved thermal stability of the produced char. The flame resistance tests indicated that the synergism system with an optimized ratio achieved V0 (1.6 mm) rating of UL94, 25.2% of Limited Oxygen Index, and only 338.2 W/g of the heat release peak rate. The corresponding synergistic mechanisms were investigated by the characterizations including the thermal gravimetric analysis, carbonation test, and the char morphology observation. It confirmed that the introduced SPR could accelerate the carbonation of PA6 resin, which was in favor of the construction of denser and more continuous charring structure. In addition, the flame retardant materials also indicated the acceptable mechanical properties, showing the advantages in the overall performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of UV‐cured hybrid coatings by triethoxysilane‐modified dimethacrylate based on bisphenol‐s epoxy
Authors: Li Chunguang , Cheng Jue , Yang Feng , Chang Wenkai , Nie Jun 
Published: January 2013

AbstractNovel hybrid oligomers based on a UV‐curable bisphenol‐S epoxy dimethacrylate (DBSMA) were synthetized. DBSMA was modified with various amount of (3‐isocyanatopropyl)triethoxysilane coupling agent. The modification degree of the hybrid oligomer was varied from 0 to70 wt %. The photopolymerization kinetics was monitored by a real‐time infrared spectroscopy. The conversion and rate of hybrid coatings increased with the increase in modification degree. UV‐curable, hard, and transparent organic–inorganic hybrid coatings were prepared. They were performed by the analyses of various properties such as surface and mechanical properties. Results from the mechanical measurements showed that the properties of hybrid coatings improved with the increase in modification degree. The thermal behavior of coatings was also investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Improving water solubility of poly(acrylic acid‐co‐styrene) copolymers by adding styrene sulfonic acid as a termonomer
Authors: Akyildiz Halil I. , Michielsen Stephen 
Published: January 2013

AbstractAcrylic acid is often used to make water‐soluble polymers while styrene is often modified to add special functions to polymers. However, when styrene and acrylic acid are copolymerized, the resulting polymer is much less water soluble. To regain water solubility, the effect of styrene sulfonic acid on solubility of poly(acrylic acid‐co‐styrene) copolymers was investigated. Even though acrylic acid polymers are known for their water solubility, the presence of styrene units within acrylic acid copolymers reduces the solubility of the copolymer substantially at the natural pH of the solutions. By adding styrene sulfonic acid as a termonomer, polymers that are water soluble at the natural pH of the polymerization could be obtained. The solubility of the polymer after removal of the solvent and by redissolving at different concentrations and pH levels is also reported. Solubility increases at higher pH especially with low styrene concentration in the copolymer. It was found that incorporation of as little as 5 mol % of styrene into poly(acrylic acid) reduced the aqueous solubility to less than 0.5 g dL−1 at pH 7. Upon adding 7 mol % styrene sulfonic acid as a termonomer, the water solubility increased to 5 g dL−1 at pH 7. At higher levels of styrene, more styrene sulfonic acid was needed, especially at low pH. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Composites based on renewable materials: Polyurethane‐type matrices from forest byproduct/vegetable oil and reinforced with lignocellulosic fibers
Authors: Ramires Elaine C. , de Oliveira Fernando , Frollini Elisabete 
Published: January 2013

AbstractThe use of products and byproducts from the agro‐industry and forest biorefinery is essential for the development of value‐added and low environmental‐impact materials. In this study, polyurethanes were prepared using sodium lignosulfonate (NaLS) and castor oil (CO) as reagents and were used to prepare composites reinforced with lignocellulosic fibers, namely, curaua and coir fibers (30 wt %, 3 cm length, and randomly oriented). The SEM images of fractured surfaces of the composites revealed excellent adhesion at the fiber/matrix interface of both coir and curaua composites, which probably resulted from the favorable interactions between polar groups, as well as amid low polarity domains that are present in both the matrix and the reinforcements. The composites exhibited different impact/flexural and strength/flexural moduli (NaLS/CO/Curaua = 465 Jm−1/44 MPa/2 GPa; NaLS/CO/Coir = 180 Jm−1/25 MPa/1 GPa). The higher tensile strength/aspect ratio of the curaua fibers (485 MPa/259) compared with that of the coir fibers (120 MPa/130) most likely contributes to the enhanced performance of its composite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and self‐assembly of amphiphilic star‐block copolymers consisting of polyethylene and poly(ethylene glycol) segments
Authors: Liu Ran , Li Zhi Yun , Wang Wan Juan , Yuan Dan , Meng Chun Feng , Wu Qing , Zhu Fang Ming 
Published: January 2013

AbstractWe report on the synthesis and self‐assembly in water of well‐defined amphiphilic star‐block copolymers with a linear crystalline polyethylene (PE) segment and two or three poly(ethylene glycol) (PEG) segments as the building blocks. Initially, alkynyl‐terminated PE (PE‐) is synthesized via esterification of pentynoic acid with hydroxyl‐terminated PE, which is prepared using chain shuttling ethylene polymerization with 2,6‐bis[1‐(2,6‐dimethylphenyl) imino ethyl] pyridine iron (II) dichloride/methylaluminoxane/diethyl zinc and subsequent in situ oxidation with oxygen. Then diazido‐ and triazido‐terminated PE (PE‐(N3)2 and PE‐(N3)3) are obtained by the click reactions between PE‐ and coupling agents containing triazido or tetraazido, respectively. Finally, the three‐arm and four‐arm star‐block copolymers, PE‐b‐(PEG)2 and PE‐b‐(PEG)3, are prepared by click reactions between PE‐(N3)2 or PE‐(N3)3 and alkynyl‐terminated PEG. The self‐assembly of the resultant amphiphilic star‐block copolymers in water was investigated by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. It is found that, in water, a solvent selectively good for PEG blocks; these star‐block copolymer chains could self‐assemble to form platelet‐like micelles with insoluble PE blocks as crystalline core and soluble PEG blocks as shell. The confined crystallization of PE blocks in self‐assembled structure formed in aqueous solution is investigated by differential scanning calorimetry. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Radical grafting of polar monomers onto polypropylene by reactive extrusion
Authors: Sadik Tarik , Massardier Valérie , Becquart Frédéric , Taha Mohamed 
Published: January 2013

AbstractPolypropylene (PP) was functionalized in the melt by grafting polar monomers using an internal mixer and a corotating twin‐screw extruder. 2,5‐Bis(tertbutylperoxy)‐2,5‐dimethylhexane (Luperox 101) and dicumyl peroxide (DP) were the used radical initiators. The polar monomers were itaconic acid (IAc), 2‐octen‐1‐ylsuccinic anhydride (OY), 2‐hydroxyethyl methacrylate (HEMA), and 3‐allyloxy‐1,2‐propanediol (AP). Grafting was quantified by FTIR combined to Elemental Analysis. Grafting degree depends mainly on monomer and initiator natures and concentrations. Grafting degree maxima were 3.9, 2, 9.5, and 3.9 wt %, respectively, for IAc, OY, HEMA, and AP. Some properties of the modified PP were evaluated. Thermal analysis indicated that the polarity of PP increased by grafting reaction and size‐exclusion chromatography showed that the grafting was not accompanied by a significant Mw and viscosity decrease. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and Antioxidant Activity of a New Class of Mono‐ and Bis‐Heterocycles
Authors: Mallikarjuna Reddy Guda , Ramachandra Reddy Putta , Padmavathi Venkatapuram , Padmaja Adivireddy 
Published: January 2013

AbstractA new class of mono‐ and bis‐heterocycles, 2‐arylsulfonylaminosulfonylmethyl‐5‐styrylsulfonylmethyloxadiazoles, pyrazolyl oxadiazoles, and isoxazolyl oxadiazoles, were synthesized and tested for their antioxidant activity. The styrylsulfonylmethyloxadiazole 5b showed good antioxidant activity when compared with the standard ascorbic acid.
Adaptive Flocking Control with a Minority of Informed Agents
Authors: Lou Ke , Cui Baotong , Ye Qian 
Published: January 2013

AbstractIn this paper, we address the flocking problem of multiple dynamic mobile agents with a virtual leader in a dynamic proximity network. To avoid fragmentation, we propose a novel flocking algorithm that consists of both an adaptive controller for followers and a feedback controller for the virtual leader. Based on our algorithm, all agents in the group can form a network, maintain connectivity, and track the virtual leader, even when only a minority of agents have access to the information of the virtual leader. Finally, several convincing simulation results are provided that demonstrate 2‐D flocking of a group of agents using the proposed algorithm.
Possibility of application of cytochrome P450 to bioremediation of dioxins
Authors: Sakaki Toshiyuki , Yamamoto Keiko , Ikushiro Shinichi 
Published: January 2013

AbstractDioxins, including polychlorinated dibenzo‐p‐dioxins (PCDDs), dibenzofurans, and coplanar polychlorinated biphenyls, are known to be metabolized by enzymes such as cytochrome (CYP) P450, angular dioxygenase, lignin peroxidase, and dehalogenase. It is noted that all of these enzymes have metal ions in their active centers, and the enzyme systems except for peroxidase each have a distinct electron transport chain. Among these enzyme systems, we have focused on cytochrome P450‐dependent metabolism of dioxins from the viewpoint of practical use for bioremediation. Mammalian and fungal cytochromes P450 showed remarkable activity toward low‐chlorinated PCDDs. In particular, mammalian cytochromes P450 belonging to the CYP1 family showed high activity. Rat CYP1A1 showed high activity toward 2,3,7‐trichloro‐dibenzo‐p‐dioxin but no detectable activity for 2,3,7,8‐tetrachloro‐dibenzo‐p‐dioxin (2,3,7,8‐TCDD). On the basis of these results, we assumed that enlarging the space of the substrate‐binding pocket of rat CYP1A1 might generate TCDD‐metabolizing enzyme. Large‐sized amino acids located at putative substrate‐recognition sites and F‐G loop were substituted for alanine by site‐directed mutagenesis. Finally, we successfully generated 2,3,7,8‐TCDD–metabolizing enzyme by site‐directed mutagenesis of rat CYP1A1. We hope that recombinant microorganisms harboring genetically engineered cytochrome P450 will be used for bioremediation of soil contaminated with PCDDs, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls in the future.
De Novo Biosynthesis of Sexual Pheromone in the Labial Gland of Bumblebee Males
Authors: Žáček Petr , Prchalová‐Horňáková Darina , Tykva Richard , Kindl Jiří , Vogel Heiko , Svatoš Aleš , Pichová Iva , Valterová Irena 
Published: January 2013

AbstractDe novo biosynthesis of male sex pheromone from two bumblebee species (Bombus terrestrisandBombus lucorum) was studied by using in vitro incubations of labial glands (LGs) with radioactive [1,2‐14C]acetate and deuterated [D3]acetate. The labeled substrate was incorporated into several types of compounds, such as terpenic alcohols, fatty acids, esters, and hydrocarbons. A similar incubation of [1,2‐14C]acetate with fat bodies (FB) led to the formation of fatty acids, triacylglycerols (TAG), and hydrocarbons. To support the results from in vitro incubations, PCR analysis of fatty acid synthase (FAS) transcripts in LG and FB was performed. Relative quantification of FAS transcription levels revealed that the abundance of mRNA from the FAS gene is a function of the age ofB. terrestrismales. A comparison of the relative FAS mRNA gene transcription level in FB and LGs ofB. terrestrisandB. lucorummales proved that high biosynthetic activity takes place in the LGs of both species. Together, these results indicate that pheromone components are synthesized de novo in the LG.
New Structural Motif for Carboxylic Acid Perhydrolases
Authors: Yin DeLu (Tyler) , Purpero Vince M. , Fujii Ryota , Jing Qing , Kazlauskas Romas J. 
Published: January 2013

AbstractSome serine hydrolases also catalyze a promiscuous reaction— reversible perhydrolysis of carboxylic acids to make peroxycarboxylic acids. Five X‐ray crystal structures of these carboxylic acid perhydrolases show a proline in the oxyanion loop. Here, we test whether this proline is essential for high perhydrolysis activity using Pseudomonas fluorescens esterase (PFE). The L29P variant of this esterase catalyzes perhydrolysis 43‐fold faster (kcat comparison) than the wild type. Surprisingly, saturation mutagenesis at the 29 position of PFE identified six other amino acid substitutions that increase perhydrolysis of acetic acid at least fourfold over the wild type. The best variant, L29I PFE, catalyzed perhydrolysis 83‐times faster (kcat comparison) than wild‐type PFE and twice as fast as L29P PFE. Despite the different amino acid in the oxyanion loop, L29I PFE shows a similar selectivity for hydrogen peroxide over water as L29P PFE (β0=170 vs. 160 M−1), and a similar fast formation of acetyl‐enzyme (140 vs. 62 U mg−1). X‐ray crystal structures of L29I PFE with and without bound acetate show an unusual mixture of two different oxyanion loop conformations. The type II β‐turn conformation resembles the wild‐type structure and is unlikely to increase perhydrolysis, but the type I β‐turn conformation creates a binding site for a second acetate. Modeling suggests that a previously proposed mechanism for L29P PFE can be extended to include L29I PFE, so that an acetate accepts a hydrogen bond to promote faster formation of the acetyl‐enzyme.