bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification of plasmid DNA from Escherichia coli ferments using anion‐exchange membrane and hydrophobic chromatography
Authors: Guerrero‐Germán Patricia , Montesinos‐Cisneros Rosa Ma. , Prazeres D. Miguel F. , Tejeda‐Mansir Armando
Published: April 2011

A novel downstream bioprocess was developed to obtain purified plasmid DNA (pDNA) from Escherichia coli ferments. The intermediate recovery and purification of the pDNA in cell lysate was conducted using hollow‐fiber tangential filtration and frontal anion‐exchange membrane and elution hydrophobic chromatographies. The purity of the solutions of pDNA obtained during each process stage was investigated. The results show that the pDNA solution purity increased 30‐fold and more than 99% of RNA in the lysate was removed during the process operations. The combination of membrane operations and hydrophobic interaction chromatography resulted in an efficient way to recover pDNA from cell lysates. A better understanding of membrane‐based technology for the purification of pDNA from clarified E. coli lysate was developed in this research.
Plant‐made pharmaceuticals: Leading products and production platforms
Authors: Paul Matthew , Ma Julian K‐C.
Published: April 2011

The number of approaches to recombinant protein production in plants is greater than ever before. Development of these new and improved technologies as production platforms for plant‐made pharmaceuticals has and will continue to create new commercial opportunities in the pharmaceutical sector. However, it is inevitable that no single system will be optimal for the production of all recombinant proteins of interest in plants due to both the physical characteristics and the envisaged therapeutic application of each product. Here, we review a range of promising product/platform pairs emphasizing synergies during production and in clinical trials.
In vivo study of a model tissue‐engineered small‐diameter vascular bypass graft
Authors: Baguneid Mo , de Mel Achala , Yildirimer Lara , Fuller Barry J. , Hamilton George , Seifalian Alexander M.
Published: April 2011

Conventionally used vascular grafts such as polyester (Dacron) or expanded polytetrafluoroethylene perform inadequately as small‐diameter vascular bypass grafts (SDBGs). SDBGs, which can maintain long‐term patency and those that could potentially evolve with the somatic growth, are highly desirable in vascular surgery and thus research into tissue‐engineered blood vessels (TEBVs) is of keen interest. A TEBV was developed by seeding endothelial cells onto a collagen matrix that was cross‐linked and contracted by smooth muscle cells (SMCs). A polyester graft served as a scaffold. Recovery studies (12 TEBVs and seven controls) were carried out to assess in vivo endothelialization and long‐term patency of TEBVs. Hemodynamic observations indicated para‐anastomotic turbulences and high shear stress at anastomosis. Recovery studies demonstrated confluent endothelialization, thrombus‐free surfaces, and patent TEBVs in all cases. Graft incorporation and neovascularization of the scaffold occurred in both hybrid and control grafts. However, thickened neointima formation occurred in TEBV grafts, which was most likely caused by the rigidity of polyester scaffold. Significant perigraft inflammatory changes could be observed in both TEBVs and control grafts at 1, 4, and 8 weeks. In conclusion, the TEBVs demonstrated satisfactory performance as an infra–renal–aortic graft in a porcine model. The TEBV serves as a promising model and facilitates the development of a TEBV in a clinical setting, potentially with human stem cells and with more biocompatible, biodegradable scaffolds that are mechanically more compliant with natural vessels.
Simulation terroristischer Anschläge in Massenverkehrsmitteln
Authors: Larcher Martin , Gebbeken Nobert , Solomos George , Casadei Folco
Published: April 2011

Aufgrund terroristischer Anschläge sind Baustrukturen auch Explosionen ausgesetzt. In der vorliegenden Untersuchung werden numerische Simulationen verwendet, um die Auswirkungen von Detonationen in schienengebundenen Massenverkehrsmitteln zu untersuchen. Es werden verschiedene Parameter für die Detonation innerhalb eines Waggons variiert. An einem langen Zug ohne Unterteilungen werden die Auswirkungen einer Explosion im Tunnel im Vergleich zu der im Frei‐Feld gezeigt. Ein Risikomodell hilft, die Auswirkungen auf Passagiere zu erkennen. Anhand dieses Modells lassen sich die Einflussfaktoren auf das Risiko für die Passagiere herausarbeiten. Es zeigt sich, dass insbesondere Einbauten wie Türen oder Windfänge helfen, die Detonationswelle zu reduzieren.

Simulation of terrorist attacks in mass transport systems.Recent terrorist attacks have shown that civil structures are also exposed to detonations. Numerical simulations are used here to investigate the influence of explosions in mass transport systems. Several attack scenarios are examined. Parameters of detonations inside a wagon are varied. A long train without any intersections or compartments is also considered and the effects of detonations inside a tunnel or in free‐field are investigated. A risk model depending on the blast parameters calculated, helps to determine the influence of the detonation onto passengers. It can be shown that internal structures like compartments or windscreens can significantly reduce the blast wave consequences.
Besondere Aspekte bei der Verwendung von Gitterträger‐Elementdecken zur Herstellung punktgestützter Flachdecken
Authors: Held Markus , Welsch Torsten
Published: April 2011

Seit einiger Zeit werden Gitterträger‐Elementdecken verstärkt auch bei der Herstellung punktgestützter Flachdecken eingesetzt. Dabei wird zuweilen übersehen, dass es gegenüber liniengelagerten Decken einige Besonderheiten zu beachten gilt. Nachfolgend wird auf einige dieser kritischen Punkte hingewiesen.

Particular aspects concerning the use of ribbed slab floors to the construction of flat slabs. Ribbed slab floors are also used for the construction of flat slabs. Sometimes it is ignored, that some special aspects have to be considered in comparison to line supported slabs. In the following pages some critical points are emphasized.
Umsetzung einer Meerwasserkühlung beim Kraftwerk Eemshaven (NL) — eine bautechnische Herausforderung im Bereich Tief‐ und Wasserbau
Authors: Ulke Bernd , Börg Bernd
Published: April 2011

Die RWE Eemshaven Holding B.V. baut am Standort Eemshaven (NL) ein Steinkohlekraftwerk mit Meerwasserkühlung. Um mit der Hauptkühlwasserleitung den Deich zu unterqueren, ist das sog. Einleitbauwerk bzw. Kühlwasserauslassbauwerk erforderlich. Über die bis Dezember 2009 erfolgten Arbeiten bis zur Betonage der ersten Unterwasserbetonsohle (landseitige Baugrube) wurde bereits in [1] berichtet.
Prediction models for complications in trauma patients
Authors: de Jongh M A C , Bosma E , Verhofstad M H J , Leenen L P H
Published: April 2011

Background

Because the death rate among the total trauma population is low, other performance indicators in addition to the classical dependent variable mortality are required to assess the overall quality of trauma care. The aim of this study was to develop and validate a prediction model for the occurrence of complications that can be used to adjust a measure of quality of trauma care for case mix.

Methods

Complications recorded in a trauma registry between 1997 and 2008 were analysed. Formulas for different types of complication (institution- or diagnosis-related) derived from logistic regression models were used to calculate the probability of absence of complications (PAC). Discriminative power was tested by calculating the area under the receiver operating characteristic curve (AUC) in test and validation samples. Calibration was tested using Hosmer and Lemeshow methodology.

Results

Some 5944 surgical trauma admissions were included in the analysis. A significant association between both institution- and diagnosis-related complications and Injury Severity Score was found. Diagnosis-related complications were also associated with Glasgow Coma Score and age. The AUCs of the PACs for institution- and diagnosis-related complications were 0·64 and 0·75 respectively in the test sample, and 0·66 and 0·76 in the validation sample. The AUCs increased when the outcomes of the models were divided into subcategories of complications. Hosmer and Lemeshow tests were not significant for all models, except that for institutional complications.

Conclusion

To predict complications, a distinction should be made between institution- and diagnosis-related complications. The development of more detailed diagnosis-related prediction models is preferable because of better performance. The formulas predicting the PAC can be used to compare expected and observed complications.
Smoking and the risk of diverticular disease in women
Authors: Hjern F , Wolk A , Håkansson N
Published: April 2011

Background

The relationship between smoking and the risk of diverticular disease is unclear. An observational cohort study was undertaken to investigate the association between smoking and diverticular disease.

Methods

Women in the Swedish Mammography Cohort born between 1914 and 1948 were followed from 1997 to 2008. Information on smoking and other lifestyle factors was collected through questionnaires. Patients with symptomatic diverticular disease were identified from Swedish national registers. Relative risks (RRs) of symptomatic diverticular disease (resulting in hospital admission or death) according to smoking status were estimated using Cox proportional hazards models.

Results

Of 35 809 women included in the study, 561 (1·6 per cent) had symptomatic diverticular disease. In multivariable analysis, current smokers had an increased risk of symptomatic diverticular disease compared with non-smokers after adjustment for age, intake of dietary fibre, diabetes, hypertension, use of acetylsalicylic acid, non-steroidal anti-inflammatory drugs or steroid medication, alcohol consumption, body mass index, physical activity and level of education (RR 1·23, 95 per cent confidence interval 0·99 to 1·52). Past smokers also had an increased risk (RR 1·26, 1·02 to 1·56). Smokers had a higher risk of developing a diverticular perforation/abscess than non-smokers (RR 1·89, 1·15 to 3·10).

Conclusion

Smoking is associated with symptomatic diverticular disease.
Development of a virtual winder for computer‐aided education using Virtools
Authors: Liu Jihong , Jiang Hongxia
Published: April 2011

Since operation of virtual winder can relieve the problem of lack of experiment on real equipments, virtual winder can be valuable complements to physical winder operation experiment. Virtools is the most widely used software for creating 3D VR environment. In this article, using Virtools to construct a virtual winder is demonstrated in detail by dividing the whole process into five steps: (1) creates 3D winder models in 3ds Max; (2) exports the models to Virtools format using Expert plugins (3ds Max Exporter); (3) designs scenes including cameras and lighters; (4) constructs the virtual winder including Behavior Building Block (BB), Scripts, and Virtools Scripting Language (VSL); (5) synthesizes and exports interactive coursewares of the virtual winder. The considerations and discussions in this article may be useful for building system of virtual education equipment in other subject areas. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22: 120–130, 2014
Application of Cross‐Flow Microfiltration for Purifying Solvent Naphtha with Ceramic Membranes
Authors: Zeng J. , Zheng L. , Sun X. , He Q.
Published: April 2011

The microfiltration process of solvent naphtha 200 containing impurities was studied using multichannel ceramic membranes with pore diameters of 0.5 and 0.8 μm. The effects of operating time, transmembrane pressure, cross‐flow velocity, and temperature on permeate flux and rejection were investigated. The scanning electron microscop and energy dispersive spectrometry were conducted for the clean and fouled membranes. Effect of backflushing on permeate flux was also studied. Results show that it is possible to recover over 94 % of the original flux by a program of backflushing. A concentration process was carried out and furthermore, various membrane resistances were calculated. Finally, commercial detergent, HNO3, and NaOH + NaClO cleaning stages were used for the 0.5‐μm membrane.
In Situ Microscopy for Online Monitoring of Enzymatic Processes
Authors: Prediger A. , Bluma A. , Höpfner T. , Lindner P. , Beutel S. , J. Müller J. , Hilterhaus L. , Liese A. , Scheper T.
Published: April 2011

In situ Microscopy (ISM) is an optical analysis method that allows non‐invasive monitoring of processes in real‐time. In this article online monitoring of enzyme carriers and the determination of their mechanical stability are presented as new application areas for ISM. As proof of principle the fragmentation of Lewatit VP OC 1600 particles in a stirred tank reactor is tracked. The image algorithm that was used to analyze the acquired image data is described and the results of the stability study are shown. Additional application possibilities of ISM in the area of two‐phase systems are demonstrated.
Calcium Manganese Oxides as Oxygen Evolution Catalysts: O2 Formation Pathways Indicated by 18O‐Labelling Studies
Authors: Shevela Dmitriy , Koroidov Sergey , Najafpour M. Mahdi , Messinger Johannes , Kurz Philipp
Published: April 2011

Oxygen evolution catalysed by calcium manganese and manganese‐only oxides was studied in 18O‐enriched water. Using membrane‐inlet mass spectrometry, we monitored the formation of the different O2 isotopologues 16O2, 16O18O and 18O2 in such reactions simultaneously with good time resolution. From the analysis of the data, we conclude that entirely different pathways of dioxygen formation catalysis exist for reactions involving hydrogen peroxide (H2O2), hydrogen persulfate (HSO5−) or single‐electron oxidants such as CeIV and [RuIII(bipy)3]3+. Like the studied oxide catalysts, the active sites of manganese catalase and the oxygen‐evolving complex (OEC) of photosystem II (PSII) consist of μ‐oxido manganese or μ‐oxido calcium manganese sites. The studied processes show very similar 18O‐labelling behaviour to the natural enzymes and are therefore interesting model systems for in vivo oxygen formation by manganese metalloenzymes such as PSII.
The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy
Authors: Li Dan , Yu Qiang , Li Shan‐Shan , Wan Hai‐Qin , Liu Lian‐Jun , Qi Lei , Liu Bin , Gao Fei , Dong Lin , Chen Yi
Published: April 2011

NO reduction by CO was investigated over CuO/γ‐Al2O3, Mn2O3/γ‐Al2O3, and CuOMn2O3/γ‐Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO‐pretreated CuOMn2O3/γ‐Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2‐temperature‐programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ‐Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ‐Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ‐Al2O3 and Mn2O3/γ‐Al2O3 catalysts, the ‐Cu‐O‐Cu‐ and ‐Mn‐O‐Mn‐ species were formed on the surface of γ‐Al2O3, respectively; but for the fresh CuOMn2O3/γ‐Al2O3 catalyst, ‐Cu‐O‐Mn‐ species existed on the surface of γ‐Al2O3. After CO pretreatment, ‐Cu‐□‐Cu‐ and ‐Mn‐□‐Mn‐ (□ represents surface oxygen vacancy (SOV)) species would be formed in CO‐pretreated CuO/γ‐Al2O3 and CO‐pretreated Mn2O3/γ‐Al2O3 catalysts, respectively; whereas ‐Cu‐□‐Mn‐ species existed in CO‐pretreated CuOMn2O3/γ‐Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO‐pretreated CuO‐Mn2O3/γ‐Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature‐programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO‐pretreated CuO/γ‐Al2O3, Mn2O3/γ‐Al2O3, and CuOMn2O3/γ‐Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO‐pretreated CuOMn2O3/γ‐Al2O3 catalyst were significantly different to SOVs formed in CO‐pretreated CuO/γ‐Al2O3 and Mn2O3/γ‐Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.
Energy‐Level Tailoring in a Series of Redox‐Rich Quinonoid‐Bridged Diruthenium Complexes Containing Tris(2‐pyridylmethyl)amine as a Co‐Ligand
Authors: Weisser Fritz , Huebner Ralph , Schweinfurth David , Sarkar Biprajit
Published: April 2011

Reactions of [{Ru(tmpa)}2(μ‐Cl)2][ClO4]2, (2[ClO4]2, tmpa=tris(2‐pyridylmethyl)amine) with 2,5‐dihydroxy‐1,4‐benzoquinone (L1), 2,5‐di‐[2,6‐(dimethyl)‐anilino]‐1,4‐benzoquinone (L2), or 2,5‐di‐[2,4,6‐(trimethyl)‐anilino)]‐1,4‐benzoquinone (L3) in the presence of a base led to the formation of the dinuclear complexes [{Ru(tmpa)}2(μ‐L1−2 H)][ClO4]2 (3[ClO4]2), [{Ru(tmpa)}2(μ‐L2−2 H)][ClO4]2 (4[ClO4]2), and [{Ru(tmpa)}2(μ‐L3−2 H)][ClO4]2 (5[ClO4]2). Structural characterization of 5[ClO4]2 showed the localization of the double bonds within the quinonoid ring and a twisting of the mesityl substituents with respect to the quinonoid plane. Cyclic voltammetry of the complexes show two reversible oxidation and quinonoid‐based reduction processes. Results obtained from UV/Vis/NIR and EPR spectroelectrochemistry are invoked to discuss ruthenium‐ versus quinonoid‐ligand‐centered redox activity. The complex 3[ClO4]2 is compared to the reported complex [{Ru(bpy)}2(μ‐L1−2 H)]2+ (12+, bpy=2,2′‐bipyridine). The effects of substituting the bidentate and better π‐accepting bpy co‐ligands with tetradentate tmpa ligands [pure σ‐donating (amine) as well as σ‐donating and π‐accepting (pyridines)] on the redox and electronic properties of the complexes are discussed. Comparisons are also made between complexes containing the dianionic forms of the all‐oxygen‐donating L1 ligand with the L2 and L3 ligands containing an [O,N,O,N] donor set. The one‐electron oxidized forms of the complexes show absorption in the NIR region. The position as well as the intensity of this band can be tuned by the substituents on the quinonoid bridge. In addition, this band can be switched on and off by using tunable redox potentials, making such systems attractive candidates for NIR electrochromism.
Nitrogen Dynamics and Reactivity of Chiral Aziridines: Generation of Configurationally Stable Aziridinyllithium Compounds
Authors: Degennaro Leonardo , Mansueto Rosmara , Carenza Elisa , Rizzi Rosanna , Florio Saverio , Pratt Lawrence M. , Luisi Renzo
Published: April 2011

Diastereomeric oxazolinylaziridines (R,R)‐9 and (R,S)‐9 have been regioselectively lithiated at the α‐position with respect to the oxazolinyl ring. The resulting aziridinyllithium compounds proved to be chemically and configurationally stable under the experimental conditions used, thus furnishing, upon trapping with electrophiles, chiral 2,2‐disubstituted aziridines, in contrast to the corresponding α‐lithiated oxazolinyloxiranes that have been reported to be chemically stable but configurationally unstable. This peculiar behavior of the nitrogen‐bearing heterocycle has been rationalized on the basis of DFT calculations and the observed dynamics of the aziridine nitrogen atom. The DFT analysis allowed the disclosure of a solvent‐dependent differing stability of diastereomeric lithiated aziridines (R,R)‐9‐Li and (R,S)‐9‐Li, suggesting η3‐coordinated oxazolinylaziridinyllithium compounds as likely intermediates. Such intermediates could be the result of a dynamically controlled lithiation that relies on the preliminary formation of a complex between the lithiating agent and the oxazolinyl ring. According to this model, the competing complexation of the lithiating agent by the lone pair of electrons on the aziridine nitrogen would cause addition to the oxazoline CN bond, thus ending up with the formation of oxazolidines, which are precursors of useful chiral ketoaziridines. The proposed model has been also supported by estimating the nitrogen inversion barrier by dynamic NMR spectroscopic experiments.
Electron Exchange Columns through Entrapment of a Nickel Cyclam in a Sol–Gel Matrix
Authors: Lavi Yair , Burg Ariela , Maimon Eric , Meyerstein Dan
Published: April 2011

An electron exchange column (analogous to ion exchange columns) was developed using the unique redox properties of the nickel–tetraazamacrocyclic complexes (nickel cyclam [NiIIL1]2+) and nickel–trans‐III‐meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, ([NiIIL2]2+), and the physical and chemical stability of the ceramic materials using the sol–gel process to entrap the complexes. The entrapment by the biphasic sol–gel method is based on non‐covalent bonds between the matrix and the complex; therefore the main problem was leaching. Parameters controlling the leaching were investigated. Redox cycles with the reducing agent ascorbic acid, and persulfate as the oxidizing agent were performed.
Degradable Dual pH‐ and Temperature‐Responsive Photoluminescent Dendrimers
Authors: Shen Youqing , Ma Xinpeng , Zhang Bo , Zhou Zhuxian , Sun Qihang , Jin Erlei , Sui Meihua , Tang Jianbin , Wang Jinqiang , Fan Maohong
Published: April 2011

Poly(β‐aminoester) dendrimers have been prepared. These systems represent the first degradable dual pH‐ and temperature‐responsive dendrimers displaying photoluminescence. The pH/temperature sensitivities are interrelated; the lower critical solution temperature of the dendrimer decreases as the pH of the solution is increased. The sensitivities are mainly due to phase changes of the surface groups with changes in pH or temperature. These dual‐responsive dendrimers are very useful in drug delivery. They may be loaded with a hydrophobic drug at low temperature without using organic solvents. The loaded drug is released very slowly and steadily at 37 °C and physiological pH, but can be quickly released at acidic pH, for example the lysosomal pH (pH 4–5), for intracellular drug release. These dendrimers also display strong photoluminescence, which can be exploited for monitoring drug loading and release. Thus, poly(β‐aminoester) dendrimers constitute ideal drug carriers since their thermal sensitivity allows the loading of drugs without using organic solvents, their pH sensitivity permits fast intracellular drug release, and their photoluminescence provides a means of monitoring drug loading and release.
Triptycene‐Derived Oxacalixarenes as New Wheels for the Synthesis of [2]Rotaxanes: Acid–Base‐ and Metal‐Ion‐Switchable Complexation Processes
Authors: Hu Shu‐Zhen , Chen Chuan‐Feng
Published: April 2011

A pair of triptycene‐derived oxacalixarenes, 1 a and 1 b, containing two naphthyridine subunits have been synthesized by a convenient one‐pot approach. Macrocycles 1 a and 1 b are diastereomers, with 1 a being a cis isomer with a boat‐like 1,3‐alternate conformation and 1 b being a trans isomer with a curved boat‐like conformation in the solid state. Both 1 a and 1 b have fixed conformations in solution at room temperature, as revealed by variable‐temperature 1H NMR spectroscopy experiments. It was found that oxacalixarenes 1 a and 1 b could both form 1:1 [2]pseudorotaxane‐type complexes with paraquat derivatives with different functional groups in solution and in the solid state, which resulted in the further synthesis of a pair of novel isomeric [2]rotaxanes. Moreover, the controlled dethreading and rethreading processes of the [2]pseudorotaxanes were also easily achieved by acid–base stimuli or Hg2+ association/dissociation.
Oligopyrrole Macrocycles: Receptors and Chemosensors for Potentially Hazardous Materials
Authors: Rambo Brett M. , Sessler Jonathan L.
Published: April 2011

Oligopyrroles represent a diverse class of molecular receptors that have been utilized in a growing number of applications. Recently, these systems have attracted interest as receptors and chemosensors for hazardous materials, including harmful anionic species, high‐valent actinide cations, and nitroaromatic explosives. These versatile molecular receptors have been used to develop rudimentary colorimetric and fluorimetric assays for hazardous materials.
Evaluation of phosphinoamidoester‐derived Pd catalysts in the asymmetric allylic alkylation reaction: Theoretical studies and mechanistic insights
Authors: Marinho Vanda R. D. , Ramalho J.P.Prates , Rodrigues Ana Isabel , Burke Anthony J.
Published: April 2011

Two simple hemilabile P,O‐coordinating phosphinoamidoester ligands 6a and 6b were synthesized and studied in the Pd(0)‐catalyzed asymmetric allylic alkylation of rac‐1,3‐diphenylpropenyl acetate affording a highest ee of 83% ee with 6a. To gain an insight into the actual mechanism of this catalytic reactions, which had previously been investigated with a first generation family of P,O‐coordinating phosphinoamido‐alcohol ligands—4a and 4b—a semiempirical computational study was carried out with the Pd‐allyl complexes formed from both 4a and 6a including Hitchcock's phosphinoamido‐alcohol ligand 5 (R1 = H, R2 = Ph). The results of this study substantiate a working model that has previously been proposed for this reaction using hemilabile P,O‐coordinating phosphinoamido‐type ligands. Chirality 2011 © 2011 Wiley‐Liss, Inc
Organocatalytic aza‐Michael/retro‐aza‐Michael reaction: Pronounced chirality amplification in aza‐Michael reaction and racemization via retro‐aza‐Michael reaction
Authors: Cai Yong‐Feng , Li Li , Luo Meng‐Xian , Yang Ke‐Fang , Lai Guo‐Qiao , Jiang Jian‐Xiong , Xu Li‐Wen
Published: April 2011

A detailed experimental investigation of an aza‐Michael reaction of aniline and chalcone is presented. A series of Cinchona alkaloid‐derived organocatalysts with different functional groups were prepared and used in the aza‐Michael and retro‐aza‐Michael reaction. There was an interesting finding that a complete reversal of stereoselectivity when a benzoyl group was introduced to the cinchonine and cinchonidine. The chirality amplification vs. time proceeds in the quinine‐derived organocatalyst containing silicon‐based bulky group, QN‐TBS, ‐catalyzed aza‐Michael reaction under solvent‐free conditions. In addition, we have demonstrated for the first time that racemization was occurred in suitable solvents under mild conditions due to retro‐aza‐Michael reaction of the Michael adduct of aniline with chalcone. These indicate the equilibrium of retro‐aza‐Michael reaction and aza‐Michael reaction produce the happening of chirality amplification in aza‐Michael reaction and racemization via retro‐aza‐Michael reaction under different conditions, which would be beneficial to the development of novel chiral catalysts for the aza‐Michael reactions. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Growth of Textured Adenine Thin Films to Exhibit only Chiral Faces
Authors: Capitán María Jose , Otero Roberto , Álvarez Jesús , Miranda Rodolfo
Published: April 2011

The growth of adenine on Au(111) from the submonolayer up to several microns film thickness is studied by combining STM and surface X‐ray diffraction techniques. The study shows that adenine thin films are composed of highly textured crystallites with the reported α‐adenine crystal structure in such a way that they only exhibit (001)‐faces. Such faces, with chiral p2 symmetry planes, have an average size of 15 nm. Thus, the formed adenine films reported herein, which expose only chiral and biocompatible faces, might find applications such as enantioselective heterogeneous catalysts for the chemical and pharmaceutical industries.
Urovysion: Considerations on modifying current evaluation scheme, including immunophenotypic targeting and locally set, statistically derived diagnostic criteria
Authors: Pajor Gabor , Somogyi Laszlo , Melegh Bela , Alpar Donat , Kajtar Bela , Farkas Laszlo , Kneif Maria , Bollmann Daniel , Pajor Laszlo , Sule Norbert
Published: April 2011

Urovysion multitarget fluorescence in situ hybridization (FISH) assay is a promising tool for detection of bladder cancer, however, there is still no consensus regarding abnormal signal pattern and cut‐off level, and the recommended targeting carries limitations similar to urine cytology. Aim of this study was to explore diagnostic benefits of a recently introduced method featuring target specific genotyping, as well as to investigate the feasibility of locally and statistically determined cut‐off, compared with conventional evaluation scheme. Histology, cytology, and comparative FISH approaches were performed on 42 patients with high clinical suspicion for urothelial carcinoma (UC). FISH parallels were (1) Urovysion‐alone (according to manufacturer's instruction); (2) Targeted‐Urovysion (cytokeratin7 immunophenotyping followed by Urovysion), both of which evaluated by both conventional and statistical evaluation scheme. For statistical evaluation cut‐offs and sufficient sample size were determined on controls and ratio of positive cells was recorded, whereas conventional evaluation relied on manufacturer's recommendations. The specificity of cytology, Urovysion‐alone in general and targeted‐Urovysion in general appeared 86%, 86%, and 100%, respectively. In the same comparison, overall sensitivity was 60%, 80%, and 93%, respectively. In superficial cases sensitivity was 48% for cytology, 72% for Urovysion‐alone and 91% for targeted‐Urovysion, while no prominent differences were seen in muscle invasive cases. The ratio of FISH positive cells was proportionate with both stage and grade, however, targeted genotyping could separate high grade/high stage cases more effectively. In conclusion, CK7 targeting raises diagnostic efficiency of Urovysion, and could be an ideal tool for identifying tumor cells in ambiguous cases or when other tumors are present. Statistical evaluation produces accuracy comparable with results of conventional evaluation, and with laboratories setting cut‐offs individually but according harmonized protocol, it could aid method standardization. Furthermore, by providing additional quantitative information about tumor characteristics, is likely to have therapy relevant value in the future. © 2011 International Society for Advancement of Cytometry
Decode‐and‐forward with full‐duplex relaying
Authors: Rui Xianyi , Hou Jia , Zhou Liulei
Published: April 2011

This paper addresses the full‐duplex relaying. Some expressions for outage and average capacity of a two‐hop cooperative system with a full‐duplex relay are derived under an independent but not identically distributed Rayleigh fading environment. Using these expressions, we provide the performance analysis without Monte Carlo simulations. The impact of interference between the relay output and input is investigated. Copyright © 2011 John Wiley & Sons, Ltd.
Imaging adhesion and signaling dynamics in Xenopus laevis growth cones
Authors: Santiago‐Medina Miguel , Myers Jonathan P. , Gomez Timothy M.
Published: April 2011

Xenopus laevis provides a robust model system to study cellular signaling and downstream processes during development both in vitro and in vivo. Intracellular signals must function within highly restricted spatial and temporal domains to activate specific downstream targets and cellular processes. Combining the versatility of developing Xenopus neurons with advances in fluorescent protein biosensors and imaging technologies has allowed many dynamic cellular processes to be visualized. This review will focus on the techniques we use to visualize and measure cell signaling, motility and adhesion by quantitative fluorescence microscopy in vitro and in vivo. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 585–599, 2012
Msx1 and Msx2 in limb mesenchyme modulate digit number and identity
Authors: Bensoussan‐Trigano Vardina , Lallemand Yvan , Saint Cloment Cécile , Robert Benoît
Published: April 2011

Msx1 and Msx2 encode homeodomain transcription factors that play a crucial role in limb development. However, the limb phenotype of the double Msx1null/null
Msx2null/null mutant is difficult to analyze, particularly along the anteroposterior axis, because of the complex effects of the double mutation on both ectoderm‐ and mesoderm‐derived structures. Namely, in the mutant, formation of the apical ectodermal ridge (AER) is impaired anteriorly and, consequently, the subjacent mesenchyme does not form. Using the Cre/loxP system, we investigated the respective roles of Msx genes in ectoderm and mesoderm by generating conditional mutant embryos with no Msx activity solely in the mesoderm. In these mutants, the integrity of the ectoderm‐derived AER was maintained, allowing formation of the anterior mesenchyme. With this strategy, we demonstrate that mesenchymal expression of Msx1 and Msx2 is required for proper Shh and Bmp4 signaling to specify digit number and identity. Developmental Dynamics 240:1190–1202, 2011. © 2011 Wiley‐Liss, Inc.
Distinct and redundant expression and transcriptional diversity of MEIS gene paralogs during chicken development
Authors: Sánchez‐Guardado Luis Óscar , Irimia Manuel , Sánchez‐Arrones Luisa , Burguera Demián , Rodríguez‐Gallardo Lucía , Garcia‐Fernández Jordi , Puelles Luis , Ferran José Luis , Hidalgo‐Sánchez Matías
Published: April 2011

Members of the Meis family of TALE homeobox transcription factors are involved in many processes of vertebrate development and morphogenesis, showing extremely complex transcriptional and spatiotemporal expression patterns. In this work, we performed a comprehensive study of chicken Meis genes using multiple approaches. First, we assessed whether the chicken genome contains a Meis3 ortholog or harbors only two Meis genes; we gathered several lines of evidence pointing to a specific loss of the Meis3 ortholog in an early ancestor of birds. Next, we studied the transcriptional diversity generated from chicken Meis genes through alternative splicing during development. Finally, we performed a detailed analysis of chick Meis1/2 expression patterns during early embryogenesis and organogenesis. We show that the expression of both Meis genes begins at the gastrulation stage in the three embryonic layers, presenting highly dynamic patterns with overlapping as well as distinct expression domains throughout development. Developmental Dynamics 240:1475–1492, 2011. © 2011 Wiley‐Liss, Inc.
Ectopic expression of Cux1 is associated with reduced p27 expression and increased apoptosis during late stage cyst progression upon inactivation of Pkd1 in collecting ducts
Authors: Paul Binu M. , Vassmer Dianne , Taylor Aaron , Magenheimer Lynn , Carlton Carol G. , Piontek Klaus B. , Germino Gregory G. , Vanden Heuvel Gregory B.
Published: April 2011

Polycystic kidney diseases (PKD) are inherited disorders characterized by fluid‐filled cysts primarily in the kidneys. We previously reported differences between the expression of Cux1, p21, and p27 in the cpk and Pkd1 null mouse models of PKD. Embryonic lethality of Pkd1 null mice limits its study to early stages of kidney development. Therefore, we examined mice with a collecting duct specific deletion in the Pkd1 gene. Cux1 was ectopically expressed in the cyst lining epithelial cells of newborn, P7 and P15 Pkd1CD mice. Cux1 expression correlated with cell proliferation in early stages of cystogenesis, however, as the disease progressed, fewer cyst lining cells showed increased cell proliferation. Rather, Cux1 expression in late stage cystogenesis was associated with increased apoptosis. Taken together, our results suggest that increased Cux1 expression associated with apoptosis is a common feature of late stage cyst progression in both the cpk and Pkd1CD mouse models of PKD. Developmental Dynamics 240:1493–1501, 2011. © 2011 Wiley‐Liss, Inc.
Salamander limb development: Integrating genes, morphology, and fossils
Authors: Fröbisch Nadia B. , Shubin Neil H.
Published: April 2011

The development of the tetrapod limb during skeletogenesis follows a highly conservative pattern characterized by a general proximo‐distal progression in the establishment of skeletal elements and a postaxial polarity in digit development. Salamanders represent the only exception to this pattern and display an early establishment of distal autopodial structures, specifically thebasale commune, an amalgamation of distal carpal and tarsal 1 and 2, and a distinct preaxial polarity in digit development. This deviance from the conserved tetrapod pattern has resulted in a number of hypotheses to explain its developmental basis and evolutionary history. Here we summarize the current knowledge of salamander limb development under consideration of the fossil record to provide a deep time perspective of this evolutionary pathway and highlight what data will be needed in the future to gain a better understanding of salamander limb development specifically and tetrapod limb development and evolution more broadly. Developmental Dynamics 240:1087–1099, 2011. © 2011 Wiley‐Liss, Inc.
Gdnf is mitogenic, neurotrophic, and chemoattractive to enteric neural crest cells in the embryonic colon
Authors: Mwizerwa Olive , Das Pragnya , Nagy Nandor , Akbareian Sophia E. , Mably John D. , Goldstein Allan M.
Published: April 2011

Glial‐derived neurotrophic factor (Gdnf) is required for morphogenesis of the enteric nervous system (ENS) and it has been shown to regulate proliferation, differentiation, and survival of cultured enteric neural crest–derived cells (ENCCs). The goal of this study was to investigate its in vivo role in the colon, the site most commonly affected by intestinal neuropathies such as Hirschsprung's disease. Gdnf activity was modulated in ovo in the distal gut of avian embryos using targeted retrovirus‐mediated gene overexpression and retroviral vector‐based gene silencing. We find that Gdnf has a pleiotropic effect on colonic ENCCs, promoting proliferation, inducing neuronal differentiation, and acting as a chemoattractant. Down‐regulating Gdnf similarly induces premature neuronal differentiation, but also inhibits ENCC proliferation, leading to distal colorectal aganglionosis with severe proximal hypoganglionosis. These results indicate an important role for Gdnf signaling in colonic ENS formation and emphasize the critical balance between proliferation and differentiation in the developing ENS. Developmental Dynamics 240:1402–1411, 2011. © 2011 Wiley‐Liss, Inc.
Ephrin/ephrin receptor expression during early stages of mouse inner ear development
Authors: Saeger Bernhard M. , Suhm Martina , Neubüser Annette
Published: April 2011

Ephrins and their tyrosine kinase receptors (Ephs) are a highly conserved family of signaling proteins with various functions during embryonic development. Among others, Eph/ephrin signaling is involved in regulating axon guidance, cell migration, and tissue border formation through inducing modifications of the actin cytoskeleton and cell adhesion. During development ephrins and Ephs are expressed in spatially and temporarily regulated patterns in a wide range of tissues. Here, we analyzed the expression of seven members of the Eph and four member of the ephrin family during early stages of mouse inner ear development by whole‐mount in situ hybridization. We detected expressions of EphA2, EphA4, EphA7, EphB1, ephrinA4, and ephrinA5 in and around the forming otic placode between embryonic day (E) 8.5 and E10, and report their detailed expression patterns. Our results reveal dynamic expression of several members of the ephrin/Eph family consistent with functions in otic placode development, invagination and neuroblast delamination. Developmental Dynamics 240:1578–1585, 2011. © 2011 Wiley‐Liss, Inc.
Equivalence‐point electromigration acid–base titration via moving neutralization boundary electrophoresis
Authors: Yang Qing , Fan Liu‐Yin , Huang Shan‐Sheng , Zhang Wei , Cao Cheng‐Xi
Published: April 2011

In this paper, we developed a novel method of acid–base titration, viz. the electromigration acid–base titration (EABT), via a moving neutralization boundary (MNR). With HCl and NaOH as the model strong acid and base, respectively, we conducted the experiments on the EABT via the method of moving neutralization boundary for the first time. The experiments revealed that (i) the concentration of agarose gel, the voltage used and the content of background electrolyte (KCl) had evident influence on the boundary movement; (ii) the movement length was a function of the running time under the constant acid and base concentrations; and (iii) there was a good linearity between the length and natural logarithmic concentration of HCl under the optimized conditions, and the linearity could be used to detect the concentration of acid. The experiments further manifested that (i) the RSD values of intra‐day and inter‐day runs were less than 1.59 and 3.76%, respectively, indicating similar precision and stability in capillary electrophoresis or HPLC; (ii) the indicators with different pKa values had no obvious effect on EABT, distinguishing strong influence on the judgment of equivalence‐point titration in the classic one; and (iii) the constant equivalence‐point titration always existed in the EABT, rather than the classic volumetric analysis. Additionally, the EABT could be put to good use for the determination of actual acid concentrations. The experimental results achieved herein showed a new general guidance for the development of classic volumetric analysis and element (e.g. nitrogen) content analysis in protein chemistry.
Evaluation of the free radical scavenging capability of wheat extracts by capillary electrophoresis and multivariate curve resolution
Authors: Helmja Kati , Vaher Merike , Kaljurand Mihkel
Published: April 2011

In the current work, phenolic acids were analysed and their radical scavenging activity evaluated by CE, including the quantification of overlapping peaks by applying the multivariate curve resolution (MCR) method. To investigate radical scavenging activity, the solution of phenolic acids was treated with a stable free 2,2‐diphenyl‐1‐picrylhydrazyl radical of different concentrations and the radical scavenging activity of the reaction mixture was monitored. The radical scavenging reaction was also applied to wheat bran extracts. The overlapping peaks on the electropherograms of both mixtures of standard compounds and extracts of different wheat bran varieties were resolved by using the MCR method, assuming that the overlapping compounds have different UV spectra. MCR enabled the insufficient resolution between syringic and ferulic acids to be effectively resolved.
Simple and rapid CE‐UV method for the assessment of trail pheromone compounds of leaf‐cutting ants' venom glands
Authors: Leitão Amanda Araujo , de Lacerda Miranda Paulo Cesar Muniz , Simionato Ana Valéria Colnaghi
Published: April 2011

Leaf‐cutting ants cause large losses in several crops around the world. In the ant species Atta sexdens, each colony comprises up to 5 million individuals. In order to keep a close connection among such a large number of individuals, an efficient chemical communication system is necessary. Among other different substances, these animals use alkylpyrazines to mark their trails and to guide ant workers from the nest to their sources of food. In this study, CE‐UV was used to apply a method for qualitative analysis of venom gland components of leaf‐cutting ants. Mobility of these compounds proved to be a function of the ionization capability of these bases as well as their volumes. Migration order was thoroughly explained in terms of such parameters. The best analysis conditions were achieved with a BGE composed by 0.8% formic acid plus 20% methanol in water, hydrodynamic injection, and application of external pressure. Such analysis conditions may be easily applied in CE‐MS analyses as well. CE‐UV analyses proved to be as adequate as GC to analyze such compounds due to system detectability (LD ≅ 0.005 mmol/L), separation efficiency (from 5.07×104 to 1.23×105 theoretical plates), and resolution (minimum of 2.35). In addition, analysis time was ca. 15 min, which shows another advantage of CE analysis when compared with GC. Although the analytes are found in concentrations as low as 50 ng/venom glands, four putative pyrazine ring moiety substances could be detected in real samples, due to sample stacking and use of a capillary with extended detection cell.
Mixed ligand monolithic columns for reversed‐phase capillary electrochromatography via hydrophobic and π interactions
Authors: Karenga Samuel , Rassi Ziad El
Published: April 2011

Novel mixed ligand monoliths (MLM) for capillary electrochromatography (CEC) of a wide range of solutes differing in both polarity and size were introduced. The MLM capillary columns were based on the different compositions of octadecyl acrylate (ODA) and 2‐naphthyl methacrylate (NAPM) monomers in the presence of trimethylolpropane trimethacrylate (TRIM) crosslinker and a ternary porogenic solvent made up of cyclohexanol, ethylene glycol, and water. As expected, the magnitude of the electroosmotic flow (EOF) changed with the composition of the MLM. As the percent of the monomer ODA in the polymerization mixture was increased, the EOF increased to a maximum at 50‐mol% ODA and then leveled off at 75‐mol% and 100‐mol% ODA, an indication that the ODA ligand in general exhibited a higher binding for the mobile‐phase ions than the NAPM ligand. This is due to the fact that the ODA is an acrylate‐based monomer, whereas the NAPM is a methacrylate‐based monomer. While ODA provided solely nonpolar interactions, NAPM exhibited both nonpolar and π interactions with certain solutes. It was found out that columns with a given composition of both ligands yielded a unique selectivity for a given set of solutes that was not matched by columns made by either ODA or NAPM alone. Several test mixtures were used in the evaluation of the MLM columns including polycyclic aromatic hydrocarbons, alkyl phenyl ketones, nitroalkanes, alkylbenzenes, toluene derivatives, peptides, and proteins. Peptide mapping of the tryptic digest of the standard lysozyme protein was also studied.
IL‐28A (IFN‐λ2) modulates lung DC function to promote Th1 immune skewing and suppress allergic airway disease
Authors: Koltsida Ourania , Hausding Michael , Stavropoulos Athanasios , Koch Sonja , Tzelepis George , Übel Caroline , Kotenko Sergei V. , Sideras Paschalis , Lehr Hans A. , Tepe Marcus , Klucher Kevin M. , Doyle Sean E. , Neurath Markus F. , Finotto Susetta , Andreakos Evangelos
Published: April 2011

IL‐28 (IFN‐λ) cytokines exhibit potent antiviral and antitumor function but their full spectrum of activities remains largely unknown. Recently, IL‐28 cytokine family members were found to be profoundly down‐regulated in allergic asthma. We now reveal a novel role of IL‐28 cytokines in inducing type 1 immunity and protection from allergic airway disease. Treatment of wild‐type mice with recombinant or adenovirally expressed IL‐28A ameliorated allergic airway disease, suppressed Th2 and Th17 responses and induced IFN‐γ. Moreover, abrogation of endogenous IL‐28 cytokine function in IL‐28Rα−/− mice exacerbated allergic airway inflammation by augmenting Th2 and Th17 responses, and IgE levels. Central to IL‐28A immunoregulatory activity was its capacity to modulate lung CD11c+ dendritic cell (DC) function to down‐regulate OX40L, up‐regulate IL‐12p70 and promote Th1 differentiation. Consistently, IL‐28A‐mediated protection was absent in IFN‐γ−/− mice or after IL‐12 neutralization and could be adoptively transferred by IL‐28A‐treated CD11c+ cells. These data demonstrate a critical role of IL‐28 cytokines in controlling T cell responses in vivo through the modulation of lung CD11c+ DC function in experimental allergic asthma.

→See accompanying Closeup by Michael R Edwards and Sebastian L Johnston http://dx.doi.org/10.1002/emmm.201100143