bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbonylation of Nitrobenzene in Methanol with Palladium Bidentate Phosphane Complexes: An Unexpectedly Complex Network of Catalytic Reactions, Centred around a Pd–imido Intermediate
Authors: Mooibroek Tiddo J. , Schoon Lodi , Bouwman Elisabeth , Drent Eite
Published: October 2011

The reactivity of palladium complexes of bidentate diaryl phosphane ligands (P2) was studied in the reaction of nitrobenzene with CO in methanol. Careful analysis of the reaction mixtures revealed that, besides the frequently reported reduction products of nitrobenzene [methyl phenyl carbamate (MPC), N,N′‐diphenylurea (DPU), aniline, azobenzene (Azo) and azoxybenzene (Azoxy)], large quantities of oxidation products of methanol were co‐produced (dimethyl carbonate (DMC), dimethyl oxalate (DMO), methyl formate (MF), H2O, and CO). From these observations, it is concluded that several catalytic processes operate simultaneously, and are coupled via common catalytic intermediates. Starting from a P2Pd0 compound formed in situ, oxidation to a palladium imido compound P2PdIINPh, can be achieved by de‐oxygenation of nitrobenzene 1) with two molecules of CO, 2) with two molecules of CO and the acidic protons of two methanol molecules, or 3) with all four hydrogen atoms of one methanol molecule. Reduction of P2PdIINPh to P2Pd0 makes the overall process catalytic, while at the same time forming Azo(xy), MPC, DPU and aniline. It is proposed that the Pd–imido species is the central key intermediate that can link together all reduction products of nitrobenzene and all oxidation products of methanol in one unified mechanistic scheme. The relative occurrence of the various catalytic processes is shown to be dependent on the characteristics of the catalysts, as imposed by the ligand structure.
Reaction of an Osmium(VI) Nitrido Complex with Cyanide: Formation and Reactivity of an Osmium(III) Hydrogen Cyanamide Complex
Authors: Xiang Jing , Man Wai‐Lun , Yiu Shek‐Man , Peng Shie‐Ming , Lau Tai‐Chu
Published: October 2011

Reaction of [OsVI(N)(L1)(Cl)(OH2)] (1) with CN− under various conditions affords (PPh4)[OsVI(N)(L1)(CN)(Cl)] (2), (PPh4)2[OsVI(N)(L2)(CN)2] (3), and a novel hydrogen cyanamido complex, (PPh4)2[OsIII{N(H)CN}(L3)(CN)3] (4). Compound 4 reacts readily with both electrophiles and nucleophiles. Protonation and methylation of 4 produce (PPh4)[OsIII(NCNH2)(L3)(CN)3] (5) and (PPh4)[OsIII(NCNMe2)(L3)(CN)3] (6), respectively. Nucleophilic addition of NH3, ethylamine, and diethylamine readily occur at the C atom of the hydrogen cyanamide ligand of 4 to produce osmium guanidine complexes with the general formula [OsIII{N(H)C(NH2)NR1R2}(L3)(CN)3]−, which have been isolated as PPh4 salts (R1=R2=H (7); R1=H, R2=CH2CH3 (8); R1=R2=CH2CH3 (9)). The molecular structures of 1–5 and 7 and 8 have been determined by X‐ray crystallography.
Design of Dinuclear Copper Species with Carboranylcarboxylate Ligands: Study of Their Steric and Electronic Effects
Authors: Fontanet Mònica , Popescu Adrian‐Radu , Fontrodona Xavier , Rodríguez Montserrat , Romero Isabel , Teixidor Francesc , Viñas Clara , Aliaga‐Alcalde Núria , Ruiz Eliseo
Published: October 2011

A series of new mononuclear and carboranylcarboxylate‐bridged dinuclear copper(II) compounds containing the 1‐CH3‐2‐CO2H‐1,2‐closo‐C2B10H10carborane ligand (LH) has been synthesized. Reaction of different copper salts withLH at room temperature leads to dinuclear compounds of the general formula [Cu2(μ‐L)4(Lt)2] (Lt=thf (1),Lt=H2O (1′)). The reaction of1and1′with different terminal pyridyl (py) ligands leads to the formation of a series of structurally analogous complexes by substitution of the terminal ligand thf or H2O (Lt=py (2),p‐CF3‐py (3),p‐CH3‐py (4), pz (6), and 4,4′‐bpy (7)), which maintain the structural Cu2(μ‐O2CR)4core in the majority of the cases except foro‐(CH3)2‐py, where a mononuclear compound (5) is exclusively obtained. These compounds have been characterized through analytical, spectroscopic (NMR, IR, UV‐visible, ESI‐MS) and magnetic techniques. X‐ray structural analysis revealed a paddle‐wheel structure for the dinuclear compounds, with a square‐pyramidal geometry around each copper ion and the carboranylcarboxylate ions bridging two copper atoms insyn–synmode. The mononuclear complex obtained with theo‐(CH3)2‐py ligand presents a square‐planar structure, in which the carboranylcarboxylate ligand adopts a monodentate coordination mode. The magnetic properties of the dinuclear compounds1,3,4, and6show a strong antiferromagnetic coupling in all cases (J=−261 (1), −255 (3), −241 (4), −249 cm−1(6)). Computational studies based on hybrid density functional methods have been used to study the magnetic properties of the complexes and also to evaluate their relative stability on the basis of the strength of the bond between each CuIIand the terminal ligand.
Total Synthesis, Stereochemical Assignment, and Antimalarial Activity of Gallinamide A
Authors: Conroy Trent , Guo Jin T. , Linington Roger G. , Hunt Nicholas H. , Payne Richard J.
Published: October 2011

The total synthesis and stereochemical assignment of gallinamide A, an antimalarial depsipeptide of cyanobacterial origin, is described. Synthesis of the four possible N‐terminal diastereoisomers of gallinamide A (including the natural product symplostatin 4) was achieved using a divergent strategy from a common imide fragment. The natural product and corresponding diastereoisomers were synthesized in 30–33 % overall yield in a longest linear sequence of 8 steps. Comparative NMR spectroscopic studies of the four synthetic diastereoisomers with the isolated natural product demonstrated that gallinamide A possesses a dimethylated L‐isoleucyl residue at the N‐terminus. As such, we have shown that gallinamide A is structurally and stereochemically identical to symplostatin 4. Gallinamide A and its N‐terminal diastereoisomers were also shown to possess significant antimalarial activity with IC50 values in the nanomolar range against the 3D7 strain of Plasmodium falciparum.
ChemInform Abstract: A Novel Recyclable Organocatalytic System for the Highly Asymmetric Michael Addition of Aldehydes to Nitroolefins in Water.
Authors: Sarkar Dhruba , Bhattarai Ramesh , Headley Allan D. , Ni Bukuo
Published: October 2011

The products are formed in an enantiopure form with excellent diastereoselectivity.
ChemInform Abstract: Synthesis, Characterization and Antimicrobial Activity of Some 3‐(2‐(1H‐Benzo[d]imidazol‐2‐yl)phenyl)‐2‐arylthiazolidin‐4‐ones.
Authors: Desai N. C. , Bhatt Nayan , Kumar Mukesh , Makwana Atul
Published: October 2011

12 Title compounds of type (VII) are prepared and their antibacterial and antifungal activities are investigated.
Performance Enhancement of Solar Latent Heat Thermal Storage System with Particle Dispersion — an Exergy Approach
Authors: Jegadheeswaran Selvaraj , Pohekar Sanjay D. , Kousksou Tarik
Published: October 2011

Phase change material (PCM) employed latent heat thermal storage (LHTS) system has been showing good potential over the years for energy management, particularly in solar energy systems. However, enhancement in thermal conductivity of PCMs is emphasized as PCMs are known for their poor thermal conductivity. In this work, the thermal performance of a shell and tube LHTS module containing PCM‐metal particles composite is investigated while charging and is compared with that of pure PCM system. The effect of particle dispersion on latent heat capacity of pure PCM is also analyzed. Enthalpy based governing equations are solved numerically adopting FLUENT code. Exergy based performance evaluation is taken as a main aspect. The numerical results are presented for various operating conditions of heat transfer fluid (HTF) and indicate considerable performance improvement of the system when particles are dispersed.
Application‐specific thread schedulers for internet server applications
Authors: Roper Matthew D. , Olsson Ronald A.
Published: October 2011

This paper describes CATAPULTS (Creating And Testing APplication‐specific User Level Thread Schedulers), a domain‐specific language for creating and testing application‐specific user‐level thread schedulers. Using a domain‐specific language to write user‐level thread schedulers provides three advantages. First, doing so modularizes the thread scheduler, making it easy to plug in and experiment with different thread scheduling strategies. Second, using a domain‐specific language for scheduling code helps prevent several of the common programming mistakes that are easy to make when developing thread schedulers. Finally, the CATAPULTS translator has multiple backends that generate code for different languages and libraries. This makes it easy to prototype an application in a high‐level language and then later port it to a low‐level language; the CATAPULTS translator will take care of generating the appropriate code for both the prototype and the final version of the program from a single scheduler specification. This paper describes how we have used CATAPULTS to improve the performance of two important and representative Internet server applications. Copyright © 2011 John Wiley & Sons, Ltd.
Carbon Nanoparticles as Chromophores for Photon Harvesting and Photoconversion
Authors: Xu Juan , Sahu Sushant , Cao Li , Anilkumar Parambath , Tackett Kenneth N. , Qian Haijun , Bunker Christopher E. , Guliants Elena A. , Parenzan Alexander , Sun Ya‐Ping
Published: October 2011

Carbon nanomaterials have generated a tremendous amount of attention in the scientific community. While most of the research and development efforts have been on fullerenes, carbon nanotubes, and graphene sheets, carbon nanoparticles (which are often considered as impurities or unwanted complications in the other carbon nanomaterials) have recently emerged as a unique class of highly fluorescent nano‐dots. However, little or no attention has been paid to potential uses of carbon nanoparticles as chromophores in photochemical reactions or for photon harvesting and photoconversion in general. In the study reported herein we demonstrate the chromophore‐equivalent functions of aqueous‐suspended small carbon nanoparticles in harvesting visible photons for the reductive coating of the nanoparticles with silver and gold and, as a result, the preparation of unique carbon–noble‐metal core–shell nanostructures.
Growth and characterization of isotopically enriched 40Ca100MoO4 single crystals for rare event search experiments
Authors: Alenkov V. V. , Buzanov O. A. , Khanbekov N. , Kim S. K. , Kim H. J. , Kornoukhov V. N. , Kraus H. , Mikhailik V. B.
Published: October 2011

Calcium molybdate is considered as a very promising scintillator material for experimental studies of rare processes. This paper reports on the production and characterization of a 40Ca100MoO4 scintillator. Using the Czochralski technique, a crystal of high optical quality with total mass 0.55 kg, 42 mm diameter (minimum) and 53 mm 1ength of the cylindrical section was produced from isotopically enriched raw materials, containing 96.1% of 100Mo and 99.964% of 40Ca. To satisfy the requirement of low intrinsic radioactivity the purity of the materials was monitored at different stages of the production process and it is shown that the concentration of 238U and 232Th in the final crystal does not exceed 0.05 ppb. The scintillation properties of 40Ca100MoO4 were measured over the 8 – 300 K temperature range and it is found that the light yield of the 40Ca100MoO4 crystal is very similar to that of the CaMoO4 reference scintillator. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sampled‐data poles, zeros, and modeling for current‐mode control
Authors: Fang Chung‐Chieh
Published: October 2011

Exact and approximate sampled‐data models in closed forms are derived for switching DC–DC converters under peak/valley current‐mode control. The corresponding sampled‐data poles and zeros in closed forms are also derived. The location and stability conditions of the poles and zeros, boundary conditions of subharmonic instability, and nulling of the audio‐susceptibility are also derived. It is proved that the stable operating range of the source voltage is linearly proportional to the ramp slope. The sampled‐data models agree with previous experiment results and accurately predict the subharmonic instability. The different view from the sampled‐data model about the number and stability (minimum phase) of pole and zero does not necessarily invalidate the traditional continuous‐time averaged model. However, this different view gives better prediction about converter dynamics and is useful for the analog or digital controller design for DC–DC converters. Copyright © 2011 John Wiley & Sons, Ltd.
Implementation of an interleaved pulse‐width modulation converter for renewable energy conversion
Authors: Lin Bor‐Ren , Chao Chia‐Hung , Chiang Yen‐Ju
Published: October 2011

This paper presents an interleaved soft switching converter to achieve the features of zero voltage switching (ZVS) turn‐on for power switches, zero current switching turn‐off for rectifier diodes at full load, less transformer secondary winding with full‐wave diode rectifier topology, and balance primary currents with series connection of the transformer secondary windings. Two circuit modules are adopted in the proposed circuit, and they are operated with an interleaved pulse‐width modulation. Thus, ripple currents at the input and output sides are reduced. In each module, two ZVS converters using the same switches are operated with interleaved half switching cycle. The secondary windings of transformers are connected in series in order to ensure that the primary side currents are balanced. The full‐wave diode rectifier topology is used on the output side such that the voltage stress of rectifier diodes equals output voltage, rather than being two times the output voltage as in a conventional center‐tapped rectifier topology. Laboratory experiments with a 1000‐W prototype are provided to describe the effectiveness of the proposed converter. Copyright © 2011 John Wiley & Sons, Ltd.
A simple and sensitive GC/MS method for the determination of atropine during therapy of anticholinesterase poisoning in serum samples
Authors: Papoutsis Ioannis , Nikolaou Panagiota , Spiliopoulou Chara , Pistos Constantinos , Stefanidou Maria , Athanaselis Sotirios
Published: October 2011

Atropine is used in the daily clinical practice for the treatment of poisonings caused by anticholinesterase pesticides, due to its sympathomimetic action. The investigation of the cause of the adverse effects that appear during atropine administration showed the necessity for the development and validation of a simple, rapid, sensitive, and specific method for the determination of atropine levels in serum samples. The developed method includes liquid‐liquid extraction with ethyl acetate: dichloromethane (3:1, v/v) and derivatization using N,O‐bis(trimethylsilyl)‐trifluoracetamide (BSTFA) with 1% trimethylchlorsilane (TMCS) in acetonitrile environment. The method was found to be selective, linear, accurate, and precise according to international guidelines. The recovery was higher than 85.9%, the limit of quantification was 2.00 ng/ml, and the calibration curve was linear within the range of 2.00–500 ng/ml (R2 ≥ 0.992). Accuracy and precision were also calculated and were found to be less than 5.2 and 8.7%, respectively. The developed method was applied in a real case of accidental poisoning with chlorpyrifos in order to determine the atropine serum levels of the patient. The proposed method proved to be useful for the investigation of adverse effects that appear during atropine treatment of patients poisoned by anticholinesterase pesticides and it can also be used for the investigation of poisonings caused after consumption of atropine containing plants. Copyright © 2011 John Wiley & Sons, Ltd.
Identification of fibroblast growth factor 1 (FGF‐1) in a black market product
Authors: Walpurgis Katja , Thomas Andreas , Laussmann Tim , Horta Luis , Metzger Sabine , Schänzer Wilhelm , Thevis Mario
Published: October 2011

The use of growth factors for accelerated healing of sports injuries is restricted under the terms of the World Anti‐Doping Agency (WADA) anti‐doping code. Cheating athletes have used the black market as a source of performance‐enhancing substances. Drugs that currently undergo clinical trials are frequently offered – despite the unknown health risks associated with the administration of unapproved pharmaceuticals. Recently, a new growth factor (referred to as fibroblast growth factor 1/FGF‐1) with known effects on the repair and regeneration of damaged tissue was detected in an unlabelled black market product confiscated by the German customs. The identification of the protein was achieved by one‐ and two‐dimensional polyacrylamide gel electrophoresis (SDS‐PAGE and 2D‐PAGE), different proteolytic digestions, immunological methods and nano‐liquid chromatography high‐resolution/high‐accuracy Orbitrap mass spectrometry. The SDS‐PAGE analysis revealed slight differences concerning the molecular weight of recombinant human and black market FGF‐1. Using in‐gel proteolysis, a truncation or modification located at the N‐terminus of the protein was suggested. These findings demonstrate that drug candidates without clinical approval can be readily obtained from the black market, regardless of potential dangerous consequences for the consumer, which corroborates the necessity of proactive and preventive doping control approaches. In that regard, physiological concentrations of blood and urine specimens collected from healthy individuals were analyzed and were found to range below 28 pg/ml in urine, while there was no detectable FGF‐1 in plasma. Copyright © 2011 John Wiley & Sons, Ltd.
The Notch‐regulated ankyrin repeat protein is required for proper anterior–posterior somite patterning in mice
Authors: Krebs Luke T. , Bradley Cara K. , Norton Christine R. , Xu Jingxia , Oram Kathleen F. , Starling Christa , Deftos Michael L. , Bevan Michael J. , Gridley Thomas
Published: October 2011

The Notch‐regulated ankyrin repeat protein (Nrarp) is a component of a negative feedback system that attenuates Notch pathway‐mediated signaling. In vertebrates, the timing and spacing of formation of the mesodermal somites are controlled by a molecular oscillator termed the segmentation clock. Somites are also patterned along the rostral‐caudal axis of the embryo. Here, we demonstrate that Nrarp‐deficient embryos and mice exhibit genetic background‐dependent defects of the axial skeleton. While progression of the segmentation clock occurred in Nrarp‐deficient embryos, they exhibited altered rostrocaudal patterning of the somites. In Nrarp mutant embryos, the posterior somite compartment was expanded. These studies confirm an anticipated, but previously undocumented role for the Nrarp gene in vertebrate somite patterning and provide an example of the strong influence that genetic background plays on the phenotypes exhibited by mutant mice. genesis 50:366–374, 2012. © 2011 Wiley Periodicals, Inc.
Sometimes stories sell: When are narrative appeals most likely to work?
Authors: Thompson Rose , Haddock Geoffrey
Published: October 2011

Research has demonstrated that narratives can be effective in eliciting attitude change, especially when recipients become transported into the narrative. In three studies, we addressed whether some people are predisposed to be influenced by narratives and whether narrative and rhetorical appeals are differentially effective for different people. In Study 1, participants read an experimental or a control narrative, and completed measures of attitudes, need for affect (NFA), need for cognition (NFC), transportation, and transportability. The results revealed that NFA and NFC were positively correlated with transportation and transportability. In Study 2, participants read either a narrative appeal or a rhetorical appeal about cervical cancer and completed a measure of attitudes and the individual difference constructs. Study 3 was a replication of Study 2 using a different topic (organ donation). In both studies, the results revealed a consistent pattern of correlations among the individual difference measures. Further, we found that although the narrative and rhetorical appeals were judged to be of equal efficacy, the persuasiveness of the narrative appeal differed as function of individual differences in NFA and NFC. The implications for narrative persuasion are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Persistence of attitude change and attitude–behavior correspondence based on extensive processing of source information
Authors: Pierro Antonio , Mannetti Lucia , Kruglanski Arie W. , Klein Kristen , Orehek Edward
Published: October 2011

A three‐phase longitudinal study (spread over a month's time) was carried out to investigate attitude's persistence and linkage to behavior as it may be affected by the processing of information about the communication source. The following three independent variables were manipulated: (i) contents of the source of information (implying the communicator to be expert or inexpert on the topic of the communication); (ii) length of the source information (brief versus lengthy); and (iii) message recipients' involvement in the issue at hand (high versus low). Replicating prior research when the source information was brief, it exerted greater persuasive impact under low versus high involvement, and when it was lengthy, it exerted greater persuasive impact under high versus low involvement. Of greater importance, the newly acquired attitudes were more persistent and were linked more strongly to actual behavior when the source information was lengthy (versus brief) provided the recipients had high (versus low) involvement in the issue. These findings were interpreted to mean that just like with the message/issue information in prior research, when processed extensively, source information, too, may contribute to the formation of persistent and behavior‐driving attitudes. Copyright © 2011 John Wiley & Sons, Ltd.
Towards Ion‐Selective Membranes with Electrogenerated Chemiluminescence Detection: Visualizing Selective Ru(bpy)32+ Transport Across a Plasticized Poly(vinyl chloride) Membrane
Authors: Crespo Gastón A. , Mistlberger Günter , Bakker Eric
Published: October 2011

We report here on an attractive concept to integrate electrochemically triggered ion‐selective transport across an ion‐selective plasticized PVC membrane and electrogenerated chemiluminescence (ECL) as a detection technique. This will eventually form the basis for an alternate transduction mechanism for electrochemical ion sensors. To this end, the selective extraction of the ECL reagent Ru(bpy)32+ is demonstrated by an o‐NPOE plasticized PVC membrane doped with lipophilic cation‐exchanger. Chemical imaging of Ru(bpy)32+ electrotransported across the PVC membrane demonstrates the feasibility of this concept as a future trend for two dimensional ion sensing.
Preparative‐scale isoelectric trapping by recursive electrophoresis in a compartmentalized system having orthogonal primary and secondary pH gradients. Part 2 – Operation in cascade mode
Authors: North Robert Y. , Vigh Gyula
Published: October 2011

A parallel multicompartmental electrolyzer recently developed for preparative‐scale isoelectric trapping separations, trapping by recursive electrophoresis in a compartmentalized system, was set up to operate as a cascade of binary separations to produce at least one pure target ampholyte (or more, with additional separation heads) without other ampholytes ever entering (even transiently) the harvest stream. This mode of operation avoids the need for exhaustive electrophoresis and the accompanying long separation times brought about by the exponentially decreasing concentrations over the course of batch separations. Continuous operation can be achieved in the cascade mode by continuously feeding the sample into the first separation head configured with three flow‐through compartments and continuously harvesting one (or more) target components in additional separation heads configured with two flow‐through compartments, attached to the respective branching points.
Capillary electrophoresis with LIF detection for assessment of mitochondrial number based on the cardiolipin content
Authors: Zhao Wenfeng , Chen Qidan , Wu Ruige , Wu Hong , Fung Yingsing , O Waisum
Published: October 2011

Cardiolipin is a mitochondria‐specific phospholipid known to be intimately involved with numerous mitochondrial functions. Accordingly, quantitative determination of cardiolipin provides a valuable aspect for assessing mitochondrial content and function. The current study was undertaken to develop a simple and reliable method for direct analysis of cardiolipin with particular application for the assessment of mitochondrial number of HepG2 cells. The method presented is based on the online 10‐N‐nonyl acridine orange (NAO) interaction with cardiolipin using CE with LIF detection. An aqueous‐organic solvent system composed of 10% H2O–40% methanol–50% ACN (all v/v) containing 20 μM NAO provides both short analysis time within 2 min and a definite fluorescence enhancement at 525 nm for NAO–cardiolipin complex as compared with NAO alone. Under the optimum condition, a calibration curve between the peak area and the concentration of cardiolipin was established in the range of 0.1–200 μM with a correlation coefficient of 0.9955. The detection limit is 9 nM. The proposed method was successfully applied to the analysis of cardiolipin in mitochondria from HepG2 cells. A new biochemical method estimating the mitochondrial number per cell was developed and used together with the proposed method for cardiolipin per cell measurement and cardiolipin per mitochondrion reported before.
Biomass energy with carbon capture and storage (BECCS or Bio‐CCS)
Authors: Gough Clair , Upham Paul
Published: October 2011

In terms of climate mitigation options, the theoretical potential of biomass energy with carbon capture and storage (BECCS) is substantial; introducing the prospect of negative emissions, it offers the vision of drawing atmospheric CO2 concentrations back down to pre‐industrial levels. This paper reviews issues raised at a workshop on BECCS, convened in Scotland in late 2009. Presentations by bioenergy and CCS specialists covered topics including the climate policy rationale for BECCS, global biomass CCS potential, the UK potential for BECCS, the risk of fossil fuel lock‐in via coal co‐firing, and carbon market issues. In practice, the scale of the forestry and accessible CCS infrastructure required are among the obstacles to the large‐scale deployment of BECCS in the near term. While biomass co‐firing with coal offers an early route to BECCS, a quite substantial (>20%) biomass component may be necessary to achieve negative emissions in a co‐fired CCS system. Smaller scale BECCS, through co‐location of dedicated or co‐combusted biomass on fossil CCS CO2 transport pipeline routes, is easier to envisage and would be potentially less problematic. Hence, we judge that BECCS can, and likely will, play a role in carbon reduction, but care needs to be taken not to exaggerate its potential, given that (i) there are few studies of the cost of connecting bio‐processing (combustion, gasification or other) infrastructure with CO2 storage sites and (ii) that scenarios of global bioenergy potential remain contentious. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Intentional social distance regulation alters affective responses towards victims of violence: An FMRI study
Authors: Leiberg Susanne , Eippert Falk , Veit Ralf , Anders Silke
Published: October 2011

We used functional magnetic resonance imaging (fMRI) to investigate brain processes underlying control of emotional responses towards a person in distress by cognitive social distance modulation. fMRI and peripheral physiological responses (startle response and electrodermal activity) were recorded from 24 women while they watched victim–offender scenes and modulated their social distance to the victim by cognitive reappraisal. We found that emotional responses, including startle eyeblink and amygdala responses, can effectively be modulated by social distance modulation. Furthermore, our data provide evidence that activity in the dorsomedial prefrontal cortex (dmPFC) and the anterior paracingulate cortex (aPCC), two brain regions that have previously been associated with brain processes related to distant and close others, is differentially modulated by intentional social distance modulation: activity in the dmPFC increased with increasing disengagement from the victim and activity in the aPCC increased with increasing engagement with the victim. We suggest that these two regions play opposing roles in cognitive modulation of social distance and affective responses towards persons in distress that enable the adaptive and flexible social behavior observed in humans. Hum Brain Mapp 33:2464–2476, 2012. © 2011 Wiley Periodicals, Inc.
Synthesis of new racemic and optically active N‐phosphonoalkyl bicyclic β‐amino acids via the kabachnik–fields reaction as potential biologically active compounds
Authors: Todorov Petar T. , Pavlov Nikola D. , Shivachev Boris L. , Petrova Rosica N. , Martinez Jean , Naydenova Emilia D. , Calmes Monique
Published: October 2011

Novel racemic and optically active constrained N‐phosphonoalkyl bicyclic β‐amino acids have been synthesized via the Kabachnik–Fields reaction of the (RS) or (R)‐1‐aminobicyclo[2.2.2]octane‐2‐carboxylic acids with paraformaldehyde and benzaldehyde, and the dimethyl‐H‐phosphonate. The structure of obtained compounds was characterized by NMR (1H, 13C, and 31P), LC/MS, and X‐ray diffraction analyses. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:123–130, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20759
Aberrant hippocampal spine morphology and impaired memory formation in neuronal platelet‐derived growth factor beta‐receptor lacking mice
Authors: Shioda Norifumi , Moriguchi Shigeki , Oya Takeshi , Ishii Yoko , Shen Jie , Matsushima Takako , Nishijo Hisao , Sasahara Masakiyo , Fukunaga Kohji
Published: October 2011

The physiological role of platelet‐derived growth factor (PDGF) in the central nervous system (CNS) synaptic function remains uncharacterized. Here we identify physiological roles of PDGF receptor‐β (PDGFR‐β) in the CNS by conditional knockout of the gene encoding it. In the hippocampus, PDGFR‐β colocalized immunohistochemically with both presynaptic synaptophysin and postsynaptic density‐95 (PSD‐95). In the hippocampal CA1 region, expression levels of postsynaptic proteins, including spinophilin, drebrin, and PSD‐95, were significantly decreased in PDGFR‐β knockout mice, although presynaptic synaptophysin levels remained comparable to controls. Interestingly, in hippocampal CA1 pyramidal neurons, dendritic spine density in PDGFR‐β knockout mice was significantly decreased compared with that seen in wild‐type mice, although spine length and number of dendritic branches remained unchanged. Consistent with these findings, impairment in hippocampal long‐term potentiation (LTP) and in hippocampus‐dependent memory formation were seen in PDGFR‐β knockout mice. These results suggest PDGFR‐β plays critical roles in spine morphology and memory formation in mouse brain. © 2011 Wiley Periodicals, Inc.
BOSC: A better oscillation detection method, extracts both sustained and transient rhythms from rat hippocampal recordings
Authors: Hughes Adam M. , Whitten Tara A. , Caplan Jeremy B. , Dickson Clayton T.
Published: October 2011

Neuronal population oscillations at a variety of frequencies can be readily seen in electroencephalographic (EEG) as well as local field potential recordings in many different species. Although these brain rhythms have been studied for many years, the methods for identifying discrete oscillatory epochs are still widely variable across studies. The “better oscillation detection” (BOSC) method applies standardized criteria to detect runs of “true” oscillatory activity and rejects transient events that do not reflect actual rhythms. It does so by estimating the background spectrum of the actual signal to derive detection criteria that include both power and duration thresholds. This method has not yet been applied to nonhuman data. Here, we test the BOSC method on two important rat hippocampal oscillatory signals, the theta rhythm and slow oscillation (SO), two large amplitude and mutually exclusive states. The BOSC method detected both the relatively sustained theta rhythm and the relatively transient SO apparent under urethane anesthesia and was relatively resilient to spectral features that changed across states, complementing previous findings for human EEG. Detection of oscillatory activity using the BOSC method (but not more traditional Fourier transform‐based power analysis) corresponded well with human expert ratings. Moreover, for near‐continuous theta, BOSC proved useful for detecting discrete disruptions that were associated with sudden and large amplitude phase shifts of the ongoing rhythm. Thus, the BOSC method accurately extracts oscillatory and nonoscillatory episodes from field potential recordings and produces systematic, objective, and consistent results—not only across frequencies, brain regions, tasks, and waking states, as shown previously, but also across species and for both sustained and transient rhythms. Thus, the BOSC method will facilitate more direct comparisons of oscillatory brain activity across all types of experimental paradigms. © 2011 Wiley Periodicals, Inc.
Reaction of N‐(phenyl and methyl)‐C‐arylnitrones with DMAD in ionic liquid: Efficient synthesis of Δ4‐isoxazolines
Authors: Valizadeh Hassan , Vesally Esmail , Dinparast Leila
Published: October 2011

Facile synthesis of N‐(methyl and phenyl)‐Δ4‐isoxazolines via the reaction of (Z)‐N‐(methyl and phenyl)‐C‐arylnitrones with dimethyl acethylenedicarboxylate, DMAD, in ionic liquid is described. (Z)‐N‐methyl‐C‐arylnitrones afforded the high yield of N‐methyl‐Δ4‐isoxazolines 4a, 4b, 4c, 4d, 4e in ionic liquid, [bmim]BF4, at room temperature. However, the reaction of (Z)‐N‐phenyl‐C‐arylnitrones with DMAD afforded the mixtures of cis and trans isomers of related N‐phenyl‐Δ4‐isoxazolines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) under these conditions. J. Heterocyclic Chem., (2012).
MCM‐41‐SO3H as a nanoreactor for the one‐pot, solvent‐free synthesis of 1,8‐dioxo‐9‐aryl decahydroacridines
Authors: Rostamizadeh Shahnaz , Amirahmadi Asiyeh , Shadjou Nasrin , Amani Ali M.
Published: October 2011

One‐pot four‐component synthesis of 1,8‐dioxo‐9‐aryl decahydroacridines in solvent‐free condition was efficiently performed in the presence of MCM‐41‐SO3H as a nanocatalyst and nanoreactor in good yields. The method provides several advantages such as low cost, operational and experimental simplicity, high yields, and short reaction times. J. Heterocyclic Chem., (2012).
Synthesis of a delta opioid agonist in [2H6], [2H4], [11C], and [14C] labeled forms
Authors: Elmore Charles S. , Brush Kelly , Schou Magnus , Palmer William , Dorff Peter N. , Powell Mark E. , Hoesch Valerie , Hall James E. , Hudzik Thomas , Halldin Christer , Dantzman Cathy L.
Published: October 2011

In support of a program to develop a treatment for depression, four labeled forms of a delta opioid agonist were prepared. The [2H4] labeled form was prepared using a relatively straightforward conversion of [2H4]bromoethanol to [2H4]N‐methyl‐2‐hydroxyethylamine. The key step in the synthesis of the [2H6] labeled form involved the Pd‐catalyzed exchange in D2O of 8‐quinolin‐8‐ol to give [2H6] 8‐quinolin‐8‐ol. The C‐14 labeled form was synthesized in one step using [14C]carbonylation, and the C‐11 labeled form was prepared in two steps from 11CH3I. Copyright © 2011 John Wiley & Sons, Ltd.
Cyclic peptide as reference system for b ion structural analysis in the gas phase
Authors: Chen Xian , Tirado Marcus , Steill Jeffrey D. , Oomens Jos , Polfer Nick C.
Published: October 2011

Infrared multiple photon dissociation spectroscopy and hydrogen/deuterium exchange methods are used to confirm the macrocylic structure of a b6 peptide fragment by direct comparison with a synthetically made cyclic peptide. The acetylation of the peptide N‐terminus results in the inhibition of the macrocyclic formation, supporting the “head‐to‐tail” cyclization mechanism. Differences in hydrogen/deuterium exchange rates for macrocyclic and oxazalone structure peptide fragments are interpreted to be a result of the complex interplay of multiple basic sites in the peptide fragment, supporting the relay mechanism for deuterium exchange with CH3OD. Copyright © 2011 John Wiley & Sons, Ltd.
Mass spectrometric characterization of peptides containing different oxidized tryptophan residues
Authors: Todorovski Toni , Fedorova Maria , Hoffmann Ralf
Published: October 2011

The term reactive oxygen species refers to small molecules that can oxidize, for example, nearby proteins, especially cysteine, methionine, tryptophan, and tyrosine residues. Tryptophan oxidation is always irreversible in the cell and can yield several oxidation products, such as 5‐hydroxy‐tryptophan (5‐HTP), oxindolylalanine (Oia), kynurenine (Kyn), and N‐formyl‐kynurenine (NFK). Because of the severe effects that oxidized tryptophan residues can have on proteins, there is a great need to develop generally applicable and highly sensitive techniques to identify the oxidized residue and the oxidation product. Here, the fragmentation behavior of synthetic peptides corresponding to sequences recently identified in three skeletal muscle proteins as containing oxidized tryptophan residues were studied using postsource decay and collision‐induced dissociation (CID) in matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF)/TOF mass spectrometry (MS) and CID in an electrospray ionization (ESI) double quadrupole TOF‐MS. For each sequence, a panel of five different peptides containing Trp, 5‐HTP, Kyn, NFK, or Oia residue was studied. It was always possible to identify the modified positions by the y‐series and also to distinguish the different oxidation products by characteristic fragment ions in the lower mass range by tandem MS. NFK‐ and Kyn‐containing peptides displayed an intense signal at m/z 174.1, which could be useful in identifying accordingly modified peptides by a sensitive precursor ion scan. Most importantly, it was always possible to distinguish isomeric 5‐HTP and Oia residues. In ESI‐ and MALDI‐MS/MS, this was achieved by the signal intensity ratios of two signals obtained at m/z 130.1 and 146.1. In addition, high collision energy CID in the MALDI‐TOF/TOF‐MS also permitted the identification of these two isomeric residues by their v‐ and w‐ions, respectively. Copyright © 2011 John Wiley & Sons, Ltd.
The Integrated Deconvolution Estimation Model: Estimation of Reactivity Ratios per Site Type for Ethylene/1‐Butene Copolymers Made with a Heterogeneous Ziegler‐Natta Catalyst
Authors: Al‐Saleh Mohammad A. , Soares João B. P. , Duever Thomas A.
Published: October 2011

The integrated deconvolution estimation model (IDEM) can be used to estimate the reactivity ratios of multiple‐site‐type catalysts used to make ethylene/α‐olefin copolymers, such as heterogeneous Ziegler‐Natta and Phillips catalysts. The estimation process combines high‐temperature GPC and 13C NMR data to find the reactivity ratios per site type. The IDEM is applied to two sets of ethylene/1‐butene copolymer samples made with an industrial TiCl4/MgCl2 catalyst in the presence and absence of hydrogen. A sensitivity analysis for parameter estimation is developed and the effect of the presence of hydrogen on the reactivity ratio per site type is quantified for the first time for this copolymerization system.

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A stabilization algorithm of the Navier–Stokes equations based on algebraic Bernoulli equation
Authors: Amodei L. , Buchot J.‐M.
Published: October 2011

In this paper, we consider the stabilization of the nonstationary incompressible Navier–Stokes equations around a stationary solution by a boundary linear feedback control. The feedback operator is obtained from the solution of the algebraic Bernoulli equation associated with the penalized linearized Navier–Stokes equations around an unstable stationary solution and is used to locally stabilize the original nonlinear equations. We give the explicit factorized form of the stabilizing solution of the algebraic Bernoulli equation. The numerical effectiveness of this approach is demonstrated by stabilizing the vortex shedding behind a circular obstacle. Copyright © 2011 John Wiley & Sons, Ltd.
A local thermomechanical model of friction for computing structures under extreme loading conditions
Authors: Dambakizi F. , Le Tallec P. , Perlat J. P.
Published: October 2011

A multiscale thermomechanical model of friction is proposed for metallic interfaces submitted to extreme loading conditions with large sliding velocities ( [v] > 100 ms−1) and high contact pressures (P > 1 GPa). This model decomposes the friction problem into a global multidimensional structural problem and a local interface subproblem. At global scale, the structure behavior is governed by an elastoplastic model in large strains, and thermal conduction is neglected. The local model describes the micrometric scale and the underlying thermomechanical mechanisms: mechanical hardening, frictional heating, and plastic work. Using dimensional and asymptotic analysis, the corresponding set of equations at local scale is simplified and reduces to a one‐dimensional quasistatic thermoelastoplastic friction model. It is solved locally at each global point by a finite differences subgrid model using a nonlinear time‐implicit solver. This solver is coupled to a time‐explicit Lagrangian hydrocode used at the global structural scale. The coupling strategy between the solvers is force‐based: the frictional stress is evaluated at the local scale by our multiscale friction model and transferred to the global model that can then predict local velocity corrections. This coupling strategy has been successfully tested on real‐life cases. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of surface treatments of banana fiber on mechanical, thermal, and biodegradability properties of PLA/banana fiber biocomposites
Authors: Jandas P.J. , Mohanty S. , Nayak S.K. , Srivastava H.
Published: October 2011

Poly lactic acid (PLA)/Banana fiber (BF) biocomposites were fabricated employing melt blending technique followed by compression molding. BF were surface‐treated by NaOH and various silanes viz. 3‐aminopropyltriethoxysilane (APS) and bis‐(3‐triethoxy silyl propyl) tetrasulfane (Si69) to improve the compatibility of the fibers within the matrix polymer. Mechanical tests revealed an increase of tensile strength to the tune 136% and impact strength to 49% as compared with the untreated biocomposite. Thermal properties of the composites have been evaluated using DSC and TGA. DSC thermograms revealed an increase in the melting transitions thus revealing effective fiber/matrix interface. The thermal stability in the biocomposites also increased in case of banana fiber treated with Si69. Viscoelastic measurements using DMA confirmed an increase of storage modulus and low damping values in the silane treated biocomposites. Biodegradation studies in the biocomposites have been investigated in B. cepacia medium through morphological and weight loss studies. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Eco‐friendly separation of catechins using cyclodextrins as mobile phase additives in RP‐HPLC
Authors: Bi Wentao , Li Shengnan , Row Kyung Ho
Published: October 2011

Background

New mobile phases for RP‐HPLC were developed for the separation of catechin compounds in tea. Cyclodextrin mobile phase additives decreased the use of toxic and inflammable organic solvents without compromising resolution or separation efficiency.

Aims

To develop a simple greener method for analyzing five tea catechins in RP‐HPLC, the mobile phase condition was optimized and the lowest organic modifier proportion with content resolutions and retention factors were obtained.

Materials & Methods

– Eco‐friendly cyclodextrins were used as mobile phase additives to decrease the proportion of organic modifier and improve resolutions and retention factors.

Results

The effects of several physico‐chemical parameters on the retention factors were investigate d and the optimum conditions were obtained on a conventional C18 column, where the mobile phase consisted of acetonitrile/water (12/88, v/v) with 1.5 mmol/L β‐cyclodextrin at a flow rate of 1.0 mL/min.

Discussion

Cyclodextrins can separate analytes through host‐guest complexation, where a transient diastereomeric complex is formed between the cyclodextrin and the analyte. β‐Cyclodextrin is the most accessible, the least expensive and generally the most useful cyclodextrin.

Conclusion

This work developed a simple eco‐friendly method with the lowest concentration of organic solvents. Under the optimal condition, five catechins could be baseline separated within 17 minutes in the isocratic mode. This research exhibited the potential for the separation and determination of other active compounds from natural plants by a greener method. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative and Transformation Product Analysis of Major Active Physalins from Physalis Alkekengi Var. Franchetii (Chinese Lantern) Using Ultraperformance Liquid Chromatography with Electrospray Ionisation Tandem Mass Spectrometry and Time‐of‐flight Mass Spectrometry
Authors: Zheng Yunliang , Chen Yong , Ren Yiping , Luan Lianjun , Wu Yongjiang
Published: October 2011

Introduction

Chinese lantern is the calyx or calyx‐with‐fruit of the plant Physalis alkekengi .var. franchetii (Solanaceae), and is potential material for the food and pharmaceutical industries. Physalins are the most active and representative secondary metabolites of Chinese lantern. A separation and quantification method based on UPLC‐ESI‐MS/MS was developed for the quantitative analysis of five active physalins. The transformation products were also detected and identified for the first time.

Objective

To establish a LC‐MS/MS method to quantify five physalins in Chinese lantern for the purpose of quality control, and to identify the transformation products of 4,7‐didehydrophysalin B.

Methodology

The separation was carried out on an Acquity UPLC BEH Shield RP C18‐column with water and acetonitrile as the mobile phase under gradient conditions. ESI‐MS/MS was used as the detector to quantify the five physalins. The transformation products of 4,7‐didehydroneophysalin B were detected by UPLC–PDA‐ESI‐MS/MS and identified through comparing their HRMS and MS2 ion fragmentations with corresponding references.

Results

All the compounds showed good linearity (R2 > 0.998). The recoveries, measured at three concentration levels, varied from 98.8 to 101.4% with RSDs < 4.5%. The total contents of the five physalins in Chinese lantern varied significantly. Three transformation products of 4,7‐didehydroneophysalin B were detected and tentatively identified.

Conclusion

The present study developed a highly effective analytical method for the quality control of Chinese lantern, and it could provide comprehensive information for quality evaluation and new drug development of Chinese lantern. Copyright © 2011 John Wiley & Sons, Ltd.