bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodiversity of Salix spp. Honeydew and Nectar Honeys Determined by RP‐HPLC and Evaluation of Their Antioxidant Capacity
Authors: Tuberoso Carlo I. G. , Jerković Igor , Bifulco Ersilia , Marijanović Zvonimir
Published: May 2011

Rare unifloral willow (Salix spp.) honeys obtained from nectar or honeydew were investigated by direct RP‐HPLC‐DAD method in order to identify and quantify compounds that can be used as possible markers of their origin. Antioxidant and antiradical activities of willow honeys were evaluated using FRAP (=ferric reducing antioxidant assay) and DPPH (=1,1‐diphenyl‐2‐picrylhydrazyl radical) tests, respectively. Also HMF (=5‐(hydroxymethyl)furfural), diastase activity, and CIE L*a*b*C*h* chromatic coordinates were evaluated. Abscisic acids (ABA) are typical of willow nectar honey, with a predominance of (Z,E)‐ABA on (E,E)‐ABA (98.2 and 31.7 mg/kg, resp.). Kinurenic acid and salicylic acid are useful to mark willow honeydew honey. The proposed HPLC‐DAD method proved to be easy and reliable to identify the two different Salix spp. honeys, being not affected from any sample preparation artifact. Total antioxidant activity measured with the FRAP assay ranged from 3.2 to 12.6 mmol Fe2+/kg, and the antiradical activity measured with the DPPH assay ranged from 0.6 to 3.0 mmol TEAC (=Trolox equivalent antioxidant capacity)/kg in nectar and honeydew honeys, respectively. Salix spp. nectar and honeydew honeys proved to be two completely different honeys, because, besides color attributes, they show different antioxidant properties and specific compounds.
On the Putative Binding Site of RFamide‐Family Neuropeptides from the Western Atlantic Clam Sunray Venus and Cephalopods on Acid‐Sensing Ion Channels. An Automated Docking and Molecular‐Dynamics Study with hASIC1a Homology Model
Authors: Pietra Francesco
Published: May 2011

Investigated here are interactions of C‐terminal amidated peptides with the hASIC1a acid‐sensing ion channel. The peptides comprise endogenous FMRFa, present in the western Atlantic clam Sunray Venus, and FIRFa, present in cephalopods, as well as non‐endogenous ones for comparison. The interaction is investigated by automated docking. The resulting key hASIC1aFMRFa complex, set in a lipidic POPC (=1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine) membrane surrounded by H2O and Na+‐neutralized, was also investigated by molecular dynamics. It was observed that all investigated peptides become encapsulated into the ion channel, on one side by the thumb and finger of a subunit, and, on the opposite side, by the knuckle and β‐ball of a second subunit. The third subunit is not involved. This is much the same binding site that was disclosed previously by both a similar computational approach, and electrophysiological and binding experiments for the hASIC1a ion channel‐blocker tarantula toxin PCTX1. This paves the way to a better understanding of the role of these peptides in invertebrates.
Methods in Molecular Biology Vol. 671: Biological Microarrays: Methods and Protocols. Edited by Ali Khademhosseini, Kahp‐Yang Suh and Mohammed Zourob.
Authors: Schäferling Michael
Published: May 2011

Humana Press, Totowa 2010, XI+324 pp., hardcover $ 139.00.—ISBN 978‐1‐934115‐95‐4
Methane Activation over Cellulose Templated Perovskite Catalysts
Authors: Langfeld Kirsten , Marschner René , Frank Benjamin , Schomäcker Reinhard
Published: May 2011

A facile and rapid preparation method for a wide variety of medium surface area perovskite‐type catalysts on the laboratory scale is presented. The cellulose templating method allows for catalysts with high phase purity, even at the relatively low calcination temperatures. Among the versatile compositions of perovskites based on the SrCoOx system, straightforward modifications could be performed to optimize the catalytic performance in the oxidation of CH4. Substitutions in both the A and B positions in the ABO3 lattice can remarkably affect the catalytic activity. Compared to other preparation methods, the cellulose templating method is a rapid process and the catalytic performances obtained with SrCoOx and LaCoOx are at least as good as with materials prepared by conventional methods.
A Highly Porous Metal–Organic Framework: Structural Transformations of a Guest‐Free MOF Depending on Activation Method and Temperature
Authors: Park Hye Jeong , Lim Dae‐Woon , Yang Woo Seung , Oh Tae‐Rog , Suh Myunghyun Paik
Published: May 2011

A doubly interpenetrating porous metal–organic framework (SNU‐77) has been synthesized from the solvothermal reaction of the extended carboxylic acid tris(4′‐carboxybiphenyl)amine (H3TCBPA) and Zn(NO3)2⋅6H2O in N,N‐dimethylacetamide (DMA). SNU‐77 undergoes single‐crystal‐to‐single‐crystal transformations during various activation processes, such as room‐temperature evacuation, supercritical CO2 drying, and high temperature evacuation, to afford SNU‐77R, SNU‐77S, and SNU‐77H, respectively. These guest‐free MOFs exhibited different fine structures with different window shapes and different effective window sizes at room temperature. Variable‐temperature synchrotron single‐crystal X‐ray analyses reveal that the guest‐free structure is also affected by changes in temperature. Despite the different fine structures, SNU‐77R, SNU‐77S, and SNU‐77H show similar gas sorption properties due to the nonbreathing nature of the framework and an additional structural change upon cooling to cryogenic gas sorption temperature. SNU‐77H exhibits a large surface area (BET, 3670 m2 g−1), a large pore volume (1.52 cm3 g−1), and exceptionally high uptake capacities for N2, H2, O2, CO2, and CH4 gases.
Oligo(p‐phenylene‐ethynylene)s with Backbone Conformation Controlled by Competitive Intramolecular Hydrogen Bonds
Authors: Hu Wei , Yan Qifan , Zhao Dahui
Published: May 2011

A series of conjugated oligo(p‐phenylene‐ethynylene) (OPE) molecules with backbone conformations (that is, the relative orientations of the contained phenylene units) controlled by competitive intramolecular hydrogen bonds to be either co‐planar or random were synthesised and studied. In these oligomers, carboxylate and amido substituents were attached to alternate phenylene units in the OPE backbone. These functional groups were able to form intramolecular hydrogen bonds between neighbouring phenylene units. Thereby, all phenylene units in the backbone were confined in a co‐planar conformation. This planarised structure featured a more extended effective conjugation length than that of regular OPEs with phenylene units adopting random orientation due to a low rotational‐energy barrier. However, if a tri(ethylene glycol) (Tg) side chain was appended to the amido group, it enabled another type of intramolecular hydrogen bond, formed by the Tg chain folding back and the contained ether oxygen atom competing with the ester carbonyl group as the hydrogen‐bond acceptor. The outcome of this competition was proven to depend on the length of the alkylene linker joining the ether oxygen atom to the amido group. Specifically, if the Tg chain folded back to form a five‐membered cyclic structure, this hydrogen‐bonding motif was sufficiently robust to overrule the hydrogen bonds between adjacent phenylene units. Consequently, the oligomers assumed non‐planar conformations. However, if the side chain formed a six‐membered ring by hydrogen bonding with the amido NH group, such a motif was much less stable and yielded in the competition with the ester carbonyl group from the adjacent phenylene unit. Thus, the hydrogen bonds between the phenylene units remained, and the co‐planar conformation was manifested. In our system, the hydrogen bonds formed by the back‐folded Tg chain and amido NH group relied on a single oxygen atom as the hydrogen‐bond acceptor. The additional oxygen atoms in the Tg chain made a negligible contribution. A bifurcated hydrogen‐bond motif was unimportant. From our results, in combination with the results from an independent study by Meijer et al.,13 it is evident that intramolecular hydrogen bonds involving back‐folded oligo(ethylene glycol) moieties may differ in their structural details. Absorption spectroscopy served as a convenient yet sensitive technique for analysing hydrogen‐bonding motifs in our study.
Uptake of Liquid Alcohols by the Flexible FeIII Metal–Organic Framework MIL‐53 Observed by Time‐Resolved In Situ X‐ray Diffraction
Authors: Walton Richard I. , Munn Alexis S. , Guillou Nathalie , Millange Franck
Published: May 2011

A comprehensive, time‐resolved, energy‐dispersive X‐ray diffraction study of the uptake of liquid alcohols (methanol, ethanol, propan‐1‐ol and propan‐2‐ol) by the flexible metal‐organic framework solid MIL‐53(Fe)[H2O] is reported. In the case of the primary alcohols, a fluorinated version of the MIL‐53(Fe) host (C2/c symmetry V ca. 1000 Å3), in which a fraction of framework hydroxides are replaced by fluoride, shows uptake of alcohols to give initially a partially expanded phase (C2/c symmetry, V ca. 1200 Å3) followed by an expanded form of the material (either Imcm or Pnam symmetry, V ca. 1600 Å3). In the case of methanol–water mixtures, the EDXRD data show that the partially open intermediate phase undergoes volume expansion during its existence, before switching to a fully open structure if concentrated methanol is used; analogous behaviour is seen if the initial guest is propan‐2‐ol, which then is replaced by pyridine, where a continuous shift of Bragg peaks within C2/c symmetry is observed. In contrast to the partially fluorinated materials, the purely hydroxylated host materials show little tendency to stabilise partially open forms of MIL‐53(Fe) with primary alcohols and the kinetics of guest introduction are markedly slower without the framework fluorination: this is exemplified by the exchange of water by propan‐2‐ol, where a partially open C2/c phase is formed in a step‐wise manner. Our study defines the various possible pathways of liquid‐phase uptake of molecular guests by flexible solid MIL‐53(Fe).
Gram‐Scale Synthesis of Iejimalide B
Authors: Gagnepain Julien , Moulin Emilie , Fürstner Alois
Published: May 2011

Iejimalide B (2) is the most promising member of a small family of marine polyene macrolides endowed with remarkably selective activity against human cancer cell lines. As this product, however, is hardly available from the natural sources, a detailed evaluation requires the development of an efficient and practical synthetic approach. This challenge has now been met by adapting the first total synthesis of 2 previously reported by our group to the needs of high material throughput. Redesigning the access routes to the five required building blocks in combination with a careful optimization of the fragment coupling processes provided gram amounts of this valuable compound in a sequence of no more than 16 linear steps with an overall yield of about 7 %. Key elements of the successful strategy include: i) three hydrostannylation processes of elaborate terminal alkynes with “lower order” stannyl cuprates, ii) a Brown allylation, a Noyori transfer hydrogenation, and a Marshall propargylation to set the chiral centers at C9, C17, C22 and C23, and iii) a modified Takai–Utimoto olefination for the preparation of the very labile skipped 1,4‐diene flanking the ester group. The assembly process benefited from a particularly mild protocol for the Stille cross‐coupling previously developed in this laboratory, which clearly outperformed the alternative Suzuki reaction in terms of yield and scalability. The 24‐membered macrocyclic frame was forged by a remarkably selective ring‐closing metathesis reaction (RCM), in which two out of the ten double bonds present in the cyclization precursor were selectively activated with the aid of a second‐generation Grubbs catalyst.
Strain Imaging in Morbid Obesity: Insights Into Subclinical Ventricular Dysfunction
Authors: Barbosa Marcia M. , Beleigoli Alline M. , de Fatima Diniz Maria , Freire Cláudia V. , Ribeiro Antonio L. , Nunes Maria Carmo P.
Published: May 2011

Background:

Obesity has become an important health problem throughout the world. Early detection of cardiovascular abnormalities may be useful in the future for patient management. This study aimed to identify subclinical ventricular dysfunction in obese patients.

Hypothesis:

Morbid obesity is associated with ventricular dysfunction.

Methods:

Doppler echocardiogram was performed in 92 morbidly obese and in 31 healthy controls. Conventional echocardiography and tissue Doppler‐based strain imaging were used to analyze ventricular function. Intra‐ and interobserver strain imaging variabilities were tested on 15 randomly selected cases.

Results:

Left ventricular (LV) global strain (22.5% ± 3.5 vs 24.4% ± 2.5, P<0.005) and right ventricular (RV) strain (25.8% ± 5.2 vs 28.2% ± 5.2, P<0.029) were lower in obese patients when compared with healthy controls. Echocardiographic parameters of diastolic function were also different from controls. LV strain correlated with LV mass, E/e′ ratio, left atrial volume, and RV strain. At multivariate analysis, morbid obesity remained a significant determinant of global LV strain, independently of associated comorbidities.

Conclusions:

These findings suggest that incipient biventricular dysfunction is present in morbidly obese patients when new echocardiographic indices are used to investigate ventricular function. In addition, strain imaging may provide a more accurate assessment of the ventricular function in obese patients. © 2011 Wiley Periodicals, Inc.

This work was supported by grants from CNPq and FAPEMIG.

The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Cytomorphologic findings of B‐cell lymphomas with concurrent IGH/BCL2 and MYC rearrangements (dual‐translocation lymphomas)
Authors: da Cunha Santos Gilda , Ko Hyang Mi , Saieg Mauro Ajaj , Boerner Scott L. , Lai Shui Wun , Bailey Denis , Geddie William R.
Published: May 2011

BACKGROUND:

B‐cell lymphomas with concurrent IGH/BCL2 and MYC gene rearrangements, termed dual‐translocation or double‐hit lymphomas (DTLs), rarely are identified. They usually are characterized by highly aggressive behavior, a poor prognosis, and complex karyotypes. The objective of this study was to review and describe the cytomorphologic findings in different types of cytologic preparations and clinicopathologic characteristics of patients with DTLs.

METHODS:

Patient samples with IGH/BCL2 and MYC rearrangements that were detected by fluorescence in situ hybridization during the period from October 2003 to September 2009 were selected for morphology review. Clinical data and results from additional studies were collected from patient reports.

RESULTS:

Cytologic samples from 14 patients (5 men and 9 women) were reviewed. The most common cytomorphologic pattern was a mixed cell population consisting predominantly of large cells (88.2%), mainly centroblasts (94.1%), with dark blue cytoplasm (76.4%) accompanied by apoptotic bodies (64.7%), with marked cellular pleomorphism (94.1%). Nuclear segmentation was present in 64.7% of samples, conferring a “coffee bean” nucleus, and cytoplasmic vacuoles were observed in 46.6% of samples. Immunophenotyping revealed the expression of CD20, CD19, surface immunoglobulin, and CD10 in 13 samples. Other chromosomal aberrations were also identified. Seven patients died of their disease, and the time from progression to death ranged from 1 month to 16 months.

CONCLUSIONS:

Large cells with deeply basophilic cytoplasm, cytoplasmic vacuoles, and frequent segmented nuclei, particularly in fine needle aspirate smears and especially in patients with clinically aggressive and/or unusual clinical features, should trigger a fluorescence in situ hybridization analysis for IGH/BCL2 and MYC translocation to identify this entity. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.
Serum prolactin concentrations determine whether they improve or impair β‐cell function and insulin sensitivity in diabetic rats
Authors: Park Sunmin , Kim Da Sol , Daily James W. , Kim Sung‐Hoon
Published: May 2011

Background

Prolactin improves glucose homeostasis by increasing β‐cell mass under certain conditions such as pregnancy, whereas hyperprolactinaemia due to a pituitary gland adenoma tumour exacerbates insulin resistance. However, previous studies have not evaluated how prolactin modulates β‐cell function and insulin sensitivity at different dosages. Here, we determined that chronic intraperitoneal injections of different dosages of prolactin have opposite effects on insulin resistance and β‐cell function and mass in 90% pancreatectomized diabetic male rats, and the mechanisms were explored.

Methods

Diabetic rats were divided into three groups according to the dose of intraperitoneally injected prolactin for 4 weeks: (1) low dose of prolactin (25 µg/kg bw/12 h), (2) high dose of prolactin (250 µg/kg bw/12 h), and (3) vehicle. As a non‐diabetic control group, sham‐operated rats were injected with vehicle.

Results

Chronic high‐ and low‐dose prolactin injections elevated serum prolactin levels by 2.5‐ and 11.8‐fold, respectively. Both dosages promoted β‐cell mass by increasing β‐cell proliferation and neogenesis through the potentiation of phosphorylation of signal transducer and activator of transcription 5 and decreased menin expression in diabetic rats. However, only the low‐dose prolactin injection potentiated glucose‐stimulated insulin secretion though glucokinase and glucose transporter 2 induction in the diabetic rats. In addition, low‐dose prolactin decreased hepatic glucose output in hyperinsulinaemic states, indicating an improvement in hepatic insulin resistance. However, the high‐dose prolactin injection exacerbated whole‐body and hepatic insulin resistance in diabetic rats.

Conclusions

In contrast to the normal adaptive increases in glucose‐stimulated insulin secretion through expanded β‐cell mass and insulin sensitivity realized with moderately increased prolactin levels, high levels of prolactin exacerbate insulin resistance and impair the insulin‐secretory capacity in diabetic mice. Copyright © 2011 John Wiley & Sons, Ltd.
Identifying ecohydrological patterns in natural forested wetlands useful to restoration design
Authors: Johnson Yari Ben , Shear Theodore Henry , James April Lynda
Published: May 2011

Wetland restoration projects across the United States commonly lack the species and hydrology of the targeted community being restored. A better understanding of natural wetlands would help restoration project designers achieve community composition and hydrologic regimes that more closely resemble natural conditions. We investigated two different methods to identify patterns in hydrologic regime useful to restoration design. The first method was based on success criteria commonly used by North Carolina wetland mitigation projects. The second method was based on The Nature Conservancy's Indicators of Hydrologic Alteration. To test these two methods, we collected hydrologic and compositional data across the natural variation of nonriverine wet hardwood forest stands, a rare wetland community type commonly restored in North Carolina. Our results show that hydrologic parameters from the first method, based on current success criteria used in North Carolina, are not related to community composition. Hydrologic parameters from the second method, e.g. the maximum water table level over a 3‐day span, explained much of the variation in nonriverine wet hardwood forest community composition. Our results found that clear relationships do exist between hydrologic regime and community composition. Hydrologic parameters that are related to community composition need to be used as success criteria in future restoration designs. This will ensure that projects establish the appropriate hydrologic regime necessary to foster the desired wetland community type. Copyright © 2011 John Wiley & Sons, Ltd.
CD4+CD25lowGITR+ cells: A novel human CD4+ T‐cell population with regulatory activity
Authors: Bianchini Rodolfo , Bistoni Onelia , Alunno Alessia , Petrillo Maria Grazia , Ronchetti Simona , Sportoletti Paolo , Bocci Elena Bartoloni , Nocentini Giuseppe , Gerli Roberto , Riccardi Carlo
Published: May 2011

Treg subsets play a role in sustaining peripheral tolerance, are characterized by markers such as forkhead winged‐helix transcription factor (FOXP3) and CD25, and produce suppressive cytokines, such as IL‐10 and TGF‐β. Glucocorticoid‐induced TNF receptor family‐related (GITR) protein has been suggested to regulate Treg activity in mice. The aim of our study was to investigate GITR expression in human CD4+ T lymphocytes and its possible role in Treg function. Results indicate that a subset of CD4+ T cells in the peripheral blood expresses GITR and low levels of CD25 (CD4+CD25lowGITR+). These cells show Treg features as they express FOXP3, IL‐10, TGF‐β and are anergic but, as opposed to natural Tregs, express low levels of CTLA‐4 and are CD127high. CD4+CD25lowGITR+ cells represent a low percentage of the CD4+ T‐cell population (0.32–1.74%) and are mostly memory cells. Functional experiments demonstrated that CD4+CD25lowGITR+ cells have relevant suppressive activity that depends on TGF‐β. Moreover, an anti‐GITR Ab inhibited their suppressive activity, as observed in CD4+CD25+ murine Tregs. Taken together, these data indicate that human CD4+CD25lowGITR+ cells represent a distinct Treg subpopulation.
Synovial fibroblasts promote immunoglobulin class switching by a mechanism involving BAFF
Authors: Alsaleh Ghada , François Antoine , Knapp Anne‐Marie , Schickel Jean‐Nicolas , Sibilia Jean , Pasquali Jean‐Louis , Gottenberg Jacques‐Eric , Wachsmann Dominique , Soulas‐Sprauel Pauline
Published: May 2011

Fibroblast‐like synoviocytes (FLSs) are important actors in rheumatoid arthritis (RA) pathogenesis. The autoimmune nature of RA is attributed to autoantibody production, which confers to B cells a predominant role in RA. Several arguments support an induction of class switch recombination (CSR) in RA synovium, causing – in conjunction with somatic hypermutation – the production of potentially pathogenic IgG. To determine whether RA FLSs can directly promote CSR and to analyze the role of external factors like TLR signals and BAFF (B cell activating factor) family cytokines in this FLS‐B cell crosstalk, we performed cocultures of blood B cells (from normal individuals or RA patients) with RA FLSs and analyzed CSR induction by quantification of AICDA (encoding activation‐induced cytidine deaminase, AID) and switch circular transcripts expression, and IgG secretion. RA FLSs – and to a lesser extent osteoarthritis or control FLSs – promoted CSR, and TLR3 stimulation potentialized it. In addition, induction of CSR by RA FLSs was totally dependent on cell–cell contact in basal conditions, and partially dependent in the case of TLR3 stimulation. Finally, we showed that the mechanism by which RA FLSs induce CSR is mostly BAFF‐dependent. Our results support the hypothesis that CSR can be induced outside the ectopic lymphoid structures in RA.
Synthesis, Coordination Properties and Application of New N,N‐Ligands Based on Bornyl and Binaphthylazepine Chiral Backbones in Palladium‐Catalyzed Allylic Substitution Reactions
Authors: Bottari Giovanni , Meduri Angelo , Drommi Dario , Brancatelli Giovanna , Faraone Felice
Published: May 2011

The synthesis of new imine‐amine and diamine ligands, based on both the atropisomeric (Sa)‐ or (Ra)‐1,1′‐binaphthyl and (R)‐bornyl backbones, and incorporating an ethylenediamino spacer, are reported. In addition, analogue ligands in which one chiral arm is replaced by the achiral NMe2 group were synthesized. These N,N‐ligands when coordinated to a palladium metal centre form highly enantioselective catalysts for the asymmetric allylic alkylation of rac‐2‐acetoxy‐1,3‐diphenylpropene by dimethyl malonate. In one case, the synergic effect of the chirality elements in the palladium catalyst afforded the (S) substitution product with an enantiomeric excess (ee) of >99 %. Based on NMR studies of the active species in solution, a reliable explanation for the origin of the enantioselectivity of these palladium catalysts is also provided.
Polymers for Green C–C Couplings (Eur. J. Inorg. Chem. 15/2011)
Authors: Albéniz Ana C. , Carrera Nora
Published: May 2011

The cover picture shows how palladium‐catalyzed cross coupling reactions can be carried out in a clean and green way by attaching either the reagents (bottom) or the catalyst (upper right) to polymers, here represented as branches of a blooming tree. This is the topic of the Microreview by A. C. Albéniz and N. Carrera on p. 2347 ff, where examples of polymer‐supported palladium catalysts or polymer‐attached reagents (specially organotin derivatives in the Stille reaction) are discussed. The water in the background of the picture suggests that this solvent can also be used in couplings where the catalyst is supported on a polymeric scaffold.
Insight into the Mechanism of Quinoline Formation by the Chromium(0) Fischer Carbene Catalytic Transmetallation to Palladium and Rhodium: Application to the Synthesis of the Alkaloids of Ruta chalepensis
Authors: López‐Alberca María P. , Fernández Israel , Mancheño María J. , Gómez‐Gallego Mar , Casarrubios Luis , Sierra Miguel A.
Published: May 2011

The Pd‐ and Rh‐mediated cyclization of group 6 (2‐aminoethenyl)carbene complexes incorporating aryl iodides or boronates in their structures is reported. The process led to the formation of quinoline rings and has been applied to the synthesis of quinoline alkaloids 12 and 13 isolated from the roots of the perennial grass Ruta chalepensis. The computational (DFT) study of the cyclization processes revealed unusual features. Thus, for the Pd‐mediated cyclization of (2‐aminoethenyl)carbene complexes incorporating aryl iodides in their structures, the first step in the pathway to the quinolines is the Cr‐to‐Pd transmetallation reaction, leading to palladacarbenes instead of the expected oxidative addition to the aryl iodide. For RhI‐mediated cyclizations in (2‐aminoethenyl)carbene complexes incorporating aryl boronates, the sequence of events involves an initial Cr‐to‐Rh transmetallation followed by oxidative addition to the aryl–boron bond. The evolution of these intermediates to the final quinolines parallels the Pd‐catalyzed pathway.
Synthesis of Naturally Occurring Cyclohexene Rings Using Stereodirected Intramolecular Diels–Alder Reactions Through Asymmetric 1,3‐Dioxane Tethering (Eur. J. Org. Chem. 15/2011)
Authors: Abdelkafi Hajer , Evanno Laurent , Deville Alexandre , Dubost Lionel , Chiaroni Angèle , Nay Bastien
Published: May 2011

The cover picture shows a synthetic n‐puzzle, a game that challenges players to move tiles along unbending routes in order to establish a certain end configuration. Our templated 1,3,9‐decatrienoate precursors, advanced synthetic tiles, were designed on the basis of a chiral 1,3‐dioxane tether and paved the way for stereodirected intramolecular Diels–Alder reactions, leading to asymmetric cyclohexene rings. The 1,3‐dioxane tether was expected to rigidify the decatrienoate system for efficient stereocontrol, with the ester carbonyl group strongly favoring endo‐boat transitions states. Thanks to this method we succeeded in synthesizing valuable intermediates towards the total synthesis of the diterpene harringtonolide originating from the plum yew shown in the background and the fungal polyketide pyrrocidine A. Details of this work are described in the article by B. Nay et al. on p. 2789 ff.
Appealing to common humanity increases forgiveness but reduces collective action among victims of historical atrocities
Authors: Greenaway Katharine H. , Quinn Emerald A. , Louis Winnifred R.
Published: May 2011

Appealing to common humanity is often suggested as a method of uniting victims and perpetrators of historical atrocities. In the present experiment (N = 109), we reveal that this strategy may actually work against victim groups' best interests. Appealing to common humanity (versus intergroup identity) increased forgiveness of perpetrators but independently also served to lower intentions to engage in collective action. Both effects were mediated but not moderated by reduced identification with the victim group. We, thus reveal an important feature of appeals to common humanity: That this strategy may reduce social change at the same time as helping to promote more positive intergroup attitudes. These novel findings extend research on the human identity to a new theoretically interesting and socially important domain. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and Application of Urea Electrochemical Sensor Based on Chitosan Molecularly Imprinted Films
Authors: Chen Yan‐Ping , Liu Bin , Lian Hui‐Ting , Sun Xiang‐Ying
Published: May 2011

A novel urea electrochemical sensor was constructed based on chitosan molecularly imprinted films which were prepared by potentiostatic electrodeposition of chitosan in the presence of urea followed by eluting with 0.1 M KCl. Various techniques were carried out to investigate the formation of molecularly imprinted polymer (MIP) films and the performance of the sensor. According to our expectation, the urea MIP electrochemical sensor showed excellent selectivity to urea among the structural similarities and co‐existences, high linear sensitivity to urea in the range from 1.0×10−8 to 4.0×10−5 M with a detection limit of 5.0×10−9 M. Furthermore, the recovery ranged from 96.3 % to 103.3 % and therefore offered great potential for clinical diagnosis applications.
A DNA-based assay for toxic chemicals in wastewater
Authors: Foreman Amy L , Phillips Leo , Kanellis Vangelis G , Hammoudeh Daoud , Naumann Christoph , Wong Henri , Chisari Robert , Hibbert D. Brynn , Lee Garry S.H , Patra Ronald , Julli Moreno , Chapman John , Cooke A. Roger , dos Remedios Cristobal G
Published: May 2011

Chemical toxicants, particularly metal ions, are a major contaminant in global waterways. Live-organism bioassays used to monitor chemical toxicants commonly involve measurements of activity or survival of a freshwater cladoceran (Ceriodaphnia dubia) or light emitted by the marine bacterium Vibrio fischeri, used in the commercial Microtox® bioassay. Here we describe a novel molecule-based assay system employing DNA as the chemical biosensor. Metals bind to DNA, causing structural changes that expel a bound (intercalated) fluorescent reporter dye. Analyses of test data using 48 wastewater samples potentially contaminated by metal ions show that the DNA-dye assay results correlate with those from C. dubia and Microtox bioassays. All three assays exhibit additive, antagonistic, and synergistic responses that cannot be predicted by knowing individual metal concentrations. Analyses of metals in these samples imply the presence of chemical toxicants other than metal ions. The DNA-dye assay is robust, has a 12-month shelf life, and is only slightly affected by sample pH in the range 4 to 9. The assay is completed in a matter of minutes, and its portability makes it well suited as a screening assay for use in the field. We conclude that the DNA-dye test is a surrogate bioassay suitable for screening chemical toxicity. Environ. Toxicol. Chem. 2011; 30:1810–1818. © 2011 SETAC
Surface Fluorination of Poly(fluorenyl ether ketone) Ionomers as Proton Exchange Membranes for Fuel Cell Application
Authors: Hu H. , Xiao M. , Wang S. J. , Shen P. K. , Meng Y. Z.
Published: May 2011

A series of sulphonated poly(fluorenyl ether ketone) ionomers were successfully fluorinated by the means of direct surface fluorination. Polymer ionomer samples in two different states (membrane and powder) were treated with F2 gas which is diluted in N2 in a special reactor. X‐ray photoelectron spectroscopy (XPS) was used to examine the F/C ratios of the fluorinated materials. The results revealed that the fluorination only occurred on the membrane surface and the fluorination degree increased with increasing F2 concentration in N2. The membrane subjected to fluorination shows an obviously enhanced oxidative stability. The endurance in a Fenton's reagent of FSPFEK‐P‐28 is longer than 180 min which is two times longer than that of un‐fluorinated SPFEK. The PEM properties and single fuel cell performances were investigated by comparison of un‐ and fluorinated polymer ionomers. The fluorinated membranes demonstrated an enhanced hydrophobic surface property, increased proton conductivities and better single fuel cell performances. Surface fluorination provides a convenient and useful approach to prepare highly proton conductive membrane with long life‐time PEM fuel cell applications.
The Role of Reactive Reaction Intermediates in Two‐Step Heterogeneous Electrocatalytic Reactions: A Model Study
Authors: Fuhrmann J. , Zhao H. , Langmach H. , Seidel Y. E. , Jusys Z. , Behm R. J.
Published: May 2011

This paper summarises the result of previous experimental investigations of heterogeneous electrocatalytic reactions performed in flow cells which provide an environment with controlled parameters. Measurements of the oxygen reduction reaction in a flow cell with an electrode consisting of an array of Pt nanodisks on a glassy carbon substrate exhibited a decreasing fraction of the intermediate H2O2 in the overall reaction products with increasing density of the nanodisks. A similar result is true for the dependence on the catalyst loading in the case of a supported Pt/C catalyst thin‐film electrode, where the fraction of the intermediate decreases with increasing catalyst loading. Similar effects have been detected for the methanol oxidation.

In order to give a possible explanation to the observed effect, we present a model of multistep heterogeneous electrocatalytic oxidation and reduction reactions based on an adsorption‐reaction‐desorption scheme using the Langmuir assumption and macroscopic transport equations. A continuum based model problem in a vertical cross‐section of a rectangular flow cell is proposed in order to explain basic principles of the experimental situation. It includes three model species A, B, C, which undergo adsorption and desorption at a catalyst surface, as well as adsorbate reactions from A to B to C. These surface reactions are coupled with diffusion and advection in the Hagen Poiseuille flow in the flow chamber of the cell. High velocity asymptotic theory and a finite volume numerical method are used to obtain approximate solutions to the model. Both approaches show a behaviour similar to the experimentally observed. Working in more general situations, the finite volume scheme was applied to a catalyst layer consisting of a number of small catalytically active areas corresponding to nanodisks. Good qualitative agreement with the experimental findings is established for this case as well.
Effects of rollover strategies and information stability on the performance measures in options markets: An examination of the KOSPI 200 index options market
Authors: Choi Youngsoo , Ok SoonChan
Published: May 2011

One of the most widely used option valuation models among practitioners is the ad hoc Black–Scholes (AHBS) model. The main contribution of this study is methodological. We carefully consider two rollover strategies (nearest‐to‐next strategy and next‐to‐next) used in the AHBS model to investigate their effect on pricing errors. We suggest a new rollover strategy, next‐to‐next strategy, and demonstrate that our rollover strategy produces more consistent estimates between in‐sample market and model option prices. Probably even more important is that our new rollover strategy makes more accurate out‐of‐sample forecasts for 1‐day or 1‐week ahead prices. Prior literature has documented some anomalies associated with the use of AHBS model, for example, an overfitting problem. A secondary contribution is that our new rollover strategy does not suffer from this overfitting critique. Third, this study uses the mean square error for out‐of‐sample pricing and price changes to determine how the options investors are influenced by moneyness. The results indicate that underpricing (or overpricing) by the AHBS model for the near‐the‐money category is more likely to be maintained for the next several trading days but that such a phenomenon is disappeared for the deep out‐of‐the‐money category. Finally, we suggest the ratio of the number of option contracts to differences in strike prices available for trading between the current day and the previous day(s) as a good categorizing factor for options, such as moneyness. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark
Efficient synthesis of α‐aminophosphonates via one‐pot reactions of aldehydes, amines, and phosphates in ionic liquid
Authors: Hajinasiri Rahimeh , Hossaini Zinatossadat , Rostami‐Charati Faramarz
Published: May 2011

Ionic liquids such as 1,3‐dialkylimidazolium bromides make excellent solvents for synthesis of α‐aminophosphonates from aldehydes, amines, and phosphites. The ionic liquids are successfully regenerated and reused. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:625–629, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20724
Quantile regression analysis of body mass and wages
Authors: Johar Meliyanni , Katayama Hajime
Published: May 2011

Using the National Longitudinal Survey of Youth 1979, we explore the relationship between body mass and wages. We use quantile regression to provide a broad description of the relationship across the wage distribution. We also allow the relationship to vary by the degree of social skills involved in different jobs. Our results find that for female workers body mass and wages are negatively correlated at all points in their wage distribution. The strength of the relationship is larger at higher‐wage levels. For male workers, the relationship is relatively constant across wage distribution but heterogeneous across ethnic groups. When controlling for the endogeneity of body mass, we find that additional body mass has a negative causal impact on the wages of white females earning more than the median wages and of white males around the median wages. Among these workers, the wage penalties are larger for those employed in jobs that require extensive social skills. These findings may suggest that labor markets reward white workers for good physical shape differently, depending on the level of wages and the type of job a worker has. Copyright © 2011 John Wiley & Sons, Ltd.
ent‐Kaurane Diterpenes and Further Constituents from Wedelia trilobata
Authors: Qiang Yin , Du Dao‐Lin , Chen Yan‐Jun , Gao Kun
Published: May 2011

Two new ent‐kaurane diterpenes, wedelidins A (8) and B (9), together with eighteen other constituents, including the sesquiterpenoids 1 and 2, ent‐kaurane diterpenes 3–7, triterpenoids 10 and 11, steroids 12–14, and flavonoids 15–17 as well as benzene derivatives 18–20, were isolated from the aerial parts of Wedelia trilobata. The structures of wedelidins A (8) and B (9) were elucidated by extensive spectroscopic analyses (including UV, IR, NMR, and MS). Furthermore, the structures of compounds 2 and 3 were confirmed by X‐ray single‐crystal diffraction analyses.
Organic Reaction in Water: A Highly Efficient and Environmentally Friendly Synthesis of Spiro Compounds Catalyzed by L‐Proline
Authors: Dabiri Minoo , Noroozi Tisseh Zeinab , Nobahar Mohsen , Bazgir Ayoob
Published: May 2011

We have developed a clean, simple and efficient method for the synthesis of spiro compounds by three‐component reaction of isatins (=1H‐indole‐2,3‐diones) or acenaphthylene‐1,2‐dione, 1,3‐diphenyl‐1H‐pyrazoles‐5‐amines, and tetronic acid (=furan‐2,4‐(3H,5H)‐dione or 2‐hydroxy‐1,4‐naphthoquinone in the presence of a catalytic amount of L‐proline in aqueous media. The advantages of this procedure are mild reaction conditions, high yields of products, operational simplicity, and easy workup procedures employed.
A New Tetracyclic Diterpene from Jatropha curcas
Authors: Xu Jun‐Ju , Fan Jun‐Ting , Zeng Guang‐Zhi , Tan Ning‐Hua
Published: May 2011

Jatrophodione A (1), a new diterpene with four rings, together with nine known compounds, caniojane (2), jatropholone A (3), jatropholone B (4), jatrogrossidione (5), 2‐epijatrogrossidione (6), heudelotinone (7), gossweilone (8), (3α)‐3‐hydroxy‐ent‐pimara‐8(14),15‐dien‐12‐one (9), and 12‐hydroxy‐13‐methylpodocarpa‐8,11,13‐trien‐3‐one (10), was isolated from the aerial parts of Jatropha curcas. Compounds 5, 6, 9, and 10 were found for the first time in this plant. Their structures were established by spectroscopic analysis, including 2D‐NMR spectroscopic techniques. Cytotoxicities of compounds 1, 2, 7, 8, and 9 were tested on the three cancer cell lines A549, Hela, and SMMC‐7721. Results showed that 7 exhibited cytotoxicity against SMMC‐7721 with an IC50 value of 21.68 μM, whereas 7 and 8 were active against A549 with the IC50 values of 16.04 and 20.47 μM, and against Hela with the IC50 values of 10.67 and 22.83 μM, respectively.
Novel Cyanoglucosides from the Leaves of Hydrangea macrophylla
Authors: Wang Zhi‐Bin , Gao Hui‐Yuan , Yang Chun‐Juan , Sun Zhi , Wu Li‐Jun
Published: May 2011

Four non‐cyanogenic cyanoglucosides including hydranitrilosides A1, A2, B1, and B2 (1–4, resp.), together with a new phenolic glucoside, 3‐hydroxy‐4‐methoxybenzoic acid 3‐O‐β‐D‐glucopyranoside (5), were isolated from the leaves of Hydrangea macrophylla. Their structures were determined on the basis of chemical and spectral evidence.
Convergent Domino Knoevenagel Hetero‐DielsAlder and Domino Oxidation Hetero‐DielsAlder Reactions Encountered in an Unexpected Formation of Novel 5‐Aryl‐1H‐pyrano[2,3‐d]pyrimidine‐2,4(3H,5H)‐diones and 5‐Aryl‐2,3‐dihydro‐2‐thioxo‐1H‐pyrano[2,3‐d]pyrimidin‐4(5H)‐ones
Authors: Zidar Nace , Kikelj Danijel
Published: May 2011

Convergent domino Knoevenagel hetero‐DielsAlder and domino oxidation hetero‐DielsAlder reactions, in which both diene and dienophile are formed under the same reaction conditions in situ, are described for the first time, and their application is demonstrated by a one‐pot synthesis of novel 5‐aryl‐1H‐pyrano[2,3‐d]pyrimidine‐2,4(3H,5H)‐diones and 5‐aryl‐2,3‐dihydro‐2‐thioxo‐1H‐pyrano[2,3‐d]pyrimidin‐4(5H)‐ones.
Synthesis of Allyl Aryl Sulfone Derivatives from BaylisHillman Acetates in Water
Authors: Karnakar Konkala , Shankar Jilla , Narayana Murthy Sabbavarapu , Nageswar Yadavalli Venkata Durga
Published: May 2011

Various phenyl and p‐tolyl allyl sulfone derivatives were prepared stereoselectively by reacting BaylisHillman acetates with sodium 4‐R‐benzenesulfinate (R=H, Me) in H2O. The reaction was very efficient in providing the corresponding sulfone derivatives in good to excellent yields (Table).
An Efficient Stereoselective Total Synthesis of Synargentolide A and Its Epimer
Authors: Das Biswanath , Balasubramanyam Penagaluri , Veeranjaneyulu Boyapati , Chinna Reddy Gandolla
Published: May 2011

The stereoselective total synthesis of a naturally occurring α‐pyrone (=2H‐pyran‐2‐one) derivative, synargentolide A (1), and of its epimer 2 (with the originally proposed structure of synargentolide A) was efficiently accomplished involving D‐tartaric acid as the starting material and an olefin cross‐metathesis reaction as the key step.
New Polyketides Isolated from Botryosphaeria australis Strain ZJ12‐1A
Authors: Xu Yu‐Hang , Lu Chun‐Hua , Zheng Zhong‐Hui , Shen Yue‐Mao
Published: May 2011

Four new polyketides, botryosphaerones A–D (1–4, resp.), were obtained from the fermentation culture of Botryosphaeria australis strain ZJ12‐1A, together with four known compounds, O‐methylasparvenone (5), 6‐ethyl‐2,7‐dimethoxyjuglon (6) and its monoacetyl derivative 7, and O‐methylaspmenone (8). Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and HR‐Q‐TOF mass spectrometry, and by comparison with reported data. All compounds were evaluated for their cytotoxic and antimicrobial activities in vitro. Only compounds 6 and 7 showed cytotoxic and antimicrobial activities, as already reported.
Synthesis of trans‐Fused Oxabicyclo[5.2.0]nonan‐2‐ones via [2+2] Photocycloaddition of Oxepinones to Conjugated Alkenes
Authors: Schmidt Kerstin , Margaretha Paul
Published: May 2011

On irradiation (350 nm) in the presence of 2,3‐dimethylbuta‐1,3‐diene, benzoxepinone 2 and dioxepinone 3 were converted regio‐ and diastereoselectively to trans‐fused oxabicyclo[5.2.0]nonanones 5 and 9, respectively.
Reaction of Optically Active Oxiranes with Thiofenchone and 1‐Methylpyrrolidine‐2‐thione: Formation of 1,3‐Oxathiolanes and Thiiranes
Authors: Fu Changchun , Linden Anthony , Heimgartner Heinz
Published: May 2011

The SnCl4‐catalyzed reaction of (−)‐thiofenchone (=1,3,3‐trimethylbicyclo[2.2.1]heptane‐2‐thione; 10) with (R)‐2‐phenyloxirane ((R)‐11) in anhydrous CH2Cl2 at −60° led to two spirocyclic, stereoisomeric 4‐phenyl‐1,3‐oxathiolanes 12 and 13 via a regioselective ring enlargement, in accordance with previously reported reactions of oxiranes with thioketones (Scheme 3). The structure and configuration of the major isomer 12 were determined by X‐ray crystallography. On the other hand, the reaction of 1‐methylpyrrolidine‐2‐thione (14a) with (R)‐11 yielded stereoselectively (S)‐2‐phenylthiirane ((S)‐15) in 56% yield and 87–93% ee, together with 1‐methylpyrrolidin‐2‐one (14b). This transformation occurs via an SN2‐type attack of the S‐atom at C(2) of the aryl‐substituted oxirane and, therefore, with inversion of the configuration (Scheme 4). The analogous reaction of 14a with (R)‐2‐{[(triphenylmethyl)oxy]methyl}oxirane ((R)‐16b) led to the corresponding (R)‐configured thiirane (R)‐17b (Scheme 5); its structure and configuration were also determined by X‐ray crystallography. A mechanism via initial ring opening by attack at C(3) of the alkyl‐substituted oxirane, with retention of the configuration, and subsequent decomposition of the formed 1,3‐oxathiolane with inversion of the configuration is proposed (Scheme 5).
The ‘t‐Amino Effect’ of ortho‐Nitroso Amines. Synthesis of 2,6‐Diaminoadenine Derivatives from 6‐(Dialkylamino)‐5‐nitrosopyrimidines
Authors: del Carmen Ruiz Ruiz Maria , Vasella Andrea
Published: May 2011

The ‘t‐amino effect’ of amino‐nitroso compounds was documented by preparing the (dialkylamino)‐nitroso pyrimidines 4–18, and cyclising them under thermal conditions in high yields to the purine derivatives 19–32. The reactivity of the amino‐nitroso‐pyrimidines, particularly of 17 derived from diethyl iminodiacetate, and of 19, derived from 1‐phenylimidazolidine, correlates with the stability of the intermediate azomethine ylide. Thermolysis of the amino‐nitroso‐pyrimidines 34–37, possessing dialkylamino substituents at C(4) and C(6), proceeded by protiodenitrosation, leading to 38–41.