bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Complex of Cytochrome f and Plastocyanin from Nostoc sp. PCC 7119 is Highly Dynamic
Authors: Scanu Sandra , Förster Johannes , Finiguerra Michela G. , Shabestari Maryam Hashemi , Huber Martina , Ubbink Marcellus 
Published: May 2012

AbstractCytochrome f (Cyt f) and plastocyanin (Pc) form a highly transient complex as part of the photosynthetic redox chain. The complex from Nostoc sp. PCC 7119 was studied by NMR relaxation spectroscopy with the aim of determining the orientation of Pc relative to Cyt f. Chemical‐shift‐perturbation analysis showed that the presence of spin labels on the surface of Cyt f does not significantly affect the binding of Pc. The paramagnetic relaxation enhancement results are not consistent with a single orientation of Pc, thus indicating that multiple orientations must occur and suggesting that an encounter state represents a large fraction of the complex.
Catalytic NO Oxidation Pathways and Redox Cycles on Dispersed Oxides of Rhodium and Cobalt
Authors: Weiss Brian M. , Artioli Nancy , Iglesia Enrique 
Published: May 2012

AbstractThe elementary steps and site requirements for the oxidation of NO on Rh and Co and the oxidation state of the catalysts were probed by isotopic tracers, chemisorption methods, and kinetic measurements of the effects of the pressures of NO, O2, and NO2 on turnover rates. On both catalysts, NO oxidation rates were first order in NO and O2 and were inversely proportional to NO2 pressure, as observed on Pt and PdO. These data implied that O2 activation on an isolated vacancy (*) on the catalyst surfaces that were saturated with oxygen (O*) was the kinetically relevant step. Quasi‐equilibrated NO–NO2 interconversion steps established the coverage of * and O* and the chemical potential of oxygen during the catalysis. These chemical potentials set the oxidation state of Rh and Co clusters and were described by an O2 virtual pressure, which was determined from the formalism of non‐equilibrium thermodynamics. RhO2 and Co3O4 were the phases that were present during NO oxidation, which had several consequences for catalysis. Turnover rates increased with increasing cluster size because the vacancies that were needed for O2 activation were more abundant on large oxide clusters, which delocalized electrons better than small clusters. NO oxidation turnover rates on RhO2 and Co3O4 were higher than expected from the oxygen‐binding energy on Rh and Co metal surfaces and from the reduction potentials of Rh3+ and Co2+. These NO oxidation rates were consistent with the rates on Pt and PdO when one‐electron‐reduction processes, which were accessible for Rh4+ and Co3+ but not for Pt2+ and Pd2+, were used to describe the reactivity of RhO2 and Co3O4. One‐electron redox cycles caused the 16O2–18O2 exchange rates to be higher than the NO oxidation rates, in contrast with their analogous values on Pt and PdO, although O2 activation on the vacancies limited NO oxidation and O2 exchange on all of the catalysts. One‐electron redox cycles allowed electron sharing between metal cations and a facile route to form vacancies on RhO2 and Co3O4. This interpretation of the data highlighted the role of vacancies in kinetically relevant O2‐activation steps to explain the higher reactivity of larger metal and oxide clusters and to provide a common framework to describe NO oxidation and the active species on catalysts of practical interest.
Isomerization and Dimerization of Pinene using Al‐Incorporated MCM‐41 Mesoporous Materials
Authors: Zou Ji‐Jun , Chang Na , Zhang Xiangwen , Wang Li 
Published: May 2012

AbstractA series of Al‐incorporated mobile crystalline materials (Al‐MCM‐41) were prepared by hydrothermal synthesis and characterized by XRD, N2 adsorption (isotherms), inductively coupled plasma (ICP) analysis, 27Al magic angle spinning (MAS) NMR spectroscopy, and in situ pyridine adsorption (IR analysis). All samples exhibit an ordered structure with the majority of Al species in framework positions, except those with an SiO2/Al2O3 ratio ≤10. The concentration of acid sites is closely related to the Al content in the unit cell. In the presence of Al‐MCM‐41, both α‐ and β‐pinenes are quickly transformed into isomerized products, which then couple to form homo‐ and heterodimers. Lewis acid sites are active in triggering both the isomerization and dimerization reactions, but weak Brønsted acid sites seem inactive for the dimerization. Al‐MCM‐41 has a greater activity than many other microporous and layered materials, and can be easily regenerated. The activity correlates well with the concentration of acid sites, and the sample with an SiO2/Al2O3 ratio of 20 shows the highest activity.
Aromatic‐Amide‐Derived Olefins as a Springboard: Isomerization‐Initiated Palladium‐Catalyzed Hydrogenation of Olefins and Reductive Decarbonylation of Acyl Chlorides with Hydrosilane
Authors: Bai Xing‐Feng , Xu Li‐Wen , Zheng Long‐Sheng , Jiang Jian‐Xiong , Lai Guo‐Qiao , Shang Jun‐Yan 
Published: May 2012

AbstractA highly efficient catalytic protocol for the isomerization of substituted amide‐derived olefins is presented that successfully uses a hydride palladium catalyst system generated from [PdCl2(PPh3)2] and HSi(OEt)3. The Z to E isomerization was carried out smoothly and resulted in geometrically pure substituted olefins. Apart from the cis–trans isomerization of double bonds, the selective reduction of terminal olefins and activated alkenes was performed with excellent functional group tolerance in the presence of an amide‐derived olefin ligand, and the products were obtained in high isolated yields (up to >99 %). Furthermore, the palladium/hydrosilane system was able to promote the reductive decarbonylation of benzoyl chloride when a (Z)‐olefin with an aromatic amide moiety was used as a ligand.
Liquid Chromatographic Separation of Darunavir Enantiomers on Coated and Immobilized Amylose Tris(3, 5‐Dimethylphenylcarbamate) Chiral Stationary Phases
Authors: Rao Ramisetti Nageswara , Kumar Kandukuri Nagesh , Naidu Challa Gangu 
Published: May 2012

ABSTRACTLiquid chromatographic separation of darunavir enantiomers on covalently bonded and physically adsorbed polysaccharide chiral stationary phases was studied at different temperatures. The separations were accomplished under normal‐phase conditions by using different combinations of hexane, organic modifiers (2‐propanol, 1‐propanol and ethanol), and diethylamine as mobile phase solvents. The effect of organic modifiers and the column temperature on retention, separation, and resolution was investigated. The observed differences were explained in terms of the coated and immobilized nature of the two columns. Van't Hoff plots (ln k′ vs. 1/T, ln α vs. 1/T) and apparent thermodynamic parameters were derived to understand the effect of temperature on separation. Chirality 24:652–660, 2012. © 2012 Wiley Periodicals, Inc.
Studies on the Solvation Dynamics of Coumarin 153 in 1‐Ethyl‐3‐Methylimidazolium Alkylsulfate Ionic Liquids: Dependence on Alkyl Chain Length
Authors: Kumar Das Sudhir , Sarkar Moloy 
Published: May 2012

AbstractSteady‐state and time‐resolved fluorescence behavior of coumarin 153 (C153) is investigated in a series of 1‐ethyl‐3‐methylimidazolium alkylsulfate ([C2mim][CnOSO3]) ionic liquids differing only in the length of the linear alkyl chain (n=4, 6, and 8) in the anion. The aim of the present study is to understand the role of alkyl chain length in solute rotation and solvation dynamics of C153 in these ionic liquids. The blueshift observed in the steady‐state absorption and emission maxima of C153 on going from the C4OSO3 to the C8OSO3 system indicates increasing nonpolar character of the microenvironment of the solute with increasing length of the alkyl side chain of the anion of the ionic liquids. The average solvation time is also found to increase on changing the substituent from butyl to octyl, and this is attributed to the increase in the bulk viscosity of the ILs. A steady blueshift of the time‐zero maximum of the fluorescence spectrum with increasing alkyl chain length also indicates that the probe molecule experiences a less polar environment in the early part of the dynamics. Rotational dynamics of C153 are also analyzed by using the Stokes–Einstein–Debye (SED), Gierer–Wirtz (GW), and Dote–Kivelson–Schwartz (DKS) theories. Analyses of the results seem to suggest decoupling of the rotational motion of the probe from solvent viscosity.
Molecular genetic characterization of lymphoma: Application to cytology diagnosis
Authors: Ochs Rachel C. , Bagg Adam 
Published: May 2012

AbstractMature B‐ and T‐cell lymphomas are increasingly being associated with specific genetic alterations; characterization of these changes can sometimes be crucial to both diagnosis and prognosis. Molecular testing encompasses florescence in situ hybridization (FISH) and polymerase chain reaction (PCR)‐based assays, as well as classical cytogenetics. FISH and PCR‐based assays can be performed on cytology material without the need for advanced planning for testing with fresh tissue. As many lymphoproliferations are amenable to fine needle aspiration diagnosis, it is important for the cytopathologist to be aware of what testing is feasible in these (sometimes limited) specimens. Here, we review pertinent genetic changes in mature B‐ and T‐cell lymphomas with a focus on those that may be encountered more commonly in cytology specimens. Diagn. Cytopathol. 2012;40:542–555. © 2012 Wiley Periodicals, Inc.
The role of cytology specimens in molecular testing of solid tumors: Techniques, limitations, and opportunities
Authors: Aisner Dara L. , Sams Sharon B. 
Published: May 2012

AbstractNumerous studies have demonstrated the suitability of cytology specimens for molecular analysis. When combined with the ability to acquire tissue in a minimally invasive manner, testing on cytology specimens is an especially attractive method for further refining diagnosis, determining prognosis, and predicting likely response to therapy as well as monitoring disease. As the demand for testing of small specimens increases, the burden of determining whether a specimen should be referred for testing will increasingly be placed on the pathologist. Although molecular laboratories that perform this testing will also evaluate the suitability of the specimen, familiarity with the criteria for suitability, which includes an understanding of the limitations of the assay methodology, will assist in determining which specimens are appropriate for referral. Selection of specimen(s) for testing should be paired with knowledge of the testing methodology used and its limitations, as well as the tumor enrichment capabilities of the laboratory. In addition to an expanding need to participate in the referral of specimens for testing, the cytopathologist will increasingly serve as a critical link in the communication between molecular laboratory and clinical team. Diagn. Cytopathol. 2012;40:511–524. © 2012 Wiley Periodicals, Inc.
Effects of adaptation, chance, and history on the evolution of the toxic dinoflagellate Alexandrium minutum under selection of increased temperature and acidification
Authors: Flores‐Moya Antonio , Rouco Mónica , García‐Sánchez María Jesús , García‐Balboa Camino , González Raquel , Costas Eduardo , López‐Rodas Victoria 
Published: May 2012

AbstractThe roles of adaptation, chance, and history on evolution of the toxic dinoflagellate Alexandrium minutum Halim, under selective conditions simulating global change, have been addressed. Two toxic strains (AL1V and AL2V), previously acclimated for two years at pH 8.0 and 20°C, were transferred to selective conditions: pH 7.5 to simulate acidification and 25°C. Cultures under selective conditions were propagated until growth rate and toxin cell quota achieved an invariant mean value at 720 days (ca. 250 and ca. 180 generations for strains AL1V and AL2V, respectively). Historical contingencies strongly constrained the evolution of growth rate and toxin cell quota, but the forces involved in the evolution were not the same for both traits. Growth rate was 1.5–1.6 times higher than the one measured in ancestral conditions. Genetic adaptation explained two‐thirds of total adaptation while one‐third was a consequence of physiological adaptation. On the other hand, the evolution of toxin cell quota showed a pattern attributable to neutral mutations because the final variances were significantly higher than those measured at the start of the experiment. It has been hypothesized that harmful algal blooms will increase under the future scenario of global change. Although this study might be considered an oversimplification of the reality, it can be hypothesized that toxic blooms will increase but no predictions can be advanced about toxicity.
Assembly of Saturated Nb/W Mixed‐Addendum Polyoxometalate [P2W15Nb3O62]9– and Lanthanide Ions (Ln = Eu, Ce)
Authors: Li Cong‐Cong , Liu Shu‐Xia , Li Shu‐Jun , Yang Yuan , Jin Hai‐Yan , Ma Feng‐Ji 
Published: May 2012

AbstractTwo isostructural polyoxotungstates, K6Na4H8[Eu6(H2O)38(P2W15Nb3O62)4]·45H2O (1) and K6Na4H8[Ce6(H2O)38(P2W15Nb3O62)4]·56H2O (2), have been synthesized by reactionof saturated Nb/W mixed‐addendum polyoxometalate [P2W15Nb3O62]9– and lanthanide ions in acidic solution. They are the first examples of lanthanide derivatives based on saturated Dawson‐type Nb/W mixed‐addendum polyoxometalates. All the compounds were fully characterized by single‐crystal X‐ray diffraction, IR spectroscopy, thermogravimetric analysis, elemental analysis, and electrochemistry. XRD analysis reveals that 1 and 2 display one‐dimensional chains constructed from sandwich‐type fragment {Ln3(P2W15Nb3O62)2} linked by alternating Ln–O–W bridging bonds. In 1 and 2, all the lanthanide ions selectively bind to Ot(Nb) of {P2W15Nb3O62} fragments (Ot: terminal oxygen atoms), indicating the high nucleophilicity of Ot(Nb). The photoluminescence behavior of 1 in the solid state was investigated at room temperature; it exhibits the characteristic transition of Eu under the excitation wavelength (394 nm). Additionally, the cyclic voltammogram of 2 indicates good electrocatalytic activity towards the reduction of nitrite.
Heck–Matsuda Arylation as a Strategy to Access Kavalactones Isolated from Polygala sabulosa, Piper methysticum, and Analogues
Authors: Soldi Cristian , Moro Angélica V. , Pizzolatti Moacir G. , Correia Carlos R. D. 
Published: May 2012

AbstractHerein, we describe the total syntheses of three bioactive pyrones isolated from Polygala sabulosa (i.e., 1, 4, and 7) and eight isolated from Piper methysticum (i.e., 8–10, 13, 15, and 18–20) using the Heck–Matsuda arylation as the key strategy. The evaluation of this methodology by employing different arenediazonium tetrafluoroborates revealed that the Heck arylation was more efficient when the olefin undergoing arylation possessed the vinyl‐2‐pyrone structural unit instead of the vinyl dihydro‐2‐pyrone moiety. The Heck–Matsuda arylation of many of the examined olefins proceeded in a practical manner with total regio‐ and stereocontrol.
Landslide Amplification by Liquefaction of Runout‐Path Material after the 2008 Wenchuan (M 8·0) Earthquake, China
Authors: Wang Gonghui , Huang Runqiu , Chigira Masahiro , Wu Xiyong , Lourenço Sérgio D. N. 
Published: May 2012

ABSTRACTHere, we propose that an earthquake can trigger the failure of a landslide mass while simultaneously triggering liquefaction of runout‐path materials before the arrival of the landslide mass, thus greatly increasing the size and mobility of an overriding landslide. During the 2008 Wenchuan earthquake, about 60 000 landslides were triggered, directly resulting in about 20 000 casualties. While these landslides mainly originated from steep slopes, some landslides with high mobility formed in colluvial valley deposits. Among these, the most catastrophic was the Xiejiadian landslide in Pengzhou city, which traveled hundreds of meters before coming to rest. Through field investigation and laboratory testing, we conclude that this landslide primarily formed from colluvial deposits in the valley and secondarily from failure of slopes in granitic rock located uphill. Much of the granitic slope failure was deposited in the upper part of the travel path (near the slide head); the remainder was dispersed throughout the main landslide deposit. Superposition of deposits at the landslide toe indicates that landslide debris derived from colluvial soil was deposited first. The deposits at the landslide toe displayed flow characteristics, such as fine materials comprising basal layers and large boulders covering the deposit surface. We hypothesize that the main part of the landslide resulted from seismogenic liquefaction of valley colluvium, rather than from liquefaction potentially caused by undrained loading from the granitic slope failures impacting the colluvium. To examine the likelihood that seismogenic liquefaction occurred, we took samples from different areas of the landslide deposit and performed undrained cyclic shear tests on them in the laboratory. The results showed that the sandy soils that comprise most of the deposit are highly liquefiable under seismic loading. Therefore, we conclude that liquefaction of the colluvium in the valley during the earthquake was the main reason for this rapid (~46 m/s) long‐runout (1·7 km) landslide. Copyright © 2012 John Wiley & Sons, Ltd.
Using in situ pore water concentrations to estimate the phytotoxicity of nicosulfuron in soils to corn (Zea mays L.)
Authors: Liu Kailin , Cao Zhengya , Pan Xiong , Yu Yunlong 
Published: May 2012

Abstract
The phytotoxicity of an herbicide in soil is typically dependent on the soil characteristics. To obtain a comparable value of the concentration that inhibits growth by 50% (IC50), 0.01 M CaCl2, excess pore water (EPW) and in situ pore water (IPW) were used to extract the bioavailable fraction of nicosulfuron from five different soils to estimate the nicosulfuron phytotoxicity to corn (Zea mays L.). The results indicated that the phytotoxicity of nicosulfuron in soils to corn depended on the soil type, and the IC50 values calculated based on the amended concentration of nicosulfuron ranged from 0.77 to 9.77 mg/kg among the five tested soils. The range of variation in IC50 values for nicosulfuron was smaller when the concentrations of nicosulfuron extracted with 0.01 M CaCl2 and EPW were used instead of the amended concentration. No significant difference was observed among the IC50 values calculated from the IPW concentrations of nicosulfuron in the five tested soils, suggesting that the concentration of nicosulfuron in IPW could be used to estimate the phytotoxicity of residual nicosulfuron in soils. Environ. Toxicol. Chem. 2012; 31: 1705–1711. © 2012 SETAC
Development of a molecular biomarker for detecting intersex after exposure of male medaka fish to synthetic estrogen
Authors: Zhao Yanbin , Hu Jianying 
Published: May 2012

Abstract
Although intersex of fish species has been widely reported in aquatic environments, there is no appropriate biomarker of the effects to assess the occurrence of intersex. In the present study, mRNA expression profiles of 14 genes, which are either involved in ovary development and maintenance or have relatively high mRNA transcription levels in ovarian gene expression profiles in fish species, were comprehensively evaluated in male Japanese medaka (Oryzias latipes) exposed to 17α-ethynylestradiol (EE2) to investigate their utility as indicators of the severity index of intersex. Of these 14 genes, mRNA expression of a novel gene, termed ovary structure protein 1 (OSP1) in the present study, showed female-like expression pattern with the highest transcription levels, and displayed the most significantly positive correlation with the severity index of intersex (r2 = 0.8215, p &lt; 0.0001). The full-length mRNA sequence of OSP1 is 802 bp, with an open reading frame (ORF) of 642 bp that encodes a 214-amino acid peptide. Reverse transcription polymerase chain reaction and in situ hybridization revealed that OSP1 was expressed exclusively in the ovaries, specifically in the oogonia and primary oocytes in ovaries and in testis with intersex. These results suggest that the analysis of mRNA expression of OSP1 can be used to indicate intersex in male medaka. Environ. Toxicol. Chem. 2012; 31: 1765–1773. © 2012 SETAC
Protein‐based carbon capture: progress and potential
Authors: Drummond Michael L. , Cundari Thomas R. , Wilson Angela K. 
Published: May 2012

AbstractIncreasing atmospheric levels of CO2 and potential resulting climate changes require new, innovative solutions. As currently employed, carbon capture and sequestration (CCS) technology is unable, by orders of magnitude, to cope with the tremendous (and increasing) amount of anthropogenic CO2 emissions. In the biosphere, enzymatic CCS captures more than quadruple the amount of CO2 emitted by human activity, and so a bio‐inspired approach to CCS is greatly appealing. In this perspective, recent work concerning the ability of various CO2‐utilizing enzymes (Rubisco, carbonic anhydrase, and others) to act as carbon capture agents is discussed. Particular attention is given to computational modeling and simulation research, which has revealed useful, fundamental information about the way a protein interacts with carbon dioxide at the primary, secondary, and tertiary structure levels. Novel computational approaches that have been developed to rapidly screen proteins for their suitability for enzymatic CCS are discussed. It is proposed that increased carbon utilization must be incorporated into CCS, and furthermore that enzymatic utilization, especially when guided by computational modeling, will be a crucial component of success. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
T‐cell acute lymphoblastic leukaemia after liver transplantation: post‐transplant lymphoproliferative disorder or coincidental de novo leukaemia?
Authors: Fang Yanan , Pinkney Kerice A , Lee John C , Gindin Tatyana , Weiner Michael A , Alobeid Bachir , Bhagat Govind 
Published: May 2012

AbstractPost‐transplant lymphoproliferative disorders of T‐cell origin are quite uncommon, and the vast majority represent neoplasms of mature, post‐thymic T‐ or natural killer cells. Here, we report a rare case of T‐cell acute lymphoblastic leukaemia (T‐ALL), which occurred in an 18‐year‐old man who had undergone three liver transplants, initially for biliary atresia and subsequently for graft failure due to chronic rejection. He had received immunosuppression with cyclosporine and tacrolimus, as well as short‐term treatment with OKT3. The T‐ALL occurred 16 years after the first liver transplant. This case highlights the challenge for classifying rare neoplasms occurring in recipients of solid organ transplants that are currently not recognized to lie within the spectrum of post‐transplant lymphoproliferative disorders. Given the long interval between the liver transplants and the development of T‐ALL, a coincidental occurrence of the leukaemia cannot be ruled out. However, the potential roles of immunosuppressive therapy and other co‐morbid conditions of the individual as possible risk factors for the pathogenesis of T‐ALL are discussed. Copyright © 2012 John Wiley & Sons, Ltd.