bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Bott–Borel–Weil Theorem for Diagonal Ind-groups
Authors: Dimitrov Ivan , Penkov Ivan 
Published: May 2011

AbstractA diagonal ind-group is a direct limit of classical affine algebraic groups of growing rank under a class of inclusions that contains the inclusionas a typical special case. If G is a diagonal ind-group and B ⊂ G is a Borel ind-subgroup, we consider the ind-variety G/B and compute the cohomology H𝓁(G/B,𝒪−λ) of any G-equivariant line bundle 𝒪−λ on G/B. It has been known that, for a generic λ, all cohomology groups of 𝒪−λ vanish, and that a non-generic equivariant line bundle 𝒪−λ has at most one nonzero cohomology group. The new result of this paper is a precise description of when Hj (G/B,𝒪−λ) is nonzero and the proof of the fact that, whenever nonzero, Hj (G/B,𝒪−λ) is a G-module dual to a highest weight module. The main difficulty is in defining an appropriate analog WB of the Weyl group, so that the action of WB on weights of G is compatible with the analog of the Demazure “action” of the Weyl group on the cohomology of line bundles. The highest weight corresponding to Hj (G/B,𝒪−λ) is then computed by a procedure similar to that in the classical Bott–Borel–Weil theorem.
Diagnostic Value of Clinical Examination and Radiographic Imaging in Identification of Intraocular Foreign Bodies in Open Globe Injury
Authors: Patel Shriji N. , Langer Paul D. , Zarbin Marco A. , Bhagat Neelakshi 
Published: May 2011

Purpose To evaluate the diagnostic accuracy of clinical eye examination and radiographic imaging in the identification of intraocular foreign bodies (IOFBs) in open-globe traumatic injuries. Methods This was a retrospective chart review of open-globe traumatic injuries with IOFBs presenting to University Hospital (UH) at New Jersey Medical School between 1998 and 2008. Results A total of 527 patients with traumatic open globe injuries presented to UH, Newark, New Jersey, USA, between 1998 and 2008. Of these, 74 patients had surgically confirmed IOFBs. Mean age of patients with traumatic open globe injury and an IOFB was 33 years (range, 8-69 years); mean follow-up was 17.6 months (range, 1 day–90 months). Foreign bodies were identified as glass ( 13 ), metal (58), wood (1), plastic (0), and other (2). There were 24 anterior segment (AS) IOFBs, 45 posterior segment (PS) IOFBs, and 5 noted in both segments. Clinical eye examination at presentation identified an IOFB in 34 (45.6%) of 74 patients. B-scan echography revealed an IOFB in 14 (51.9%) of 27 cases. Computed tomography scan of the orbits identified IOFBs in 56 (94.9%) of 59 cases. Clinical eye examination was performed in all (100%) patients. B-scan was performed only when posterior segment pathology was suspected. Computed tomography scan was performed when an IOFB or orbital fracture was suspected. Conclusions Computed tomography scan was the most reliable method for identifying IOFBs in patients presenting with open globe injuries in comparison to clinical eye examination and B-scan echography. This result was consistent regardless of IOFB location within the globe.
Characterization of High‐Strain Rate Mechanical Behavior of AZ31 Magnesium Alloy Using 3D Digital Image Correlation
Authors: Wang Yanli , Xu Hanbing , Erdman Donald L. , Starbuck Michael J. , Simunovic Srdjan 
Published: May 2011

AbstractCharacterization of the material mechanical behavior at sub‐Hopkinson regime (0.1 to 1 000 s−1) is very challenging due to instrumentation limitations and the complexity of data analysis involved in dynamic loading. In this study, AZ31 magnesium alloy sheet specimens are tested using a custom designed servo‐hydraulic machine in tension at nominal strain rates up to 1 000 s−1. In order to resolve strain measurement artifacts, the specimen displacement is measured using 3D Digital Image correlation instead from actuator motion. The total strain is measured up to ≈ 30%, which is far beyond the measurable range of electric resistance strain gages. Stresses are calculated based on the elastic strains in the tab of a standard dog‐bone shaped specimen. Using this technique, the stresses measured for strain rates of 100 s−1 and lower show little or no noise comparing to load cell signals. When the strain rates are higher than 250 s−1, the noises and oscillations in the stress measurements are significantly decreased from ≈ 250 to 50 MPa. Overall, it is found that there are no significant differences in the elongation, although the material exhibits slight work hardening when the strain rate is increased from 1 to 100 s−1.
E‐Field Control of Exchange Bias and Deterministic Magnetization Switching in AFM/FM/FE Multiferroic Heterostructures
Authors: Liu Ming , Lou Jing , Li Shandong , Sun Nian X. 
Published: May 2011

AbstractThe coexistence of electrical polarization and magnetization in multiferroic materials provides great opportunities for novel information storage systems. In particular, magnetoelectric (ME) effect can be realized in multi­ferroic composites consisting of both ferromagnetic and ferroelectric phases through a strain mediated interaction, which offers the possibility of electric field (E‐field) manipulation of magnetic properties or vice versa, and enables novel multiferroic devices such as magnetoelectric random access memories (MERAMs). These MERAMs combine the advantages of FeRAMs (ferroelectric random access memories) and MRAMs (magnetic random access memories), which are non‐volatile magnetic bits switchable by electric field (E‐field). However, it has been challenging to realize 180° deterministic switching of magnetization by E‐field, on which most magnetic memories are based. Here we show E‐field modulating exchange bias and for the first time realization of near 180° dynamic magnetization switching at room temperature in novel AFM (antiferromagnetic)/FM (ferromagnetic)/FE (ferroelectric) multiferroic heterostructures of FeMn/Ni80Fe20/FeGaB/PZN‐PT (lead zinc niobate–lead titanate). Through competition between the E‐field induced uniaxial anisotropy and unidirectional anisotropy, large E‐field‐induced exchange bias field‐shift up to $ {{{\Delta H_{ex}}}\over{{H_{ex}}}} = 218\%$ and near 180° deterministic magnetization switching were demonstrated in the exchange‐coupled multiferroic system of FeMn/Ni80Fe20/FeGaB/PZN‐PT. This E‐field tunable exchange bias and near 180° deterministic magnetization switching at room temperature in AFM/FM/FE multiferroic heterostructures paves a new way for MERAMs and other memory technologies.
Iron Dihydride Complex as the Pre‐catalyst for Efficient Hydrosilylation of Aldehydes and Ketones Under Visible Light Activation
Authors: Castro Luis C. Misal , Bézier David , Sortais Jean‐Baptiste , Darcel Christophe 
Published: May 2011

AbstractA general and efficient hydrosilylation of aldehydes and ketones into the corresponding alcohols using the well‐defined bis(diphenylphosphinoethane)iron dihydride complex as the pre‐catalyst is reported using polymethylhydrosiloxane (PMHS) as the reducing silylating agent and sodium tetraethoxyborate [NaB(OEt)4] as a co‐catalyst under visible light irradiation. The low catalyst loadings (0.1–1 mol%), the amount of economical hydride source, PMHS and the unconventional way of activation of the pre‐catalyst make this new approach attractive.
Porous Silica Beads Supported TEMPO and Adsorbed NOx (PSB‐TEMPO/NOx): An Efficient Heterogeneous Catalytic System for the Oxidation of Alcohols under Mild Conditions
Authors: Di Lei , Hua Zhang 
Published: May 2011

AbstractThe combination of NOx gas which is stored in the pore canals of porous silica beads (PSB) with a heterogeneous catalyst, PSB‐supported 2,2,6,6‐tetramethylpiperdine 1‐oxyl (PSB‐TEMPO, 1), afforded a highly efficient, widely applicable, and efficiently recyclable approach for the selective aerobic oxidation of alcohols. This novel catalytic system (PSB‐TEMPO/NOx) can be employed in the oxidation of a wide range of alcohols to their corresponding aldehydes and ketones with selectivities as high as 99% at complete conversions under mild conditions. O2 is the terminal oxidant. PSB‐TEMPO can be recycled for more than 10 times without significant loss of activity.
New Polymer‐Supported Catalysts for the Asymmetric Transfer Hydrogenation of Acetophenone in Water – Kinetic and Mechanistic Investigations
Authors: Dimroth Jonas , Schedler Uwe , Keilitz Juliane , Haag Rainer , Schomäcker Reinhard 
Published: May 2011

AbstractHeterogenization is a powerful approach for the generation of easily recyclable catalysts. In this study, a modified tethered rhodium(III)‐ p‐toluenesulfonyl‐1,2‐diphenylethylenediamine (Rh‐TsDPEN) complex immobilized on polymeric supports was applied to kinetic and up‐scaling experiments on the asymmetric transfer hydrogenation of acetophenone in water. Study of the catalyst has helped in understanding some aspects of its operating mode. The results indicate that, in the investigated range, a simple second‐order model describes the enantioselective conversion of acetophenone to phenylethanol. Optimal reaction conditions were determined, and particularly the solution pH was found to play a decisive role for the activity and reusability of the catalyst. The good performance under optimized conditions emphasizes the practical usefulness of this recyclable catalytic system for environmentally benign asymmetric transfer hydrogenation processes.
The Pyridyldiisopropylsilyl Group: A Masked Functionality and Directing Group for Monoselective ortho‐Acyloxylation and ortho‐Halogenation Reactions of Arenes
Authors: Huang Chunhui , Chernyak Natalia , Dudnik Alexander S. , Gevorgyan Vladimir 
Published: May 2011

AbstractA novel, easily removable and modifiable silicon‐tethered pyridyldiisopropylsilyl directing group for CH functionalizations of arenes has been developed. The installation of the pyridyldiisopropylsilyl group can efficiently be achieved via two complementary routes using easily available 2‐(diisopropylsilyl)pyridine (5). The first strategy features a nucleophilic hydride substitution at the silicon atom in 5 with aryllithium reagents generated in situ from the corresponding aryl bromides or iodides. The second milder route exploits a highly efficient room‐temperature rhodium(I)‐catalyzed cross‐coupling reaction between 5 and aryl iodides. The latter approach can be applied to the preparation of a wide range of pyridyldiisopropylsilyl‐substituted arenes possessing a variety of functional groups, including those incompatible with organometallic reagents. The pyridyldiisopropylsilyl directing group allows for a highly efficient, regioselective palladium(II)‐catalyzed mono‐ortho‐acyloxylation and ortho‐halogenation of various aromatic compounds. Most importantly, the silicon‐tethered directing group in both acyloxylated and halogenated products can easily be removed or efficiently converted into an array of other valuable functionalities. These transformations include protio‐, deuterio‐, halo‐, boro‐, and alkynyldesilylations, as well as a conversion of the directing group into the hydroxy functionality. In addition, the construction of aryl‐aryl bonds via the Hiyama–Denmark cross‐coupling reaction is feasible for the acetoxylated products. Moreover, the ortho‐halogenated pyridyldiisopropylsilylarenes, bearing both nucleophilic pyridyldiisopropylsilyl and electrophilic aryl halide moieties, represent synthetically attractive 1,2‐ambiphiles. A unique reactivity of these ambiphiles has been demonstrated in efficient syntheses of arylenediyne and benzosilole derivatives, as well as in a facile generation of benzyne. In addition, preliminary mechanistic studies of the acyloxylation and halogenation reactions have been performed. A trinuclear palladacycle intermediate has been isolated from a stoichiometric reaction between diisopropyl(phenyl)pyrid‐2‐ylsilane (3a) and palladium acetate. Furthermore, both CH functionalization reactions exhibited equally high values of the intramolecular primary kinetic isotope effect (kH/kD=6.7). Based on these observations, a general mechanism involving the formation of a palladacycle via a CH activation process as the rate‐determining step has been proposed.
Tandem Catalysis by Lipase in a Vinyl Acetate‐Mediated Cross‐Aldol Reaction
Authors: Kumar Manjeet , Shah Bhahwal A. , Taneja Subhash C. 
Published: May 2011

AbstractThe lipase Novozym435 (0.6% w/w) was used in tandem with organocatalysts in a first vinyl/isopropenyl acetate‐mediated aldol reaction. The reaction was facilitated through the lipase‐catalyzed in situ generation of acetaldehyde/acetone. The important features of the present methodology include the mild and facile reaction conditions, regenerability of the lipase, comparatively high yields and minimal side product formation.
Convenient and Selective Hydrogenation of Nitro Aromatics with a Platinum Nanocatalyst under Ambient Pressure
Authors: Xu Kunling , Zhang Yuan , Chen Xiaorong , Huang Lei , Zhang Rui , Huang Jun 
Published: May 2011

AbstractA convenient and highly selective platinum nanocatalyst was developed for the hydrogenation of nitro aromatics into the corresponding anilines at room temperature under ambient pressure. The platinum catalyst was highly active and selective for the hydrogenation of nitro aromatic compounds. Reducible groups such as aldehyde, ketone and nitrile were untouched during the hydrogenation of the corresponding nitro compounds, and the corresponding anilines were obtained quantitatively.
Magnetically Recoverable Nanoparticles: Highly Efficient Catalysts for Asymmetric Transfer Hydrogenation of Aromatic Ketones in Aqueous Medium
Authors: Liu Guohua , Gu Hongyuan , Sun Yunqiang , Long Jie , Xu Yulong , Li Hexing 
Published: May 2011

AbstractTwo magnetic chiral iridium and rhodium catalysts were prepared via directly postgrafting 1,2‐diphenylethylenediamine‐derived organic silica or 1,2‐cyclohexanediamine‐derived organic silica onto the silica‐coated iron oxide nanoparticles followed by complexation with iridium(III) or rhodium(III) complexes. During the asymmetric transfer hydrogenation of aromatic ketones in aqueous medium, the magnetic chiral catalysts exhibited high catalytic activities (up to 99% conversion) and enantioselectivities (up to 92% ee). Both catalysts could be recovered easily by magnetic separation and be reused ten times without significantly affecting their catalytic activities and enantioselectivities.
Mechanistic Switch via Subtle Ligand Modulation: Palladium‐Catalyzed Synthesis of α,β‐Substituted Styrenes via CH Bond Functionalization
Authors: Flores‐Gaspar Areli , Martin Ruben 
Published: May 2011

AbstractA new catalyst system able to efficiently perform the synthesis of styrenes via CH bond functionalization and a subtle ligand modification are described. The high level of activity achieved allows for the synthesis of highly functionalized α,β‐substituted styrenes, even the elusive E‐configured trisubstituted olefins, in a regio‐ and stereoselective manner. Mechanistic experiments allowed for the identification of the corresponding synthetic intermediates.
Grignard‐Type Arylation of Aldehydes via a Rhodium‐Catalyzed CH Activation under Mild Conditions
Authors: Yang Luo , Correia Camille A. , Li Chao‐Jun 
Published: May 2011

AbstractAn efficient Grignard‐type arylation of aldehydes via aryl CH activation was achieved under mild conditions catalyzed by rhodium. The reaction provides an easy access to a wide variety of benzyl alcohols and can tolerate various functional groups as well as air and water.
IRon overload screeNing tool (IRON): Development of a tool to guide screening in primary care
Authors: Mainous Arch G. , Diaz Vanessa A. , Everett Charles J. , Knoll Michele E. , Hulihan Mary M. , Grant Althea M. , McLaren Christine E. , McLaren Gordon D. 
Published: May 2011

AbstractIron overload is associated with significant morbidity and mortality yet is easily treated. The objective of this study was to create a tool that could be easily adapted to clinical practice that indicates the likelihood of a patient having undetected iron overload. We used the National Health and Nutrition Examination Survey (NHANES) 1999–2002 for US adults aged 20 years and older to build a model (unweighted n=8,779). We chose potential variables for inclusion that could be gathered by self‐report or measured without laboratory data and were suggested by past literature on hemochromatosis and iron overload. We computed logistic regressions to create the scores by initially evaluating the variables' relationship with elevated ferritin and elevated transferrin saturation and then using odds ratios to correspond to scores. The resulting score on the IRon Overload ScreeNing Tool (IRON) was then validated with data on 13,844 adults in the NHANES III, 1988–94. Predictors in the final tool were age, gender, previous diagnoses of liver condition, osteoporosis or thyroid disease. The IRON score yielded an area under the curve (AUC) in the NHANES 1999–02 of 0.720 and an AUC of 0.685 in the NHANES III validation sample. The IRON score is a tool to assist in identification of patients with iron overload that has several qualities that make it attractive for use in clinical practice with an undifferentiated patient population including brevity, easily collected information and predictive ability comparable to other tools that help in directing screening. Am. J. Hematol. 2011. © 2011 Wiley‐Liss, Inc.
Carious lesions and maize consumption among the Prehispanic Maya: An analysis of a coastal community in northern Yucatan
Authors: Cucina Andrea , Cantillo Cristina Perera , Sosa Thelma Sierra , Tiesler Vera 
Published: May 2011

AbstractPatterns of carious lesions were analyzed in the Classic period coastal Maya population of Xcambó, a salt production and administration center in northern Yucatan. To this end, the study investigated caries in the permanent dentitions of 163 adult skeletons, 23 from the Early Classic (AD 250–550) and 140 from the Late Classic period (AD 550–750), equally distributed between sexes. The archaeological and bioarchaeological evidence indicates a wealthy and socially homogeneous population dedicated to salt production and administration in the Early Classic that switched to pure administrative functions in the Late Classic. The results indicate an increase in caries from 7.4% and 21.2% (males and females respectively) from the Early Classic to 14.0% in males and 27.4% in females from the Late Classic period. The rate of caries in the Early and in the Late Classic phases of continuous occupation is not consistent with a simple interpretation of a heavier reliance on maize during the latter phase, characterized by a sedentary lifestyle, particularly for the male segment of the society now dedicated completely to the administration of the salt mines. Rather, the increase in caries rates in both sexes is best explained within a broader context of overall food habits, new cariogenic foods for both sexes, and the changes in lifestyle imposed by the increased socioeconomic role of the site. Our conclusions stress the limitations imposed by interpreting carious lesions solely in terms of single dietary components, such as maize consumption, without taking into account broader aspects of cultural and socioeconomic relevance. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Tooth evolution and dental defects: From genetic regulation network to micro‐RNA fine‐tuning
Authors: Michon Frederic 
Published: May 2011

AbstractTeeth, like all epithelial appendages, form via a sequential and reciprocal series of inductive signals between the epithelium and the underlying mesenchyme. The genes involved in this signaling network regulating ectodermal organ development have been highly conserved during evolution and are gaining more understanding in great detail. The specific functions of numerous genes during embryogenesis are known, and the involvement of their mutations in the pathogenesis of congenital defects is being extensively studied. Recently, the micro‐RNA (miRNA) pathway has been associated with various aspects of embryogenesis including ectodermal organ formation and odontogenesis. In this review, I presented the genetic network involved during tooth formation and evolution, and several mutations that give rise to dental defects. The possible impact of fine‐tuning and network regulation by miRNAs on development, evolution of teeth, and defects are, therefore, discussed. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.
Tbx1, subpulmonary myocardium and conotruncal congenital heart defects
Authors: Parisot Pauline , Mesbah Karim , Théveniau–Ruissy Magali , Kelly Robert G. 
Published: May 2011

AbstractConotruncal congenital heart defects, including defects in septation and alignment of the ventricular outlets, account for approximately a third of all congenital heart defects. Failure of the left ventricle to obtain an independent outlet results in incomplete separation of systemic and pulmonary circulation at birth. The embryonic outflow tract, a transient cylinder of myocardium connecting the embryonic ventricles to the aortic sac, plays a critical role in this process during normal development. The outflow tract (OFT) is derived from a population of cardiac progenitor cells called the second heart field that contributes to the arterial pole of the heart tube during cardiac looping. During septation, the OFT is remodeled to form the base of the ascending aorta and pulmonary trunk. Tbx1, the major candidate gene for DiGeorge syndrome, is a critical transcriptional regulator of second heart field development. DiGeorge syndrome patients are haploinsufficient for Tbx1 and present a spectrum of conotruncal anomalies including tetralogy of Fallot, pulmonary atresia, and common arterial trunk. In this review, we focus on the role of Tbx1 in the regulation of second heart field deployment and, in particular, in the development of a specific population of myocardial cells at the base of the pulmonary trunk. Recent data characterizing additional properties and regulators of development of this region of the heart, including the retinoic acid, hedgehog, and semaphorin signaling pathways, are discussed. These findings identify future subpulmonary myocardium as the clinically relevant component of the second heart field and provide new mechanistic insight into a spectrum of common conotruncal congenital heart defects. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.
Structural evidence for stabilization of inhibitor binding by a protein cavity in the dehaloperoxidase‐hemoglobin from Amphitrite ornata
Authors: de Serrano Vesna , Franzen Stefan 
Published: May 2011

AbstractA functional role for a protein cavity that stabilizes inhibitor binding has been established based on a comparison of Xe‐derivatized and inhibitor‐bound X‐ray crystal structures in dehaloperoxidase‐hemoglobin (DHP A) of Amphitrite ornata. The internal binding affinity of four different inhibitors, 4‐fluorophenol, 4‐chlorophenol, 4‐bromophenol, and 4‐iodophenol in the distal pocket has been shown previously to increase proportional to the radius of the para‐halogen atom. Inhibition of oxidation of the native substrate, 2,4,6‐tribromophenol, has been shown to follow the trend in inhibitor binding strength, because of a two‐site competitive inhibition mechanism that involves displacement of the substrate by the inhibitor in a gated mechanism involving the distal histidine of DHP A. In this study, it is shown that the origin of the stronger binding by a larger para‐halogen substituent coincides structurally with a Xe‐binding cavity (Xe1) characterized structurally by X‐ray crystallography. The Xe1 site is surrounded by amino acid resides L100, F21, F24, F35, F60, and V59 in the distal pocket, located 4.8 Å from the heme iron, in a position that is coincident with the para‐bromine atom of the inhibitor 4‐bromophenol. 4‐bromophenol is prevalent in benthic ecosystems where A. ornata resides. A second, less well‐defined, binding site in DHP A, labeled as Xe2, is located near the surface of the protein in the vicinity of amino acid residues L62, R69, D79, T82, and L83, which may be related to substrate docking on the surface of DHP A. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 27–35, 2012.