bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis error covarianceversusposterior covariance in variational data assimilation
Authors: Gejadze I. Yu. , Shutyaevb V. , Dimetc F.‐X. Le 
Published: December 2012

AbstractThe problem of variational data assimilation for a nonlinear evolution model is formulated as an optimal control problem to find the initial condition function (analysis). The data contain errors (observation and background errors); hence there is an error in the analysis. For mildly nonlinear dynamics the analysis error covariance can be approximated by the inverse Hessian of the cost functional in the auxiliary data assimilation problem, and for stronger nonlinearity by the ‘effective’ inverse Hessian. However, it has been noticed that the analysis error covariance is not the posterior covariance from the Bayesian perspective. While these two are equivalent in the linear case, the difference may become significant in practical terms with the nonlinearity level rising. For the proper Bayesian posterior covariance a new approximation via the Hessian is derived and its ‘effective’ counterpart is introduced. An approach for computing the mentioned estimates in the matrix‐free environment using the Lanczos method with preconditioning is suggested. Numerical examples which validate the developed theory are presented for the model governed by Burgers equation with a nonlinear viscous term.
Exploration of the reactivity of N2O5 with two Si(OH)4 monomers using electronic structure methods
Authors: Messaoudi Sabri , Bejaoui Bechir , Akrout Fourat , Bel Hassen Malika , Sammari Cherif 
Published: December 2012

AbstractThe heterogeneous uptake of N2O5 on mineral dust particles may play an important role in the removal of nitrogen oxides from the atmosphere. However, the reaction of N2O5 with the mineral particles is not well understood. The reaction of N2O5 with two Si(OH)4 monomers is explored using theoretical methods. This study represents a first step towards understanding the interaction of N2O5 with the hydroxyl groups of silica particles. Energies are calculated using MP2 single point calculations on the B3LYP optimized geometries and including B3LYP thermodynamic corrections. Four mechanisms are considered for the formation of two HNO3 and one H6Si2O7. The rate limiting activation barrier of the most favorable path is found to be 12.5 kcal mol−1. This reaction appears to be more favorable than the hydrolysis of N2O5 with one water molecule. These results are in agreement with experimental observations, which show that N2O5 reacts with OH groups of Saharan dust to form nitrate. © 2012 Wiley Periodicals, Inc.
Contribution of dendritic cells to measles virus induced immunosuppression
Authors: Coughlin Melissa M. , Bellini William J. , Rota Paul A. 
Published: December 2012

SUMMARYMeasles virus (MV) remains an important pathogen in children worldwide. The morbidity and mortality of MV is associated with severe immune suppression. Dendritic cells (DCs) were identified as initial target cells in vivo, and DCs were efficiently infected by MV in vitro. MV infection of DCs likely contributes to functional deficiency in these cells; therefore playing a role in MV‐induced immunosuppression. DCs appeared to mature phenotypically; however, the ability of infected cells to stimulate T cells was compromised. Phenotypic maturation of infected immature DCs was partially controlled by IFN production; however, infected DCs also maintained markers of an immature phenotype such as the continued uptake of antigen and lack of expression of chemokine receptor CCR7. Furthermore, mature DCs did not appear to maintain phenotypic maturation following infection demonstrated by decreased MHC and co‐stimulatory molecule expression. Several mechanisms of MV‐induced DC dysfunction have been suggested, each likely contributing to the immunosuppressive effect of MV‐infected DCs. Infected DCs responded aberrantly to secondary maturation stimuli such as CD40L or TLR4 stimulation. MV infection resulted in apoptosis in DC/T‐cell cocultures, which may contribute to a reduced T‐cell response. Additionally, the immunological synapse between infected DCs and T cells was compromised resulting in reduced T‐cell interaction times and activation signaling. The mechanisms of MV contribution to DC dysfunction appear multifaceted and central to MV‐induced immunosuppression. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Plasmonic Amplifiers: Engineering Giant Light Enhancements by Tuning Resonances in Multiscale Plasmonic Nanostructures
Authors: Chen Aiqing , Miller Ryan L. , DePrince A. Eugene , Joshi‐Imre Alexandra , Shevchenko Elena , Ocola Leonidas E. , Gray Stephen K. , Welp Ulrich , Vlasko‐Vlasov Vitalii K. 
Published: December 2012

AbstractThe unique ability of plasmonic nanostructures to guide, enhance, and manipulate subwavelength light offers multiple novel applications in chemical and biological sensing, imaging, and photonic microcircuitry. Here the reproducible, giant light amplification in multiscale plasmonic structures is demonstrated. These structures combine strongly coupled components of different dimensions and topologies that resonate at the same optical frequency. A light amplifier is constructed using a silver mirror carrying light‐enhancing surface plasmons, dielectric gratings forming distributed Bragg cavities on top of the mirror, and gold nanoparticle arrays self‐assembled into the grating grooves. By tuning the resonances of the individual components to the same frequency, multiple enhancement of the light intensity in the nanometer gaps between the particles is achieved. Using a monolayer of benzenethiol molecules on this structure, an average SERS enhancement factor <EF> ∼108 is obtained, and the maximum enhancement in the interparticle hot‐spots is ∼3 × 1010, in good agreement with FDTD calculations. The high enhancement factor, large density of well‐ordered hot‐spots, and good fidelity of the SERS signal make this design a promising platform for quantitative SERS sensing, optical detection, efficient solid state lighting, advanced photovoltaics, and other emerging photonic applications.
An alternative procedure for seismic evaluation and strengthening of tall buildings
Authors: Hart Gary C. , Brandow Gregg E. , Brugger Larry , Carpenter Lauren D. , Quadri Nick Delli , Huang Sampson C. , Kashefi Ifa , Kumabe Colin , Lew Marshall 
Published: December 2012

SUMMARYThe goal of existing building codes and standards for the evaluation and strengthening of existing buildings is to provide for safe buildings by prescribing loads and material properties and structural analysis methods for a broad spectrum of building heights, types and construction. Experience clearly shows that building codes and standards do not provide for the most economical, efficient and safe tall buildings because the codes are general and prescriptive in nature and do not allow the structural engineer the flexibility without significant difficulty to incorporate building‐specific applicable experience, education and new technologies. Tall buildings are really a special class of buildings that have unique qualities and characteristics. The design of tall buildings has been recognized by the structural engineering profession to require more care and effort in both design and construction because of the need to meet safety and performance requirements. This recognition is based in part on the large number of people at risk in tall buildings and also the negative financial impact on the community and the building owner. To meet this need, an alternative procedure for Seismic Evaluation and Strengthening of Existing Tall Buildings in the Los Angeles region is under development by the Los Angeles Tall Buildings Structural Design Council. This paper presents a progress report on this development. Copyright © 2012 John Wiley & Sons, Ltd.
Assembly of Bacteriophage into Functional Materials
Authors: Yang Sung Ho , Chung Woo‐Jae , McFarland Sean , Lee Seung‐Wuk 
Published: December 2012

ABSTRACT:For the last decade, the fabrication of ordered structures of phage has been of great interest as a means of utilizing the outstanding biochemical properties of phage in developing useful materials. Combined with other organic/inorganic substances, it has been demonstrated that phage is a superior building block for fabricating various functional devices, such as the electrode in lithium‐ion batteries, photovoltaic cells, sensors, and cell‐culture supports. Although previous research has expanded the utility of phage when combined with genetic engineering, most improvements in device functionality have relied upon increases in efficiency owing to the compact, more densely packable unit size of phage rather than on the unique properties of the ordered nanostructures themselves. Recently, self‐templating methods, which control both thermodynamic and kinetic factors during the deposition process, have opened up new routes to exploiting the ordered structural properties of hierarchically organized phage architectures. In addition, ordered phage films have exhibited unexpected functional properties, such as structural color and optical filtering. Structural colors or optical filtering from phage films can be used for optical phage‐based sensors, which combine the structural properties of phage with target‐specific binding motifs on the phage‐coat proteins. This self‐templating method may contribute not only to practical applications, but also provide insight into the fundamental study of biomacromolecule assembly in in vivo systems under complicated and dynamic conditions.
Design, Synthesis, and Evaluation of Bioactive Small Molecules
Authors: Hua Duy H. 
Published: December 2012

ABSTRACT:Collaborative research projects between chemists, biologists, and medical scientists have inevitably produced many useful drugs, biosensors, and medical instrumentation. Organic chemistry lies at the heart of drug discovery and development. The current range of organic synthetic methodologies allows for the construction of unlimited libraries of small organic molecules for drug screening. In translational research projects, we have focused on the discovery of lead compounds for three major diseases: Alzheimer's disease (AD), breast cancer, and viral infections. In the AD project, we have taken a rational‐design approach and synthesized a new class of tricyclic pyrone (TP) compounds that preserve memory and motor functions in amyloid precursor protein (APP)/presenilin‐1 (PS1) mice. TPs could protect neuronal death through several possible mechanisms, including their ability to inhibit the formation of both intraneuronal and extracellular amyloid β (Aβ) aggregates, to increase cholesterol efflux, to restore axonal trafficking, and to enhance long‐term potentiation (LTP) and restored LTP following treatment with Aβ oligomers. We have also synthesized a new class of gap‐junction enhancers, based on substituted quinolines, that possess potent inhibitory activities against breast‐cancer cells in vitro and in vivo. Although various antiviral drugs are available, the emergence of viral resistance to existing antiviral drugs and various understudied viral infections, such as norovirus and rotavirus, emphasizes the demand for the development of new antiviral agents against such infections and others. Our laboratories have undertaken these projects for the discovery of new antiviral inhibitors. The discussion of these aforementioned projects may shed light on the future development of drug candidates in the fields of AD, cancer, and viral infections.
Value of annular M‐mode displacement vs tissue Doppler velocities to assess cardiac function in intrauterine growth restriction
Authors: Cruz‐Lemini M. , Crispi F. , Valenzuela‐Alcaraz B. , Figueras F. , Sitges M. , Gómez O. , Bijnens B. , Gratacós E. 
Published: December 2012

ABSTRACTObjectiveTo compare the ability of two different methods for longitudinal annular motion measurement, M‐mode and tissue Doppler imaging (TDI), to demonstrate cardiac dysfunction in intrauterine‐growth‐restricted (IUGR) fetuses.MethodsCardiac longitudinal annular motion in the basal free wall of the left ventricle (mitral annulus), interventricular septum and tricuspid annulus was assessed in 23 early‐onset IUGR cases and 43 controls by TDI (annular peak velocities) and M‐mode (displacement).ResultsAll annular parameters were significantly decreased in the IUGR group with respect to controls using both methods. M‐mode showed a trend towards equal performance as classifier between cases and controls, as compared to TDI, mainly in the tricuspid annulus.ConclusionsBoth M‐mode and TDI demonstrate annular motion changes and consequently cardiac dysfunction in IUGR fetuses. M‐mode imaging is simpler to perform and could be as sensitive as TDI for detecting subtle changes. Copyright © 2012 ISUOG. Published by John Wiley & Sons Ltd.
The role of local knowledge in adaptation to climate change
Authors: Naess Lars Otto 
Published: December 2012

AbstractEvidence from recent research suggests that local knowledge may contribute to adaptation to climate change in a number of ways. At the same time, there are concerns over its relevance for future adaptation amidst other challenges. This article aims to shed light on some of the key potentials and challenges for the application of local knowledge for adaptation, drawing on recent studies as well as findings from semi‐arid Tanzania. This article illustrates how the role of local knowledge at the local level is determined by interaction between informal and formal institutions at the local level. It suggests that assessments of the role of local knowledge for adaptation need to give more consideration to local power relations and the interaction with government strategies, while also addressing structural constraints to the use of local knowledge across scales. WIREs Clim Change 2013, 4:99–106. doi: 10.1002/wcc.204This article is categorized under:

Vulnerability and Adaptation to Climate Change > Institutions for Adaptation
Cannabinoid activation of peroxisome proliferator‐activated receptors: an update and review of the physiological relevance
Authors: O'Sullivan Saoirse Elizabeth 
Published: December 2012

AbstractSince 2002, evidence has been building that cannabinoids, including endocannabinoids and endocannabinoid‐like compounds, phytocannabinoids and synthetic cannabinoid ligands, bind to and activate the different isoforms of the nuclear receptors, peroxisome proliferator‐activated receptors (PPARs; α, β, and γ). This has been shown through the use of reporter gene assays, binding studies, the use of antagonists and knockout animals. Increasing use of tools to assess a potential role for PPAR activation in underpinning the physiological effects of cannabinoids means that a picture is emerging of the relevance of PPAR activation by cannabinoids. There is now evidence that activation of PPARα and γ mediate some of the anti‐inflammatory, analgesic, neuroprotective, and cardiovascular effects of cannabinoids, sometimes in combination with activation of the more traditional target sites of action such as CB1, CB2, and TRPV1. There is also a role for PPARα activation by cannabinoids in some of their central effects including memory acquisition, reward processing, food intake and body weight regulation. Activation of PPARγ plays a role in the apoptotic effects of cannabinoids. However, much further work is required to fully establish the profile of cannabinoid compounds at all isoforms of the PPAR family and the relevance of this in normal physiology and pathological situations. WIREs Membr Transp Signal 2013, 2:17–25. doi: 10.1002/wmts.73For further resources related to this article, please visit the WIREs website.Conflict of interest: The author declare no conflict of interest.
Syntheses, Structures, and Catalytic Activity of Copper(II)‐Aroylhydrazone Complexes
Authors: Hosseini‐Monfared Hassan , Pousaneh Elaheh , Sadighian Somayeh , Ng Seik Weng , Tiekink Edward R. T. 
Published: December 2012

AbstractTwo CuII complexes of tridentate Schiff base ligands, [Cu(L1)(CH3OH)2]NO3·CH3OH (1) and [Cu2(L2)2(CH3OH)2](NO3)2 (2), were prepared and characterized by elemental analyses and spectroscopic methods [H2L1 = (E)‐N‐(4‐hydroxy benzoic acid (2‐hydroxy‐3‐methoxybenzylidene)benzohydrazide, and H2L2 = (E)‐N‐4‐hydroxy benzoic acid (5‐bromo‐2‐hydroxybenzylidene)benzohydrazide]. The crystal structures of 1 and 2 were established by X‐ray crystallography. The complex cation in 1 is based on a square pyramid with the uninegative Schiff base coordinating in a tridentate mode via O, N, O′‐donor atoms with the remaining sites being occupied by two methanol oxygen atoms with one of these in the axial position. By contrast, the Schiff base coordinates in a tridentate ligand fashion in dinuclear compound 2 as the phenoxide oxygen atom bridges two central copper atoms. The NO4 coordination donor set is completed by a methanol oxygen atom, which occupies an axial position in the distorted square pyramidal arrangement. Complexes 1 and 2 are very active catalysts in clean epoxidation reactions using aqueous hydrogen peroxide and acetonitrile. The effects of reaction parameters such as solvent and oxidant in the epoxidation of cis‐cyclooctene were investigated and showed that cyclooctene and cyclohexene were oxidized efficiently to their corresponding epoxide with 100 and 31 % selectivity, respectively, in the presence of catalyst 2. This catalytic system showed also excellent selectivity in the oxidation of benzyl alcohol.
Stabilization of Decatellurium Molecules in Isolated and Concatenated Clusters
Authors: Günther Anja , Isaeva Anna , Ruck Michael 
Published: December 2012

AbstractBlack, shiny crystals of the molecular cluster compounds (Te10)[M(TeX4)(TeX3)]2 (M/X = Rh/Cl (1), Ir/Br (2)), (Te10)[Ru(TeI4)(TeI2)]2 (3), (Te10)[M(TeI4)(TeI2)]2(TeI4)(Te2I2) (M = Rh (4), Ir (5)) as well as the one‐dimensional cluster polymer (Te10I2)[Ir(TeI4)]2(Te4)I2 (6) were synthesized by melting reactions of an electron‐rich transition metal M (M = Ru, Rh, Ir) with tellurium and TeX4 (X = Cl, Br, I). X‐ray diffraction on single‐crystals revealed that the compounds crystallize in the triclinic space group type P$\bar{1}$. 4 and 5 show [3+1]‐dimensional modulations of their structures. All compounds contain binuclear complexes with central μ‐η4:η4‐bridging Te10 units and terminal halogenidotellurate(II) groups. Each of the transition metal cations is in a slightly distorted octahedral coordination by six tellurium atoms; the two [MTe6] octahedra share a common edge. With the tellurium atoms acting as electron‐pair donors, the 18 electron rule is fulfilled for the electrophilic M atoms. The central tricyclo[5.1.1.13, 5]‐decatellurium molecule consists of two ecliptically stacked Te4 rings, which are linked through two tellurium atoms. The symmetric or asymmetric 3c4e bonds along these almost linear bridges are in analogy to polyanionic forms of tellurium, while the tricyclic conformation is stabilized by the strong bonding to the transition‐metal cations. Multi‐center bonding (3c4e) is also present in the terminal square [Te+IIX4]2– and the T‐shaped [Te+IIX3]– groups. The crystal structures of 4 and 5 are organized in layers of (Te10)[M(TeI4)(TeI2)]2n+ clusters (n ≤ 2) that are quite robust upon oxidation or reduction as shown by molecular calculations. These clusters alternate with incommensurately modulated layers that probably consist of TeI42– anions and a previously unknown Te2I2 molecule. The uncertainty arises primarily from equal scattering powers of I and Te atoms as well as from the known flexibility of the electron count of the Te10 unit. In 6, neutral Te4 rings concatenate (Te10I2)[Ir(TeI4)]2 clusters into chains, which run parallel to the a axis.
Gold(III) Carboxylate Complexes with N, N‐Chelating Ligands: Synthesis, Structure, and Features of IR Spectra
Authors: Akhmadullina Nailya S. , Borissova Aleksandra O. , Garbuzova Irina A. , Retivov Vasiliy M. , Sandu Roman A. , Kargin Yuri F. , Shishilov Oleg N. 
Published: December 2012

AbstractNew gold(III) carboxylate complexes [(L)Au(RCO2)2]BF4 (R = CH3, CMe3, CF3) with N, N‐chelating ligands L (L = phenanthroline, 2, 2′‐bipyridine), were obtained by the treatment of corresponding chloride complexes [(L)AuCl2]BF4 with silver(I) carboxylates. The structure of [(bipy)Au(CF3CO2)2]BF4 complex was determined by X‐ray diffraction analysis. When five‐coordinate gold(III) complexes [(L)AuCl3] (L = 2, 9‐dimethyl‐1, 10‐phenanthroline, 2, 2′‐biquinoline) were used as starting materials the same reaction led to unstable products, which could not to be isolated and characterized. The reactivity of chloride complexes towards different carboxylates as well as properties of resulting carboxylate compounds depends on the nature of substitute R in carboxylate groups as it was predicted by us earlier using quantum‐chemical calculations. In order to explain a difference in behaviors of four‐ and five‐coordinate gold(III) complexes infrared and far‐infrared spectra of chlorides and carboxylates were studied.
Synthesis and Crystal Structures of Antimony(III) Complexes With a Bis(amino)silane Ligand
Authors: Ma Xiaoli , Ding Yi , Roesky Herbert W. , Sun Shuai , Yang Zhi 
Published: December 2012

AbstractBis(amino)silane bearing bulky substituents on nitrogen, LH2 [L = Me2Si(NDipp)2, Dipp = 2, 6‐diisopropylphenyl] was reacted with nBuLi (ratio 1:1 and 1:2) in toluene. The Me2Si(LiNDipp)2 was treated with SbCl3 in a 1:1 ratio to yield the four‐membered SiN2Sb ring compound of composition [η2(N,N)‐Me2Si(NDipp)2SbCl] (1). The mono lithiated bis(amino)silane was used to synthesize the monodentate heterotetraatomic complex [(η1‐Me2SiNDipp)NHDippSbCl2] (2) by the reaction with SbCl3. The complexes were characterized by 1H and 13C NMR, elemental analysis, IR, and single‐crystal X‐ray structural analysis.
Synthesis, Structure, and Characterization of a New Metal‐Organic Framework containing Meso‐Helices
Authors: Fan Linlin , Chen Haiyan , Xiao Dongrong , Wang Enbo 
Published: December 2012

AbstractThe new metal‐organic framework [Cd(bqdc)(phen)]n (1) (bqdc = 2, 2′‐biquinoline‐4, 4′‐dicarboxylate, phen = 1, 10‐phenanthroline) was hydrothermally synthesized by hetero‐ring carboxylate ligand and N‐containing auxiliary ligand. The structure of 1 was determined by single‐crystal X‐ray diffraction analysis and further characterized by elemental analyses, IR spectroscopy, X‐ray powder diffraction, and TG analysis. Single‐crystal X‐ray structural analysis shows that complex 1 is an infinite two‐dimensional framework containing aesthetic meso‐helix. These two‐dimensional coordination networks are interconnected through aromatic π–π stacking and C–H···O hydrogen bonding interactions to afford a 6‐connected (412.63) three‐dimensional supramolecular architecture. Furthermore, the photoluminescent property of complex 1 was studied.
Metastable Phase Formation of Indium Monochloride from an Amorphous Feedstock
Authors: Bach Andreas , Fischer Dieter , Jansen Martin 
Published: December 2012

AbstractWe have studied the structural evolution of crystalline InCl starting from an amorphous deposit, generated by PVD on a sapphire substrate kept at –196 and –228 °C. The first crystalline modification occurred at heating up to –100 °C and was identified as β‐InCl, the high temperature modification. Formation of metastable β‐InCl at the conditions given can only be rationalized by assuming control of phase formation by more efficient nucleation of the metastable, low density polymorph in accordance with the Ostwald‐Vollmer rule. At 70 °C the system becomes sufficiently activated that the equilibrium polymorph α‐InCl occurs, which in a reversible process finally transforms to β‐InCl. During subsequent cooling to room temperature the α‐InCl is recovered.